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Low temperature is one of the main abiotic stresses that affects plant growth, causing serious damage or even death to plants. The differential expression of the TaEXPA19 gene in the above and underground parts of winter wheat and the implications for cold resistance remain unclear. In this study, the TaEXPA19 gene was cloned and analysed for expression in winter wheat, and transgenic Arabidopsis thaliana was constructed to investigate the effect of the TaEXPA19 gene in response to low‐temperature stress on plant growth. The TaEXPA19‐A and TaEXPA19‐D genes have different response patterns in the above and underground parts of transgenic A. thaliana. When plants were subjected to low‐temperature stress, the leaves were quickly upregulated and the roots were downregulated, and then upregulated to respond to low‐temperature stress to promote the growth of leaf length and leaf width petiole length. The results indicated that TaEXPA19 genes could improve low‐temperature tolerance in plants. The results of this study laid a foundation for the study of the cold resistance of winter wheat. [ABSTRACT FROM AUTHOR]

A number of studies have demonstrated that epigenetic factors regulate plant developmental timing in response to environmental changes. However, we still have an incomplete view of how epigenetic factors can regulate developmental events such as organogenesis, and the transition from cell division to cell expansion, in plants. The small number of cell types and the relatively simple developmental progression required to form the Arabidopsis petal makes it a good model to investigate the molecular mechanisms driving plant organogenesis. In this study, we investigated how the RABBIT EARS (RBE) transcriptional repressor maintains the downregulation of its downstream direct target, TCP5, long after RBE expression dissipates. We showed that RBE recruits the Groucho/Tup1-like corepressor TOPLESS (TPL) to repress TCP5 transcription in petal primordia. This process involves multiple layers of changes such as remodeling of chromatin accessibility, alteration of RNA polymerase activity, and histone modifications, resulting in an epigenetic memory that is maintained through multiple cell divisions. This memory functions to maintain cell divisions during the early phase of petal development, and its attenuation in a cell division-dependent fashion later in development enables the transition from cell division to cell expansion. Overall, this study unveils a novel mechanism by which the memory of an epigenetic state, and its cell-cycle regulated decay, acts as a timer to precisely control organogenesis. Author summary: Epigenetic changes, such as histone modifications or DNA methylation, can modify gene expression without affecting the genetic code. Such alterations can persist for many cell generations, and often are induced by various environmental inputs in both plants and animals. By contrast, little is known of how intrinsic epigenetic changes can act to regulate the temporal progression of development. Here we showed that the expression of RABBIT EARS (RBE) represses the transcription of its target, TCP5, through inducing a variety of epigenetic changes at the TCP5 locus. These changes dissipated over a period of days, allowing for eventual activation of TCP5 expression and a concomitant shift from cell division to cell expansion during Arabidopsis petal development. The gradual loss of repressive epigenetic marks at the TCP5 locus represents an internal timing mechanism to temporally control the development of the Arabidopsis petal. [ABSTRACT FROM AUTHOR]

Background and aims: Hakea prostrata (Proteaceae) is a highly phosphorus-use-efficient plant native to southwest Australia. It maintains a high photosynthetic rate at low leaf phosphorus (P) and exhibits delayed leaf greening, a convergent adaptation that increases nutrient-use efficiency. This study aimed to provide broad physiological and gene expression profiles across leaf development, uncovering pathways leading from young leaves as nutrient sinks to mature leaves as low-nutrient, energy-transducing sources. Methods: To explore gene expression underlying delayed greening, we analysed a de novo transcriptome for H. prostrata across five stages of leaf development. Photosynthesis and respiration rates, and foliar pigment, P and nitrogen (N) concentrations were determined, including the division of P into five biochemical fractions. Key results: Transcripts encoding functions associated with leaf structure generally decreased in abundance across leaf development, concomitant with decreases in foliar concentrations of 85% for anthocyanins, 90% for P and 70% for N. The expression of genes associated with photosynthetic function increased during or after leaf expansion, in parallel with increases in photosynthetic pigments and activity, much later in leaf development than in species that do not have delayed greening. As leaves developed, transcript abundance for cytosolic and mitochondrial ribosomal proteins generally declined, whilst transcripts for chloroplast ribosomal proteins increased. Conclusions: There was a much longer temporal separation of leaf cell growth from chloroplast development in H. prostrata than is found in species that lack delayed greening. Transcriptome-guided analysis of leaf development in H. prostrata provided insight into delayed greening as a nutrient-saving strategy in severely phosphorus-impoverished landscapes. [ABSTRACT FROM AUTHOR]

Summary: To play essential roles of manganese (Mn) in plant growth and development, it needs to be transported to different organs and tissues after uptake. However, the molecular mechanisms underlying Mn distribution between different tissues are poorly understood.We functionally characterized a member of rice natural resistance‐associated macrophage protein (NRAMP) family, OsNramp5 in terms of its tissue specificity of gene expression, cell‐specificity of protein localization, phenotypic analysis of leaf growth and response to Mn fluctuations.OsNramp5 is highly expressed in the leaf sheath. Immunostaining revealed that OsNramp5 is polarly localized at the proximal side of xylem parenchyma cells of the leaf sheath. Both the gene expression and protein abundance of OsNramp5 are unaffected by different Mn concentrations. Knockout of OsNramp5 decreased the distribution of Mn to the leaf sheath, but increased the distribution to the leaf blade at both low and high Mn supplies, resulting in reduced growth of leaf sheath. Furthermore, expression of OsNramp5 under the control of root‐specific promoter in osnramp5 mutant complemented Mn uptake, but could not complement Mn distribution to the leaf sheath.These results indicate that OsNramp5 expressed in the leaf sheath plays an important role in unloading Mn from the xylem for the local distribution in rice. [ABSTRACT FROM AUTHOR]

Catalase (CAT) is one of the key enzymes involved in antioxidant defense systems and mainly scavenges H2O2 and plays a vital role in plant growth, development, and various adverse stresses. To date, a systematic study of the CAT gene family in rubber tree has not been reported. In this study, five HbCAT gene family members were identified from the rubber tree genome, and these were mainly clustered into two subfamilies. Gene structure and motif analysis showed that exon-intron and motif patterns were conserved across different plant species. Sequence analysis revealed that HbCAT proteins contain one active catalytic site, one heme-ligand signature sequence, three conserved amino acid residues (His, Tyr, and Asn), and one peroxisome-targeting signal 1 (PTS1) sequence. Fragment duplication is a selection pressure for the evolution of the HbCAT family based on Ka/Ks values. Analysis of cis-acting elements in the promoters indicated that HbCAT gene expression might be regulated by abscisic acid (ABA), salicylic acid (SA), and MYB transcription factors; furthermore, these genes might be involved in plant growth, development, and abiotic stress responses. A tissue-specific expression analysis showed that HbCATs gradually increased with leaf development and were highly expressed in mature leaves. Gene expression profiling exhibited the differential expression of the HbCATs under cold, heat, drought, and NaCl stresses. Our results provide comprehensive information about the HbCAT gene family, laying the foundation for further research on its function in rubber tree. [ABSTRACT FROM AUTHOR]

Twenty-five years ago, a seminal paper demonstrated that warm temperatures increase auxin levels to promote hypocotyl growth in Arabidopsis thaliana. Here we highlight recent advances in auxin-mediated thermomorphogenesis and identify unanswered questions. In the warmth, PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF7 bind the YUCCA8 gene promoter and, in concert with histone modifications, enhance its expression to increase auxin synthesis in the cotyledons. Once transported to the hypocotyl, auxin promotes cell elongation. The meta-analysis of expression of auxin-related genes in seedlings exposed to temperatures ranging from cold to hot shows complex patterns of response. Changes in auxin only partially account for these responses. The expression of many SMALL AUXIN UP RNA (SAUR) genes reaches a maximum in the warmth, decreasing towards both temperature extremes in correlation with the rate of hypocotyl growth. Warm temperatures enhance primary root growth, the response requires auxin, and the hormone levels increase in the root tip but the impacts on cell division and cell expansion are not clear. A deeper understanding of auxin-mediated temperature control of plant architecture is necessary to face the challenge of global warming. [ABSTRACT FROM AUTHOR]

SUMMARY: Vegetative shade causes an array of morphological changes in plants called shade avoidance syndrome, which includes hypocotyl and petiole elongation, leaf hyponasty, reduced leaf growth, early flowering and rapid senescence. Here, we show that loss‐of‐function mutations in HISTONE DEACETYLASE 9 (HDA9) attenuated the shade‐induced hypocotyl elongation in Arabidopsis. However, the hda9 cotyledons and petioles under shade were not significantly different from those in wild‐type, suggesting a specific function of HDA9 in hypocotyl elongation in response to shade. HDA9 expression levels were stable under shade and its protein was ubiquitously detected in cotyledon, hypocotyl and root. Organ‐specific transcriptome analysis unraveled that shade induced a set of auxin‐responsive genes, such as SMALL AUXIN UPREGULATED RNAs (SAURs) and AUXIN/INDOLE‐3‐ACETIC ACIDs (AUX/IAAs) and their induction was impaired in hda9‐1 hypocotyls. In addition, HDA9 binding to loci of SAUR15/65, IAA5/6/19 and ACS4 was increased under shade. The genetic and organ‐specific gene expression analyses further revealed that HDA9 may cooperate with PHYTOCHROME‐INTERACTING FACTOR 4/7 in the regulation of shade‐induced hypocotyl elongation. Furthermore, HDA9 and PIF7 proteins were found to interact together and thus it is suggested that PIF7 may recruit HDA9 to regulate the shade/auxin responsive genes in response to shade. Overall, our study unravels that HDA9 can work as one component of a hypocotyl‐specific transcriptional regulatory machinery that activates the auxin response at the hypocotyl leading to the elongation of this organ under shade. Significance Statement: Loss‐of‐function mutations of HDA9 exhibited short hypocotyl phenotype under shade. The organ‐specific transcriptome analysis indicated that HDA9 is required for activation of auxin response in the hypocotyl upon shade treatment. HDA9 associated with multiple auxin‐responsive gene loci in vivo to regulate shade‐induced hypocotyl elongation, possibly together with PIF7. This study introduces organ‐specific transcriptional regulatory machinery as a potential topic for further research. [ABSTRACT FROM AUTHOR]

Objectives: The objective of this data set was to identify transcriptional networks that control elongation of seedling leaf sheaths in the C4 grass Sorghum bicolor. One motivation was that leaf sheaths are a primary constituent of stems in grass seedlings; therefore, genes that control growth of this organ are important contributors to successful transition from the seedling stage to the mature plant stage and, ultimately, crop success. Since diurnal rhythms contribute to regulation of signaling networks responsible for growth, a time course representing the late afternoon and early evening was anticipated to pinpoint important control genes for stem growth. Ultimately, the expected outcome was discovery of transcript networks that integrate internal and external signals to fine tune leaf sheath growth and, consequently, plant height. Data description: The data set is RNAseq profiling of upper leaf sheaths collected from wild type Sorghum bicolor (BTx623 line) plants at four-hour intervals from 12.5 h after dawn to 20 h after dawn. Global transcript levels in leaves were determined by deep sequencing of mRNA from four individual seedlings at each time point. This data set contains sequences representing the spectrum of mRNAs from individual genes. This data set enables detection of significant changes in gene-level expression caused by the progression of the day from late afternoon to the middle of the night. This data set is useful to identify gene expression networks regulating growth in the leaf sheath, an organ that is a major contributor to the sorghum seedling stem and defines seedling height. [ABSTRACT FROM AUTHOR]

The microRNA miR319 and its target JAW-TCP transcription factors regulate the proliferation-to-differentiation transition of leaf pavement cells in diverse plant species. In young Arabidopsis leaf primordia, JAW-TCPs are detected towards the distal region whereas the major mRNA319-encoding gene MIR319C, is expressed at the base. Little is known about how this complementary expression pattern of MIR319C and JAW-TCPs is generated. Here, we show that MIR319C is initially expressed uniformly throughout the incipient primordia and is later abruptly down-regulated at the distal region, with concomitant distal appearance of JAW-TCPs, when leaves grow to ~100 μm long. Loss of JAW-TCPs causes distal extension of the MIR319C expression domain, whereas ectopic TCP activity restricts MIR319C more proximally. JAW-TCPs are recruited to and are capable of depositing histone H3K27me3 repressive marks on the MIR319C chromatin. JAW-TCPs fail to repress MIR319C in transgenic seedlings where the TCP-binding cis-elements on MIR319C are mutated, causing miR319 gain-of-function-like phenotype in the embryonic leaves. Based on these results, we propose a model for growth patterning in leaf primordia wherein MIR319C and JAW-TCPs repress each other and divide the uniformly growing primordia into distal differentiation zone and proximal proliferation domain. Author summary: Young leaves in Arabidopsis exhibit a characteristic polar growth pattern where cells at the base grow due to continued cell division, while the tip stops growing as the cells exit division and enter differentiation. The MIR319C and its target JAW-TCP genes are expressed in the proximal and the distal domain respectively and are important for maintaining the polar growth pattern. However, it is not known how the complementary expression pattern of MIR319C and JAW-TCP genes is generated when leaves are initiated. Here, we show that MIR319C is expressed ubiquitously during leaf inception and later downregulated at the distal region. This distal loss of MIR319C is marked by an onset of JAW-TCP expression in the same domain. JAW-TCP proteins directly bind to, and downregulate the transcription of, the MIR319C gene to restrict its expression domain towards the base. Disruption of JAW-TCP-binding sites on the MIR319C promoter leads to miR319-overexpression-like phenotype. Together with the knowledge of miR319c-mediated post-transcriptional regulation of JAW-TCPs, we have shown that JAW-TCPs and miR319c mutually repress each other and generate growth polarity in early leaf primordia. [ABSTRACT FROM AUTHOR]

Fatty Acid Desaturase 2 (FAD2) controls the conversion of oleic acids into linoleic acids. Mutations in FAD2 not only increase the high-oleic content, but also repress the leaf growth. However, the mechanism by which FAD2 regulates the growth pathway has not been elucidated in peanut leaves with single-cell resolution. In this study, we isolated fad2 mutant leaf protoplast cells to perform single-cell RNA sequencing. Approximately 24,988 individual cells with 10,249 expressed genes were classified into five major cell types. A comparative analysis of 3495 differentially expressed genes (DEGs) in distinct cell types demonstrated that fad2 inhibited the expression of the cytokinin synthesis gene LOG in vascular cells, thereby repressing leaf growth. Further, pseudo-time trajectory analysis indicated that fad2 repressed leaf cell differentiation, and cell-cycle evidence displayed that fad2 perturbed the normal cell cycle to induce the majority of cells to drop into the S phase. Additionally, important transcription factors were filtered from the DEG profiles that connected the network involved in high-oleic acid accumulation (WRKY6), activated the hormone pathway (WRKY23, ERF109), and potentially regulated leaf growth (ERF6, MYB102, WRKY30). Collectively, our study describes different gene atlases in high-oleic and normal peanut seedling leaves, providing novel biological insights to elucidate the molecular mechanism of the high-oleic peanut-associated agronomic trait at the single-cell level. [ABSTRACT FROM AUTHOR]

Due to the desirable aesthetic performance, zirconia abutments attract tremendous attention in implant related restoration of the anterior zone. However, the inadequate soft tissue integration originated from the inertia surface of zirconia severely limits its application. Fabricating bionic-patterned zirconia abutments is believed to be a promising strategy to solve this puzzle. The main obstacle to fabricating bionic-pattern lies in that conventional zirconia manufacturing technology cannot precisely engineer complex micro-pattern. Notably, modern 3D printing presents a feasible way to obtain various sophisticated topological architecture. In the present study, series of bionic-patterned zirconia were fabricated by 3D printing, simulating lotus leaf, butterfly wings, shark skin, and gecko foot. The features of micro-patterns and quality of 3D printing were systematically characterized. In addition, the effect of various bionic-patterned zirconia on the behaviors of gingival fibroblasts was investigated. Results showed that zirconia with various micro-scale bionic patterns was successfully and precisely fabricated by 3D printing. Among the four types of bionic patterns, the ones that resembled the geckos' feet or lotus leaves were the most recommended topography for cell growth and spreading, while the pattern mimicked shark skin upgraded the expression of fibroblast functional genes including Col-I, Fn, and Itgb- 1 most obviously. The bionic-patterned zirconia can efficiently promote adhesion, proliferation, and related gene expression of gingival fibroblasts, indicating that bionic-patterned zirconia has great potential to promote soft tissue integration. [Display omitted] • Constructing micro-bionic patterns via 3D printing from zirconia slurry was proved to be possible. • The printed bionic-patterned zirconia rendered great potential to enhance soft tissue integration used as dental abutments. • The micro-patterns facilitated proliferation, spreading, and increased the related gene expression of gingival fibroblasts. [ABSTRACT FROM AUTHOR]

Background: NIN-like protein (NLP) transcription factors (TFs) compose a plant-specific gene family whose members play vital roles in plant physiological processes, especially in the regulation of plant growth and the response to nitrate-nitrogen. However, no systematic identification or analysis of the NLP gene family has been reported in alfalfa. The recently completed whole-genome sequence of alfalfa has allowed us to investigate genome-wide characteristics and expression profiles. Results: 53 MsNLP genes were identified from alfalfa and renamed according to their respective chromosome distributions. Phylogenetic analysis demonstrated that these MsNLPs can be classified into three groups on the basis of their conserved domains. Gene structure and protein motif analyses showed that closely clustered MsNLP genes were relatively conserved within each subgroup. Synteny analysis revealed four fragment duplication events of MsNLPs in alfalfa. The ratios of nonsynonymous (Ka) and synonymous (Ks) substitution rates of gene pairs indicated that the MsNLP genes underwent purifying selection during evolution. Examination of the expression patterns of different tissues revealed specific expression patterns of the MsNLP genes in the leaves, indicating that these genes are involved in plant functional development. Prediction of cis-acting regulatory elements and expression profiles further demonstrated that the MsNLP genes might play important roles in the response to abiotic stress and in phytohormone signal transduction processes. Conclusion: This study represents the first genome-wide characterization of MsNLP in alfalfa. Most MsNLPs are expressed mainly in leaves and respond positively to abiotic stresses and hormonal treatments. These results provide a valuable resource for an improved understanding of the characteristics and biological roles of the MsNLP genes in alfalfa. [ABSTRACT FROM AUTHOR]

Plants adapt to high temperature stresses through thermomorphogenesis, a process that includes stem elongation and hyponastic leaf growth. Thermomorphogenesis is gated by the circadian clock through two evening‐expressed clock components, TIMING OF CAB EXPRESSION1 (TOC1) and PSEUDO‐RESPONSE REGULATORS5 (PRR5). These proteins directly interact with and inhibit PHYTOCHROME INTERACTING FACTOR4 (PIF4), a basic helix–loop–helix transcription factor that promotes thermoresponsive growth. PIF4‐mediated thermoresponsive growth is positively regulated by ZEITLUPE (ZTL), a central clock component, but the molecular mechanisms underlying this are poorly understood. Here, we show that ZTL regulates thermoresponsive growth through TOC1 and PRR5. Genetic analyses reveal that ZTL regulates PIF4 activity as well as PIF4 expression. In Arabidopsis thaliana, ztl mutants exhibit highly accumulated TOC1 and PRR5 and unresponsive expression of PIF4 target genes under exposure to high temperatures. Mutations in TOC1 and PRR5 restore thermoactivation of PIF4 target genes and thermoresponsive growth in ztl mutants. We also show that the molecular chaperone heat‐shock protein 90 promotes thermoresponsive growth through the ZTL‐TOC1/PRR5 signaling module. Further, we show that ZTL protein stability is increased at high temperatures. Taken together, our results demonstrate that ZTL‐mediated degradation of TOC1 and PRR5 enhances the sensitivity of hypocotyl growth to high temperatures. Summary statement: A central clock component, ZEITLUPE (ZTL), is known to regulate thermoresponsive growth in Arabidopsis thaliana. However, its underlying mechanism remains poorly understood. This study demonstrates that ZTL regulates PIF4 activity as well as PIF4 expression through TOC1 (TIMING OF CAB EXPRESSION1) and PRR5 (PSEUDO‐RESPONSE REGULATORS5), thereby promoting thermomorphogenesis. [ABSTRACT FROM AUTHOR]

Auxin is well known to stimulate coleoptile elongation and rapid seedling growth in the air. However, its role in regulating rice germination and seedling establishment under submergence is largely unknown. Previous studies revealed that excessive levels of indole‐3‐acetic acid(IAA) frequently cause the inhibition of plant growth and development. In this study, the high‐level accumulation of endogenous IAA is observed under dark submergence, stimulating rice coleoptile elongation but limiting the root and primary leaf growth during anaerobic germination (AG). We found that oxygen and light can reduce IAA levels, promote the seedling establishment and enhance rice AG tolerance. miRNA microarray profiling and RNA gel blot analysis results show that the expression of miR167 is negatively regulated by submergence; it subsequently modulates the accumulation of free IAA through the miR167‐ARF‐GH3 pathway. The OsGH3‐8 encodes an IAA‐amido synthetase that functions to prevent free IAA accumulation. Reduced miR167 levels or overexpressing OsGH3‐8 increase auxin metabolism, reduce endogenous levels of free IAA and enhance rice AG tolerance. Our studies reveal that poor seed germination and seedling growth inhibition resulting from excessive IAA accumulation would cause intolerance to submergence in rice, suggesting that a certain threshold level of auxin is essential for rice AG tolerance. Summary statement: Excessive auxin accumulation negatively affects rice AG. Conversely, oxygen and light significantly reduce IAA levels, promote the seedling establishment during AG, and submergence‐repressed miR167 reduces IAA levels through miR167‐ARF‐GH3 pathway and enhances AG tolerance. [ABSTRACT FROM AUTHOR]

SUMMARY: Natural antisense long non‐coding RNAs (lncNATs) are involved in the regulation of gene expression in plants, modulating different relevant developmental processes and responses to various stimuli. We have identified and characterized two lncNATs (NAT1UGT73C6 and NAT2UGT73C6, collectively NATsUGT73C6) from Arabidopsis thaliana that are transcribed from a gene fully overlapping UGT73C6, a member of the UGT73C subfamily of genes encoding UDP‐glycosyltransferases (UGTs). Expression of both NATsUGT73C6 is developmentally controlled and occurs independently of the transcription of UGT73C6 in cis. Downregulation of NATsUGT73C6 levels through artificial microRNAs results in a reduction of the rosette area, while constitutive overexpression of NAT1UGT73C6 or NAT2UGT73C6 leads to the opposite phenotype, an increase in rosette size. This activity of NATsUGT73C6 relies on its RNA sequence and, although modulation of UGT73C6 in cis cannot be excluded, the observed phenotypes are not a consequence of the regulation of UGT73C6 in trans. The NATsUGT73C6 levels were shown to affect cell proliferation and thus individual leaf size. Consistent with this concept, our data suggest that the NATsUGT73C6 influence the expression levels of key transcription factors involved in regulating leaf growth by modulating cell proliferation. These findings thus reveal an additional regulatory layer on the process of leaf growth. In this work, we characterized at the molecular level two long non‐coding RNAs (NATsUGT73C6) that are transcribed in the opposite direction to UGT73C6, a gene encoding a glucosyltransferase involved in brassinosteroid homeostasis in A. thaliana. Our results indicate that NATsUGT73C6 expression influences leaf growth by acting in trans and by modulating the levels of transcription factors that are involved in the regulation of cell proliferation. Significance Statement: In this work we characterized at the molecular level two long non‐coding RNAs (NATsUGT73C6) that are transcribed in the opposite direction to UGT73C6, a gene encoding a glucosyltransferase involved in brassinosteroid homeostasis in Arabidopsis thaliana. Our results indicate that NATsUGT73C6 expression influences leaf growth by acting in trans and by modulating the levels of transcription factors that are involved in the regulation of cell proliferation. [ABSTRACT FROM AUTHOR]

The effects of Olea europaea leaf extract (OLE) phenolics, including oleuropein (OL), hydroxytyrosol (HT), tyrosol (TYR), and rutin against glioblastoma (GB), independently and in combination with temozolomide (TMZ), were investigated in T98G and A172 cells. Cell growth was assessed by WST-1, real-time cell analysis, colony formation, and cell cycle distribution assays. A dual acridine orange propidium iodide (AO/PI) staining and annexin V assay determined cell viability. A sphere-forming assay, an intracellular oxidative stress assay, and the RNA expression of CD133 and OCT4 investigated the GB stem-like cell (GSC) phenotype. A scratch wound-healing assay evaluated migration capacity. OL was as effective as OLE in terms of apoptosis promotion (p < 0.001) and GSC inhibition (p < 0.001). HT inhibited cell viability, GSC phenotype, and migration rate (p < 0.001), but its anti-GB effect was less than the total effect of OLE alone. Rutin decreased reactive oxygen species production and inhibited colony formation and cell migration (p < 0.001). TYR demonstrated the least effect. The additive effects of OL, HT, TYR and rutin with TMZ were significant (p < 0.001). Our data suggest that OL may represent a novel therapeutic approach against GB cells, while HT and rutin show promise in increasing the efficacy of TMZ therapy. [ABSTRACT FROM AUTHOR]

Expansins are cell‐wall loosening proteins involved in plant cell expansion and elongation. Objectives of this study were to identify expansins related to leaf elongation in a perennial grass species and determine the relationship between the expression of expansin genes and leaf elongation. A total of 20 expansin genes were identified in tall fescue (Festuca arundinacea), out of which nine genes belonged to the EXPA‐ and 11 to the EXPB subfamily. Two genotypes ("TF007" and "TF116") with different growth rates were used to determine the correlation between expansins and leaf growth. Among the 20 expansins, 16 were differentially expressed in the leaf growth zone in "TF007" and "TF116." The further analysis of gene expression in different leaf segments of "TF007" and "TF116" revealed that the expression level of FaEXPB16 was positively correlated with leaf elongation rate, and "TF007" had a higher leaf elongation rate than "TF116" due to the greater expression level of FaEXPB16. FaEXPA7 exhibited significantly higher expression level in leaves of the rapid‐growing genotypes than the slow‐growing genotypes, suggesting that FaEXPA7 acts as a positive regulator for leaf elongation. FaEXPA7 also exhibited its highest expression level in the cell division zone located in the leaf base. FaEXPB3, FaEXPB4‐2, and FaEXPB11‐2 showed a negative correlation with the leaf elongation rate in "TF007" and "TF116" and were highly expressed in leaves of the slow‐growing genotypes. As promoting or repressing factors for leaf growth, these five expansins could be used as candidate genes in developing the rapid or slow‐growing perennial grass species. [ABSTRACT FROM AUTHOR]

The presence of crinkly (local bulges) on the leaf surface of Chinese cabbage is a typical characteristic to distinguish different Chinese cabbage cultivars. Previously, the studies on leaf development regulation genes are mostly focused on model plants. However, the studies on crinkly leaves of Chinese cabbage are relatively lagging. To understand the mechanisms of local bulges formation, two leaf surfaces with significant difference inbred lines T599 and Y317 were used. The content of multiple phytohormones and the differentially expressed genes among the crinkly and flat leaves of T599 (T599C and T599F) and the flat leaves of Y317 (Y317F) were analyzed using RNA-seq method. The results showed that the content of IAA, TZR, Zeatin, IPA, GA1 and GA3 were higher in crinkly leaves than that in flat leaves. Through RNA-seq, total 1.708 DEGs and 4.791 DEGs were identified from T599C vs. T599F and T599C vs. Y317F, respectively, and among them, 488 common DEGs with similar expression trend between crinkly and flat leaves were further identified. Additionally, analysis of the common DEGs expression pattern suggests transcription factors, plant hormones biosynthesis and signal transduction, plant growth and development, and cell wall biosynthesis and degradation might play a critical role in regulating the crinkly formation on the leaf surface of Chinese cabbage. Our study provides new insight into phytohormones and the regulatory network of gene expression in the crinkly leaves and flat leaves of Chinese cabbage. These response genes may be used for further strategy development of Chinese cabbage cultivars with leaf flatness. [ABSTRACT FROM AUTHOR]

We evaluated the effect of dietary supplementation with Moringa oleifera leaf extract on the resistance to Aeromonas hydrophila infection in crucian carp. The fish were randomly divided into five groups: the basal diet, the basal diet supplied with 0.25% (0.25 M), 0.5% (0.5 M), 0.75% (0.75 M) and 1.0% M. oleifera leaf extract (1.0 M) for 8 weeks. The growth, antioxidant capabilities, related immune genes as well as resistance to A. hydrophila infection were determined. The results showed that compared with the control group, the weight gain, specific growth rate in the group of 0.5% M. oleifera leaf extract, serum superoxide dismutase (SOD), albumin (ALB) and glutathione peroxidase (GSH-Px), the gene expression of hepatopancreas BTB and CNC homolog 1 (Bach1), NF-E2-related factor 2 (Nrf2), peroxidases (PRX) and NADPH oxidase (NOX) in the group of 0.5%–1.0% M. oleifera leaf extract increased, while feed conversion ratio, serum cortisol, red blood cell (RBC), alanine aminotransferase (ALT), malonaldehyde (MDA) decreased in the group of 0.5%–1.0% M. oleifera leaf extract before the stress. After the infection, the group of 0.5% or 0.75% M. oleifera leaf extract also could improve the serum ALB, hepatopancreas Kelch-like-ECH-associated protein 1 (Keap1), Bach1 , Nrf2 , TOR , PRX and NOX and reduce cortisol compared with the control group. In summary, this study suggested that 0.5% M. oleifera leaf extract inclusion increased the growth performance, even had positive effects on physiological and immune function, and enhanced resistance against pathogenic infections in crucian carp. The optimum level of M. oleifera leaf extract for crucian carp was estimated to be 0.35%–0.48% based on polynomial comparison with FCR and SGR. • oleifera leaf extract has the potential to improve the growth of crucian carp. • oleifera leaf extract has the potential to improve resistance of bacteria pathogen. • oleifera leaf extract has the potential to immune and anti-oxidative ability. • oleifera leaf extract has the potential to up-regulate immune related genes of crucian carp. [ABSTRACT FROM AUTHOR]

Plant polyploidization changes its leaf morphology and leaf development patterns. Understanding changes in leaf morphology and development patterns is a prerequisite and key to studying leaf development in polyploid plants. In this study, we quantified and analyzed the differences in leaf morphology, leaf growth polarity, and leaf size between diploid and tetraploid birches (Betula pendula subsp. pendula), and preliminarily investigated genes involved in leaf growth and development in birch. The results showed significant changes in leaf morphology in tetraploid birches, especially the basal part of the leaf. In addition, the proximal growth rate of tetraploid leaves was altered. The changed proximal growth rate did not affect the growth polarity pattern of tetraploid leaves. The leaf area of tetraploid was significantly larger than that of diploid birch. The difference in leaf size was mainly due to differences in their growth rates in the middle and late stages of leaf development. Increased cell expansion capacity was the major reason for the enormous leaves of tetraploid birch; however, cell proliferation did not contribute to the larger tetraploid leaf. The gene expression of ATHB12 was associated with cell size and leaf area, and may be a critical gene affecting the leaf size in diploid and tetraploid birches. The results will provide valuable insights into plant polyploid leaf development and a theoretical basis for later investigations into the molecular mechanisms underlying the gigantism of tetraploid birch leaves. [ABSTRACT FROM AUTHOR]

As an important agronomic trait in rice (Oryza sativa), moderate leaf rolling helps to maintain the erectness of leaves and minimize shadowing between leaves, leading to improved photosynthetic efficiency and grain yield. However, the molecular mechanisms underlying rice leaf rolling still need to be elucidated. Here, we isolated a rice mutant, rl89, showing adaxially rolled leaf phenotype due to decreased number and size of bulliform cells. We confirmed that the rl89 phenotypes were caused by a single nucleotide substitution in OsDRB2 (LOC_Os10g33970) gene encoding DOUBLE-STRANDED RNA-BINDING2. This gene was constitutively expressed, and its encoded protein was localized to both nucleus and cytoplasm. Yeast two-hybrid assay showed that OsDRB2 could interact with DICER-LIKE1 (DCL1) and OsDRB1-2 respectively. qRT-PCR analysis of 29 related genes suggested that defects of the OsDRB2-miR166-OsHBs pathway could play an important role in formation of the rolled leaf phenotype of rl89, in which OsDRB2 mutation reduced miR166 accumulation, resulting in elevated expressions of the class III homeodomain-leucine zipper genes (such as OsHB1, 3 and 5) involved in leaf polarity and/or morphology development. Moreover, OsDRB2 mutation also reduced accumulation of miR160, miR319, miR390, and miR396, which could cause the abnormal leaf development in rl89 by regulating expressions of their target genes related to leaf development. [ABSTRACT FROM AUTHOR]

Plant AT-rich sequence and zinc-binding (PLATZ) proteins are a class of plant-specific transcription factor that play a crucial role in plant growth, development, and stress response. However, the evolutionary relationship of the PLATZ gene family across the Populus genus and the biological functions of the PLATZ protein require further investigation. In this study, we identified 133 PLATZ genes from six Populus species belonging to four Populus sections. Synteny analysis of the PLATZ gene family indicated that whole genome duplication events contributed to the expansion of the PLATZ family. Among the nine paralogous pairs, the protein structure of PtrPLATZ14/18 pair exhibited significant differences with others. Through gene expression patterns and co-expression networks, we discovered divergent expression patterns and sub-networks, and found that the members of pair PtrPLATZ14 / 18 might play different roles in the regulation of macromolecule biosynthesis and modification. Furthermore, we found that PtrPLATZ14 regulates poplar leaf development by affecting cell size control genes PtrGRF / GIF and PtrTCP. In conclusion, our study provides a theoretical foundation for exploring the evolution relationships and functions of the PLATZ gene family within Populus species and provides insights into the function and potential mechanism of PtrPLATZ14 in leaf morphology that were diverse across the Populus genus. [ABSTRACT FROM AUTHOR]

Shaded plants challenged with herbivores or pathogens prioritize growth over defense. However, most experiments have focused on the effect of shading light cues on defense responses. To investigate the potential interaction between shade-avoidance and wounding-induced Jasmonate (JA)-mediated signaling on leaf growth and movement, we used repetitive mechanical wounding of leaf blades to mimic herbivore attacks. Phenotyping experiments with combined treatments on Arabidopsis thaliana rosettes revealed that shade strongly inhibits the wound effect on leaf elevation. By contrast, petiole length is reduced by wounding both in the sun and in the shade. Thus, the relationship between the shade and wounding/JA pathways varies depending on the physiological response, implying that leaf growth and movement can be uncoupled. Using RNA-sequencing, we identified genes with expression patterns matching the hyponastic response (opposite regulation by both stimuli, interaction between treatments with shade dominating the wound signal). Among them were genes from the PKS (Phytochrome Kinase Substrate) family, which was previously studied for its role in phototropism and leaf positioning. Interestingly, we observed reduced shade suppression of the wounding effect in pks2pks4 double mutants while a PKS4 overexpressing line showed constitutively elevated leaves and was less sensitive to wounding. Our results indicate a trait-specific interrelationship between shade and wounding cues on Arabidopsis leaf growth and positioning. Moreover, we identify PKS genes as integrators of external cues in the control of leaf hyponasty further emphasizing the role of these genes in aerial organ positioning. Author summary: Plants face different types of stressful situations without the ability to relocate to favorable environments. For example, increasing plant density reduces access to sunlight as plants start to shade each other. Foliar shading represents a stress that many plants cope with by changing their morphology. This includes elongation of stem-like structures and repositioning of leaves to favor access to unfiltered sunlight. Plants also defend themselves against various pathogens including herbivores. Defense mechanisms include the production of deterrent chemical and morphological adaptations such as stunted growth and downwards leaf repositioning. Here we studied the morphological response of plants when simultaneously facing shade and herbivore stress. When facing both stresses petiole growth was intermediate between the shade-enhanced and wound-repressed response. In contrast, the shade cue overrides the wounding cue leading to a similar upwards leaf repositioning in the combined treatments or in the response to shade alone. Using gene expression analyses and genetics we identified two members of the Phytochrome Kinase Substrate family as playing a signal integration role when plants simultaneously faced both stresses. This contributes to our understanding of the mechanisms underlying plant morphological adaptations when facing multiple stresses. [ABSTRACT FROM AUTHOR]

Domains of unknown function (DUF) proteins represent a large group of uncharacterized protein families. The DUF868 gene family in Nicotiana has not yet been described. In the present study, we identified 12, 11, and 25 DUF868 family members in the genome of Nicotiana sylvestris , N. tomentosiformis , and N. tabacum , respectively. Based on phylogenetic analysis, these were categorized into five groups (A-E). Within each group, the gene structures, motifs, and tertiary structures showed high similarity. NtDUF868 family expansion during evolution was mainly driven by segmental duplication events. MicroRNA (miRNA) target site prediction identified 12 miRNA members that target 16 NtDUF868 family genes. The promoters of these genes contain cis -regulatory elements responsive to light, phytohormones, and abiotic stresses. Expression profiling revealed their tissue- and stage-specific expression patterns. RNA-sequencing and quantitative reverse transcription PCR revealed that the NtDUF868 family genes are potentially involved in the response to abiotic and biotic stresses, particularly drought and hormone stresses, and in the resistance to black shank and bacterial wilt. We generated transformed plants using NtDUF868-E5 overexpression and gene-editing vectors. NtDUF868-E5 overexpression resulted in enhanced tobacco plant growth and development, leading to increased leaf photosynthetic capacity and higher chlorophyll and carotenoid contents. This study provided a comprehensive genome-wide analysis of the DUF868 gene family, shedding light on their potential roles in plant growth and stress responses. [Display omitted] • 12, 11, and 25 DUF868 were identified from Nicotiana sylvestris , N. tomentosiformis , and N. tabacum , respectively, and systematically analyzed. • NtDUF868 gene family show their tissue and stage-specific expression patterns and play potential roles in response to abiotic and biotic stresses. • NtDUF868-E5 overexpression can promote tobacco growth and development, improve leaf photosynthetic capacity, and increase chlorophyll and carotenoids contents. [ABSTRACT FROM AUTHOR]

Cytokinin response factors (CRFs) are transcription factors (TFs) that are specific to plants and have diverse functions in plant growth and stress responses. However, the precise roles of CRFs in regulating tomato plant architecture and leaf development have not been comprehensively investigated. Here, we identified a novel CRF, SlCRF6 , which is involved in the regulation of plant growth via the gibberellin (GA) signaling pathway. SlCRF6 -overexpressing (SlCRF6 -OE) plants displayed pleiotropic phenotypic changes, including reduced internode length and leaf size, which caused dwarfism in tomato plants. This dwarfism could be alleviated by application of exogenous GA 3. Remarkably, quantitative real-time PCR (qRT PCR), a dual luciferase reporter assay and a yeast one-hybrid (Y1H) assay revealed that SlCRF6 promoted the expression of SlDELLA (a GA signal transduction inhibitor) in vivo. Furthermore, transgenic plants displayed variegated leaves and diminished chlorophyll content, resulting in decreased photosynthetic efficiency and less starch than in wild-type (WT) plants. The results of transient expression assays and Y1H assays indicated that SlCRF6 suppressed the expression of SlPHAN (leaf morphology-related gene). Collectively, these findings suggest that SlCRF6 plays a crucial role in regulating tomato plant morphology, leaf development, and the accumulation of photosynthetic products. • SlCRF6 overexpression lines exhibit dwarfism with shorter internodes and smaller leaf. • SlCRF6 responds to exogenous GA 3 treatment and affects the endogenous GA 3 content. • Leaf defects in SlCRF6 -OE lines lead to reduced photosynthetic efficiency, ultimately affecting plant growth. • SlCRF6 affects plant growth in tomato by regulating SlDELLA and SlPHAN. [ABSTRACT FROM AUTHOR]

SUMMARY: The characterization of the genetic basis of maize (Zea mays) leaf development may support breeding efforts to obtain plants with higher vigor and productivity. In this study, a mapping panel of 197 biparental and multiparental maize recombinant inbred lines (RILs) was analyzed for multiple leaf traits at the seedling stage. RNA sequencing was used to estimate the transcription levels of 29 573 gene models in RILs and to derive 373 769 single nucleotide polymorphisms (SNPs), and a forward genetics approach combining these data was used to pinpoint candidate genes involved in leaf development. First, leaf traits were correlated with gene expression levels to identify transcript–trait correlations. Then, leaf traits were associated with SNPs in a genome‐wide association (GWA) study. An expression quantitative trait locus mapping approach was followed to associate SNPs with gene expression levels, prioritizing candidate genes identified based on transcript–trait correlations and GWAs. Finally, a network analysis was conducted to cluster all transcripts in 38 co‐expression modules. By integrating forward genetics approaches, we identified 25 candidate genes highly enriched for specific functional categories, providing evidence supporting the role of vacuolar proton pumps, cell wall effectors, and vesicular traffic controllers in leaf growth. These results tackle the complexity of leaf trait determination and may support precision breeding in maize. Significance Statement: Innovative genomics‐ and transcriptomics‐based forward genetic approaches can improve our understanding of the molecular basis of leaf development in maize (Zea mays). By combining transcript–trait correlations, genome‐wide associations, and expression quantitative trait locus mapping, we identified 25 candidate genes that may have a key role in early leaf growth. [ABSTRACT FROM AUTHOR]

Plants have evolved to grow under prominently fluctuating environmental conditions. In experiments under controlled conditions, temperature is often set to artificial, binary regimes with constant values at day and at night. This study investigated how such a diel (24 hr) temperature regime affects leaf growth, carbohydrate metabolism and gene expression, compared to a temperature regime with a field‐like gradual increase and decline throughout 24 hr. Soybean (Glycine max) was grown under two contrasting diel temperature treatments. Leaf growth was measured in high temporal resolution. Periodical measurements were performed of carbohydrate concentrations, carbon isotopes as well as the transcriptome by RNA sequencing. Leaf growth activity peaked at different times under the two treatments, which cannot be explained intuitively. Under field‐like temperature conditions, leaf growth followed temperature and peaked in the afternoon, whereas in the binary temperature regime, growth increased at night and decreased during daytime. Differential gene expression data suggest that a synchronization of cell division activity seems to be evoked in the binary temperature regime. Overall, the results show that the coordination of a wide range of metabolic processes is markedly affected by the diel variation of temperature, which emphasizes the importance of realistic environmental settings in controlled condition experiments. Dynamically changing temperature affects soybean leaf growth and regulatory mechanisms in non‐intuitive ways. The results may help improving knowledge transfer between experiments performed under controlled conditions and experiments performed in the field. [ABSTRACT FROM AUTHOR]

Aralia elata (Miq.) Seem is widely used as a medicinal plant and functional food in China. In this study, A. elata plants were exposed to full sunlight (CK), 40% shading (LS), 60% shading (MS), and >80% shading (ES) condition to investigate the effects of shading treatments on growth, stress levels, antioxidant enzymes activity, araloside content and related gene expression. The greatest growth and leaf biomass were achieved in 40% shading, and leaf biomass per plant increased by 16.09% compared to the non-shading treatment. Furthermore, the lowest reactive oxide species (ROS) production and lipid peroxidation resulting from increasing antioxidant enzyme activity were also observed in LS treatment. Overall, shading percentage negatively regulated the expression of key enzymes (squalene synthase, SS; squalene epoxidase, SE and β-amyrin synthase, bAS) involved in the saponin biosynthesis, resulting in the greatest yields of total and four selected aralosides in A. elata leaves were achieved in sunlight group. However, the greatest yield of total saponin in the leaves was observed in the 40% shading group due to higher leaf biomass. The results suggest that optimizing the field growing conditions would be important for obtaining the greatest yield of bioactive components. Total saponin and selected aralosides also have a significant correlation with ROS production and antioxidant enzyme activity, these indicated the increased yield of these saponins may be part of a defense response. The study concludes that the production of saponin was the interaction of oxidative stress and photosynthesis. • Aralia. elata was a typical shade plant suitable to grow under lower light shading (40% shading). • Higher light irradiation stimulated triterpene saponin accumulation and related genes expression. • The production of triterpene saponin was the interaction of oxidative stress and photosynthesis. [ABSTRACT FROM AUTHOR]

Leaf senescence is a prominent symptom of heat injury observed in cool-season plants. The application of melatonin (MT) and inoculation with mycorrhizal fungi can mitigate heat-induced leaf senescence. The current research aims to examine the individual and combined effects of arbuscular mycorrhizal (AM) inoculation and MT application on heat-related leaf senescence in perennial ryegrass (Lolium perenne L.). In addition, whether the effects of these treatments were in any way associated with abscisic acid (ABA), gibberellin (GA), and cytokinin (CTK) for exerting the bioactivity. According to the results, the suppression of heat-mediated leaf senescence using MT treatment and AM inoculation manifested as increased photosynthesis, turf quality (TQ), and plant growth, and reduced membrane lipid peroxidation levels as well as the chlorophyll catabolic genes (CCGs) and senescence-associated genes (LpSAG12.1 and Lph36) transcript levels in the heat-stressed plants. MT application and AM inoculation elevated the internal MT, GA, and CTK levels, while reducing the ABA levels in the heat-stressed plants. In addition, the MT biosynthesis genes (LpTDC1 , LpTDC2 , LpCOMT1 , LpASMT1 , and LpASMT3), the ABA catabolic gene, the GA biosynthesis genes, CTK biosynthesis genes, along with the associated signal transduction response transcription factors (TFs) (type-B ARRs) exhibited increased levels, whereas the expressions of the GA and CTK catabolic genes and the biosynthesis and signal transduction genes related to ABA exhibited decreased levels after MT application and AM inoculation in the heat-stressed plants. Furthermore, the application of exogenous MT notably elevated the AM colonization rate at high temperature (HT) condition. After 28 days of heat stress, compared to the treatment with neither AMF nor MT application, AM combined with MT achieved a synergistic effect, resulting in a 25.32%, 87.21%, 58.69%, 57.17%, and 28.46% increase in TQ, leaf chlorophyll content, net photosynthesis (Pn), leaf photochemical efficiency (Fv/Fm), and relative water content (RWC), respectively, in perennial ryegrass. Additionally, this treatment significantly reduced the electrolyte leakage (EL), hydrogen peroxide (H 2 O 2) and malondialdehyde (MDA) levels by 30.76%, 38.19%, and 31.95%, respectively, and also significantly reduced the transcription levels of CCGs and senescence-associated genes. Consequently, it was inferred that a combination of AM and MT treatments promotes plant growth and development and suppresses heat-induced leaf senescence in plants. • Heat stress induces leaf senescence and inhibits the growth of perennial ryegrass. • AMF and melatonin had synergistic effect on suppressing heat-induced leaf senescence. • AM symbiosis and melatonin down-regulated chlorophyll-degradation genes suppressing senescence. • AM symbiosis and melatonin up-regulated genes for CTK, GA and MT signaling and responses. • AM symbiosis and melatonin down-regulated genes for ABA signaling and responses. [ABSTRACT FROM AUTHOR]

Tea plants (Camellia sinensis) typically contain high-flavonoid phytochemicals like catechins. Recently, new tea cultivars with unique purple-colored leaves have gained attention. These purple tea cultivars are enriched with anthocyanin, which provides an interesting perspective for studying the metabolic flux of the flavonoid pathway. An increasing number of studies are focusing on the leaf color formation of purple tea and this review aims to summarize the latest progress made on the composition and accumulation of anthocyanins in tea plants. In addition, the regulation mechanism in its synthesis will be discussed and a hypothetical regulation model for leaf color transformation during growth will be proposed. Some novel insights are presented to facilitate future in-depth studies of purple tea to provide a theoretical basis for targeted breeding programs in leaf color. • Natural mutant purple tea provides new insights into flavonoid metabolic flux flow. • The controversy over anthocyanin components and determination methods in tea plants was discussed. • Summarised omics data in gene and transcription factor expression in tea anthocyanin biosynthesis. • Overviewed the internal and external factors that influence anthocyanin biosynthesis in tea plants. • A prediction model of color transformation with leaf growth was summarized. [ABSTRACT FROM AUTHOR]

How genetically regulated growth shapes organ form is a key problem in developmental biology. Here, we investigate this problem using the leaflet-bearing complex leaves of Cardamine hirsuta as a model. Leaflet development requires the action of two growth-repressing transcription factors: REDUCED COMPLEXITY (RCO), a homeodomain protein, and CUP-SHAPED COTYLEDON2 (CUC2), a NAC-domain protein. However, how their respective growth-repressive actions are integrated in space and time to generate complex leaf forms remains unknown. By using live imaging, we show that CUC2 and RCO are expressed in an interspersed fashion along the leaf margin, creating a distinctive striped pattern. We find that this pattern is functionally important because forcing RCO expression in the CUC2 domain disrupts auxin-based marginal patterning and can abolish leaflet formation. By combining genetic perturbations with time-lapse imaging and cellular growth quantifications, we provide evidence that RCO -mediated growth repression occurs after auxin-based leaflet patterning and in association with the repression of cell proliferation. Additionally, through the use of genetic mosaics, we show that RCO is sufficient to repress both cellular growth and proliferation in a cell-autonomous manner. This mechanism of growth repression is different to that of CUC2 , which occurs in proliferating cells. Our findings clarify how the two growth repressors RCO and CUC2 coordinate to subdivide developing leaf primordia into distinct leaflets and generate the complex leaf form. They also indicate different relationships between growth repression and cell proliferation in the patterning and post-patterning stages of organogenesis. [Display omitted] • CUC2 and RCO are expressed in an interspersed pattern in C. hirsuta complex leaves • This interspersed expression is required for complex leaf development • RCO limits both cell proliferation and cellular growth in a cell-autonomous manner • The cellular parameters for growth repression by CUC2 and RCO are distinct Bhatia et al. use time-lapse imaging, genetic perturbations, and cellular growth analysis to show that spatially separated growth-repressive activities of CUC2 and RCO shape C. hirsuta complex leaf form. They find different relationships between cell proliferation and growth repression during patterning and post-patterning stages of organogenesis. [ABSTRACT FROM AUTHOR]

A 60‐day feeding trial was conducted to evaluate the effects of feeding Houttuynia cordata leaf meal and extract on the growth performance, nutrient utilization and expression of insulin‐like growth factor‐I (IGF‐I) in Labeo rohita fingerlings. Two hundred seventy fingerlings were randomly distributed in six experimental groups in triplicates. Six isonitrogenous (350 g/kg CP) and isocaloric (17 MJ/kg DE) diets were prepared with graded levels of leaf meal (LM) and leaf extract (LE), namely C (control, without LE and LM), LE‐0.25 (2.5 g/kg LE), LE‐0.5 (5 g/kg LE), LE‐1.0 (10 g/kg LE), LM‐1.0 (10 g/kg LM) and LM‐2.0 (20 g/kg LM). Significantly (p < 0.05) higher IGF‐I expression, weight gain %, specific growth rate and lower feed conversion ratio were observed in LM‐1.0 followed by LE‐1.0 group compared to control group. Higher protease activity was observed in LE‐1.0 compared to other experimental groups, while no significant changes were found for amylase and lipase activities. Compared to control, muscle alanine aminotransferase and aspartate aminotransferase activities were significantly higher in treatment groups except for LM‐2.0. These results suggest that either LE‐1.0 or LM‐1.0 can be supplemented in the diet to improve the growth of L. rohita. However, the supplementation of 10 g H. cordata leaf meal/kg feed can be the better option considering the cost of extraction. [ABSTRACT FROM AUTHOR]

Boundary domains play important roles during morphogenesis in plants and animals, but how they contribute to patterning and growth coordination in plants is not understood. The CUC genes determine the boundary domains in the aerial part of the plants and, in particular, they have a conserved role in regulating leaf complexity across Angiosperms. Here, we used tooth formation at the Arabidopsis leaf margin controlled by the CUC2 transcription factor to untangle intertwined events during boundary-controlled morphogenesis in plants. Combining conditional restoration of CUC2 function with morphometrics as well as quantification of gene expression and hormone signaling, we first established that tooth morphogenesis involves a patterning phase and a growth phase. These phases can be separated, as patterning requires CUC2 while growth can occur independently of CUC2. Next, we show that CUC2 acts as a trigger to promote growth through the activation of three functional relays. In particular, we show that KLUH acts downstream of CUC2 to modulate auxin response and that expressing KLUH can compensate for deficient CUC2 expression during tooth growth. Together, we reveal a genetic and molecular network that allows coordination of patterning and growth by CUC2-defined boundaries during morphogenesis at the leaf margin. [ABSTRACT FROM AUTHOR]

Highlights • Leaf expansion rate (LER) of maize increased along with an increase in temperatureunder low evaporative demand conditions. • Under high evaporative demand conditions, LER reduced at 32 °C due to high VPD. • Stomatal conductance, photosynthesis, and transpiration mirrored the response of LER. • Stomatal traits were affected by VPD. • The response of LER in maize was associated with the differential expression of genes related to leaf development and expansion. Abstract Leaf area affects light interception, carbon assimilation and plant growth. How maize leaf development and expansion is affected by temperature under different evaporative demand conditions is not well understood. Effects of three temperatures (21, 27 and 32 °C) under high and low evaporative demand conditions were tested in growth chambers. Leaf expansion rate (LER), leaf appearance rate (LAR), leaf number, plant height, photosynthesis (A), net assimilation rate (NAR), stomatal conductance (gs), and transpiration (E) increased with increasing temperature under low evaporative demand environments. Under high evaporative demand, while there was an increase with temperature until 27 °C, at 32 °C there was a decrease in LER, plant height, A, NAR, gs, and E. However, the variation in the rate of leaf appearance appears to be linked to temperature but not VPD. The development of stomata and epidermal cells were affected by VPD with large size stomata and more epidermal cells under low VPD. The differential responses of LER to low and high evaporative demands could be attributed to changes in expression of Expansin A2, A4, and B1 genes and XTH23. The significant effect of temperature and VPD on the expression of vacuolar H + pyrophosphatase and teosinte branched gene was detected. Overall, we found a negative effect of high VPD due to high evaporative demand for maize leaf expansion and development. [ABSTRACT FROM AUTHOR]

Leaf growth is a complex process that involves the action of diverse transcription factors (TFs) and their downstream gene regulatory networks. In this study, we focus on the functional characterization of the Arabidopsis thaliana TF GROWTH-REGULATING FACTOR9 (GRF9) and demonstrate that it exerts its negative effect on leaf growth by activating expression of the bZIP TF OBP3-RESPONSIVE GENE 3 (ORG3). While grf9 knockout mutants produce bigger incipient leaf primordia at the shoot apex, rosette leaves and petals than the wild type, the sizes of those organs are reduced in plants overexpressing GRF9 (GRF9ox). Cell measurements demonstrate that changes in leaf size result from alterations in cell numbers rather than cell sizes. Kinematic analysis and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay revealed that GRF9 restricts cell proliferation in the early developing leaf. Performing in vitro binding site selection, we identified the 6-base motif 5'-CTGACA-3' as the core binding site of GRF9. By global transcriptome profiling, electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) we identified ORG3 as a direct downstream, and positively regulated target of GRF9. Genetic analysis of grf9 org3 and GRF9ox org3 double mutants reveals that both transcription factors act in a regulatory cascade to control the final leaf dimensions by restricting cell number in the developing leaf. [ABSTRACT FROM AUTHOR]

The effect and function mechanism of maleic hydrazide on the growth of mature leaves is unclear. Duckweed is widely used as a model plant to study the effect of compounds on plant growth. The observation of section and ultrastructure of the fronds, the comparation of SOD enzyme activity and related-gene transcriptional expression level showed that 75 μg/mL maleic hydrazide could prompt the growth of the mother fronds in S. Polyrriza 7498. The half-mother fronds (without meristematic tissue, cut from the mother fronds) with little meristematic tissue could repair themselves and delay their senescence by 75 μg/mL MH. The mother fronds turned more greener with 50 μg/mL MH and exogenous 0.1 μmol/L 6-BA (a kind of cytokinin) treatment, as well as with the increasing of fresh and dry weight in S. Polyrriza 7498. RNA-Seq data found that the happy growth of the mother fronds caused by MH, was probably resulted from up-regulating the expression of gene related to the synthesis and signaling transduction of cytokinin in S. Polyrriza 7498. Which are responsible for the maintaining membrane system integrate and transport protein function. The work gives lights to the study of function mechanism of MH prompting mature leaves growth and delaying mature leaves senescence in plant. And it provides a strategy to increase biomass with the application of low concentration MH and 6-BA in the same time in agriculture. • MH combined with cytokinin could inhibit the growth of shoots, promoting the growth of mature leaves in plant. The biomass could be increased in crops with the application of MH and cytokinin at a suitable concentration and time. [ABSTRACT FROM AUTHOR]

Organ size control is of particular importance for developmental biology and agriculture, but the mechanisms underlying organ size regulation remain elusive in plants. Meristemoids, which possess stem cell-like properties, have been recognized to play important roles in leaf growth. We have recently reported that the Arabidopsis F-box protein STERILE APETALA (SAP)/SUPPRESSOR OF DA1 (SOD3) promotes meristemoid proliferation and regulates organ size by influencing the stability of the transcriptional regulators PEAPODs (PPDs). Here we demonstrate that KIX8 and KIX9, which function as adaptors for the corepressor TOPLESS and PPD, are novel substrates of SAP. SAP interacts with KIX8/9 and modulates their protein stability. Further results show that SAP acts in a common pathway with KIX8/9 and PPD to control organ growth by regulating meristemoid cell proliferation. Thus, these findings reveal a molecular mechanism by which SAP targets the KIX-PPD repressor complex for degradation to regulate meristemoid cell proliferation and organ size. [ABSTRACT FROM AUTHOR]

Here we report the discovery through activation tagging and subsequent characterization of the BIG LEAF (BL) gene from poplar. In poplar, BL regulates leaf size via positively affecting cell proliferation. Up and downregulation of the gene led to increased and decreased leaf size, respectively, and these phenotypes corresponded to increased and decreased cell numbers. BL function encompasses the early stages of leaf development as native BL expression was specific to the shoot apical meristem and leaf primordia and was absent from the later stages of leaf development and other organs. Consistently, BL downregulation reduced leaf size at the earliest stages of leaf development. Ectopic expression in mature leaves resulted in continued growth most probably via sustained cell proliferation and thus the increased leaf size. In contrast to the positive effect on leaf growth, ectopic BL expression in stems interfered with and significantly reduced stem thickening, suggesting that BL is a highly specific activator of growth. In addition, stem cuttings from BL overexpressing plants developed roots, whereas the wild type was difficult to root, demonstrating that BL is a positive regulator of adventitious rooting. Large transcriptomic changes in plants that overexpressed BL indicated that BL may have a broad integrative role, encompassing many genes linked to organ growth. We conclude that BL plays a fundamental role in control of leaf size and thus may be a useful tool for modifying plant biomass productivity and adventitious rooting. [ABSTRACT FROM AUTHOR]

This study evaluated the effects of Bougainvillea glabra (BG) leaf as a feed supplement on growth, skin mucosal immune parameters, serum oxidative stress, expression of immune-related genes, and susceptibility to pathogen infection in carp Cyprinus carpio. Diets containing four different BG concentrations (g kg−1), i.e., 0 g (basal diet), 20 g (BG20), 30 g (BG30), 40 g (BG40), and 50 g (BG50), were fed to the carp (average weight: 14.03 ± 0.81 g) for 8 weeks. Skin mucosal immunological and serum antioxidant parameters were examined 8 weeks post-feeding. Growth performance was significantly higher in BG40. Among the examined skin mucosal immune parameters, lysozyme (33.79 ± 0.98 U mL−1), protein (6.88 ± 0.37 mg mL−1), immunoglobulin (IgM; 5.34 ± 0.37 unit-mg mL−1), and protease activity (3.18 ± 0.36%) were significantly higher in BG40 than in the control; whereas, there was no significant effect on the alkaline phosphatase level. Among serum immune activity, activities of lysozyme, the alternative complement pathway, and IgM were significantly higher in BG40. Phagocytic, and superoxide dismutase (SOD) activities were higher (P < 0.05) in BG30–BG50. Serum ALT, AST, and MDA levels were lower in BG40 than in the control (P < 0.05). Intestinal enzymatic activities were enhanced in BG40 and BG50 (P < 0.05), except for lipase in BG50. Gene expression analysis revealed that the mRNA expressions of antioxidant genes (SOD , GPx , and Nrf2), an anti-inflammatory gene (IL-10), and IκBα were significantly upregulated in BG40. Conversely, the pro-inflammatory gene IL-1β and the signaling molecule NF-κB p65 were downregulated in BG40 and BG50, respectively. BG supplementation had no significant effect on TNF-α , TLR22 , or HSP7 0 mRNA expressions. Moreover, fish in BG40 exhibited the highest relative post-challenge survival (67.74%) against Aeromonas hydrophila infection. These results suggested that dietary supplementation with BG leaves at 40 g/kg can significantly improve the growth performance, immune responses, and disease resistance of C. carpio. BG leaves are a promising food additive for carp in aquaculture. • Dietary Bougainvillea glabra leaf improves the growth performance in Cyprinus carpio. • B. glabra supplementation increased the growth, anti-oxidant status, and immune responses of fish. • B. glabra at 40 g/Kg provided significant protection against Aeromonas hydrophila challenge. • Dietary supplementation with 40 g/kg B. glabra leaves showed significant benefits. [ABSTRACT FROM AUTHOR]

The genes of α-expansins of woody plants are of great interest for genetic engineering, since they can potentially be used to improve the tree growth parameters. In the flora of Russia, model woody plants for plant biotechnology are aspen ( Populus tremula L.) and black poplar ( Populus nigra L.). The objective of this study was to determine the role of α-expansin-encoding genes, aspen PtrEXPA3 and black poplar PnEXPA3, in the regulation and maintenance of woody plant growth. To achieve this goal, the PtrEXPA3 expression level were determined upon exogenous phytohormone treatment, the action of stress factors, and constitutive expression of the PnARGOS-LIKE gene. In addition, transgenic aspen plants with constitutive expression of the black poplar PnEXPA3 gene were generated, and their morphological analysis was carried out. The highest PtrEXPA3 mRNA level was detected in young intensely growing aspen leaves, and furthermore, expression of the gene was induced by exogenous cytokinins and auxins. In response to NaCl and constitutive expression of the PnARGOS-LIKE gene, the PtrEXPA3 mRNA level decreased. Transgenic aspen plants with constitutive PnEXPA3 expression were characterized by the decreased size of leaves, petioles, and internodes, as well as the increased size of leaf epidermal cells, while the stem size remained unchanged. Taken together, the data obtained enable the suggestion that the PtrEXPA3 and PnEXPA3 genes encode cytokinin- and auxin-regulated, leaf-specific expansins that are involved in the cell expansion. [ABSTRACT FROM AUTHOR]

Background: European Flint maize inbred lines are used as a source of adaptation to cold in most breeding programs in Northern Europe. A deep understanding of their adaptation strategy could thus provide valuable clues for further improvement, which is required in the current context of climate change. We therefore compared six inbreds and two derived Flint x Dent hybrids for their response to one-week at low temperature (10 °C day/7 or 4 °C night) during steady-state vegetative growth. Results: Leaf growth was arrested during chilling treatment but recovered fast upon return to warm temperature, so that no negative effect on shoot biomass was measured. Gene expression analyses of the emerging leaf in the hybrids suggest that plants maintained a 'ready-to-grow' state during chilling since cell cycle genes were not differentially expressed in the division zone and genes coding for expansins were on the opposite up-regulated in the elongation zone. In photosynthetic tissues, a strong reduction in PSII efficiency was measured. Chilling repressed chlorophyll biosynthesis; we detected accumulation of the precursor geranylgeranyl chlorophyll a and down-regulation of GERANYLGERANYL REDUCTASE (GGR) in mature leaf tissues. Excess light energy was mostly dissipated through fluorescence and constitutive thermal dissipation processes, rather than by light-regulated thermal dissipation. Consistently, only weak clues of xanthophyll cycle activation were found. CO2 assimilation was reduced by chilling, as well as the expression levels of genes encoding phosphoenolpyruvate carboxylase (PEPC), pyruvate orthophosphate dikinase (PPDK), and the small subunit of Rubisco. Accumulation of sugars was correlated with a strong decrease of the specific leaf area (SLA). Conclusions: Altogether, our study reveals good tolerance of the photosynthetic machinery of Northern European maize to chilling and suggests that growth arrest might be their strategy for fast recovery after a mild stress. [ABSTRACT FROM AUTHOR]

• 'Orri' mandarin has a low parthenocarpic ability, in accordance with its low CcGA3ox1 gene expression, but the application of GA 3 does not increase fruit set. • Ringing branches performed 35-40 days after anthesis increases fruitlet growth rate. This effect correlates inversely with the fruitlet abscission rate, and positively with cell division, i.e., with the CcCYCA1.1 gene expression in the fruitlet, but not with the GA biosynthesis, i. e., with the CcGA3ox1 gene expression. • Ringing branches significantly increased CcPIN1 gene expression in the fruitlet. • Results suggest that ringing protects the fruitlet abscission zone mediated by polar auxin transport from the fruit, which allows the fruitlet to maintain carbohydrate assimilation and continue growing. Ringing branches is a technique which is widely used to increase the yield of Citrus cultivars with low parthenocarpic ability. When performed during the physiological fruitlet abscission stage it prevents fruitlet drop and increases the number of fruits harvested. This effect has been related with an increased carbohydrate supply, which requires an enhanced photosynthesis efficiency of leafy flowering shoots. Since ringing also reduces vegetative growth, both the number of shoots and the leaves per shoot, the mechanism by which the carbohydrate supply is increased should be revised. Our results show that ringing carried out at this stage maintains the ability of the ovary for cell division mediated by the availability of carbohydrates, as indicated by an increased CcCYCA1.1 expression. But this effect is not linked with an increase in GA 1 biosynthesis (CcGA3ox1 expression), as this occurs during fruit set; hence, hormones other than gibberellin must be controlling the physiological fruitlet abscission in response to ringing. We found that an increased expression of the auxin efflux carrier CcPIN1 gene suggests that ringing induces the auxin export out of the fruitlet and transport to the abscission zone (AZ-C), thus inhibiting its activation and allowing carbohydrates supply to the fruitlet which, thus, prevents abscission and continues growth. [Display omitted] [ABSTRACT FROM AUTHOR]

Revealing the dynamic accumulation and synthesizing mechanism of medicinal bioactive products is critical for the evaluation and utilization of crops in medicinal industry. Huangqin (Scutellaria baicalensis Georgi) and Nianmao-Huangqin (Scutellaria viscidula Bge) are important medicinal crops containing flavonoids with good bioactivities. Previous studies have found significant differences of flavonoid contents between the two species. Nevertheless, the dynamic changes of bioactive products and related differential synthesizing mechanism remains unknown. In this study, an inter-specific comparative study was reported on the dynamic accumulation of eight bioactive products (scutellarin, scutellarein, baicalin, wogonoside, apigenin, baicalein, wogonin, and chrysin) and the expression of seven key enzyme genes in different organs (root, stem, and leaf) during different growth stages (May, June, July, August, September, and October) of S. baicalensis and S. viscidula. The results showed that the eight bioactive products were differentially accumulated in different growth stages for the two species. Specifically, the contents of five ingredients (except wogonoside, scutellarein and apigenin) in roots of S. baicalensis were significantly higher than those in S. viscidula in harvest stage (October). Meanwhile, the relative expression of seven key enzyme genes in baicalin synthesizing pathway showed significant spatio-temporal specificities. The expression of UBGAT in downstream baicalin synthesis was significantly higher in roots of S. baicalensis than that of S. viscidula (P < 0.05). Moreover, there exist significant correlations between the content of bioactive products and the expression of key enzyme genes. The expression of upstream (CLL-7 , FNSII-1 , FNSII-2) and downstream (F6H and UBGAT) key enzyme genes were significantly positively correlated with the contents of baicalin in both S. baicalensis and S. viscidula. On the contrary, the expression of GUS was significantly negatively correlated with the content of baicalin in the two species. Collectively, these results give clear evidences that the expression of key enzyme genes (e.g., FNSII-2 , GUS , and UBGAT) in baicalin synthesis is probably the main reason for the difference of bioactive products, suggesting that S. viscidula can be used as an alternative to S. baicalensis in pharmaceutical industry. Furthermore, these findings will provide a theoretical basis for exploring the inter-specific differences of bioactive products in medicinal crops within the same genus, thereby revealing the molecular mechanism of quality formation of Chinese medicinal materials. • Eight bioactive products showed content difference between two Scutellaria crops. • Seven key genes were differentially expressed in S. baicalensis and S. viscidula. • Difference of product content was correlated with difference of gene expression. • S. viscidula can be used as alternative medicinal source to S. baicalensis. • Molecular mechanism of differential bioactive product contents was revealed. [ABSTRACT FROM AUTHOR]

How gene activities and biomechanics together direct organ shapes is poorly understood. Plant leaf and floral organs develop from highly similar initial structures and share similar gene expression patterns, yet they gain drastically different shapes later—flat and bilateral leaf primordia and radially symmetric floral primordia, respectively. We analyzed cellular growth patterns and gene expression in young leaves and flowers of Arabidopsis thaliana and found significant differences in cell growth rates, which correlate with convergence sites of phytohormone auxin that require polar auxin transport. In leaf primordia, the PRESSED - FLOWER -expressing middle domain grows faster than adjacent adaxial domain and coincides with auxin convergence. In contrast, in floral primordia, the LEAFY -expressing domain shows accelerated growth rates and pronounced auxin convergence. This distinct cell growth dynamics between leaf and flower requires changes in levels of cell-wall pectin de-methyl-esterification and mechanical properties of the cell wall. Data-driven computer model simulations at organ and cellular levels demonstrate that growth differences are central to obtaining distinct organ shape, corroborating in planta observations. Together, our study provides a mechanistic basis for the establishment of early aerial organ symmetries through local modulation of differential growth patterns with auxin and biomechanics. [Display omitted] • Leaf and floral primordia share similar gene expression and initial domain partition • Local growth-rate differences across domains explain primordia shape differences • Two primordia have different patterns of cell-wall rigidity and auxin convergence • When incorporating growth dynamics, models explain different organ shapes Peng et al. show that different growth dynamics determine the shape of plant aerial organs, leaf and floral primordia, which share similar initial geometry. Experiments and simulations are combined to link growth dynamics with biomechanics and polar auxin transport. [ABSTRACT FROM AUTHOR]

Roots play an important role in the growth and development of plants and auxin participates in regulating plant root development. Some studies have shown that BS (BSISTER) gene (the closest gene of class B gene) is involved in plant root development, but whether BS regulates root development via auxin signaling still not clear. To explore VviBS1 and VviBS2 roles in root development, VviBS1 and VviBS2 were overexpressedin Arabidopsis tt16 mutant and we found that they could restore the phenotype of shorter PR (primary roots) and high density of LR (lateral root) of tt16 compared with the wild type Ws Arabidopsis seedlings. However, the addition of exogenous NAA (naphthalene acetic acid) could not significantly promote the PR length of tt16 Arabidopsis, and the auxin signal transduction of tt16 may be blocked. The expression levels of auxin signal transduction pathway genes in Ws, tt16 , p35s:VviBS1 in tt16 and p35s:VviBS2 in tt16 seedlings were detected. It was found that the expression of AtARF2 , AtARF12 , AtARF14 , AtARF15 , AtARF20 , AtGH3 , AtGH3 -2 and AtSAUR51 genes in tt16 seedlings was higher than that in Ws, while the expression of AtIAA19 and AtIAA29 in Ws seedlings was higher than that of tt16. More importantly, BS may up regulate AtIAA19 and AtIAA29 expression directly by binding to their promoter. In addition, VviBS1 and VviBS2 also affect seed germination and may regulate leaf yellowing by regulating ethylene synthase. Therefore, our findings reveal a molecular mechanism that BS may modulate root system development via Aux/IAA-based auxin signaling, and provide insight into the BS function in regulation of leaf yellowing. • Overexpression of VviBS1 and VviBS2 could restore the phenotype of shorter PR and high density of LR in Arabidopsis tt16. • BS regulates root development by binding to the promoter region of AtIAA19 and AtIAA29 which involved in auxin signaling. • VviBS1 and VviBS2 affect seed germination and may regulate leaf yellowing by regulating ethylene synthase. [ABSTRACT FROM AUTHOR]

The NGATHA ( NGA) clade of transcription factors (TFs) forms a small subfamily of four members in Arabidopsis thaliana. NGA genes act redundantly to direct the development of apical tissues in the gynoecium, where they have been shown to be essential for style and stigma specification. In addition, NGA genes have a more general role in controlling lateral organ growth. The four NGA genes in Arabidopsis are expressed in very similar domains, although little is known about the nature of their putative regulators. Here, we have identified a conserved region within the four NGA promoters that we have used as a bait to screen a yeast library, aiming to identify such NGA regulators. Three members of the TCP family of TFs, named after the founding factors TEOSINTE BRANCHED 1, CYCLOIDEA and PROLIFERATING CELL FACTOR 1 AND 2), were recovered from this screening, of which two [ TCP2 and TCP3, members of the CINCINNATA (CIN) family of TCP genes (CIN-TCP) subclade] were shown to activate the NGA3 promoter in planta. We provide evidence that support that CIN-TCP genes are true regulators of NGA gene expression, and that part of the CIN-TCP role in leaf development is mediated by NGA upregulation. Moreover, we have found that this TCP-NGA regulatory interaction is likely conserved in angiosperms, including important crop species, for which the regulation of leaf development is a target for biotechnological improvement. [ABSTRACT FROM AUTHOR]

Phenotypic plasticity is considered as an important mechanism for plants to cope with environmental challenges. Leaf growth is one of the first macroscopic processes to be impacted by modification of soil water availability. In this study, we intended to analyze and compare plasticity at different scales. We examined the differential effect of water regime (optimal, moderate water deprivation and recovery) on growth and on the expression of candidate genes in leaves of different growth stages. Candidates were selected to assess components of growth response: abscisic acid signaling, water transport, cell wall modification and stomatal development signaling network. At the tree scale, the four studied poplar hybrids responded similarly to water regime. Meanwhile, leaf growth response was under genotype × environment interaction. Patterns of candidate gene expression enriched our knowledge about their functionality in poplars. For most candidates, transcript levels were strongly structured according to leaf growth performance while response to water regime was clearly dependent on genotype. The use of an index of plasticity revealed that the magnitude of the response was higher for gene expression than for macroscopic traits. In addition, the ranking of poplar genotypes for macroscopic traits well paralleled the one for gene expression. [ABSTRACT FROM AUTHOR]

Climate change, currently taking place worldwide and also in the Mediterranean area, is leading to a reduction in water availability and to groundwater salinization. Olive represents one of the most efficient tree crops to face these scenarios, thanks to its natural ability to tolerate moderate salinity and drought. In the present work, four olive cultivars (Koroneiki, Picual, Royal de Cazorla and Fadak86) were exposed to high salt stress conditions (200 mM of NaCl) in greenhouse, in order to evaluate their tolerance level and to identify key genes involved in salt stress response. Molecular and physiological parameters, as well as plant growth and leaves' ions Na+ and K+ content were measured. Results of the physiological measurements showed Royal de Cazorla as the most tolerant cultivar, and Fadak86 and Picual as the most susceptible ones. Ten candidate genes were analyzed and their complete genomic, CDS and protein sequences were identified. The expression analysis of their transcripts through reverse transcriptase quantitative PCR (RT-qPCR) demonstrated that only OeNHX7, OeP5CS, OeRD19A and OePetD were upregulated in tolerant cultivars, thus suggesting their key role in the activation of a salt tolerance mechanism. [ABSTRACT FROM AUTHOR]

Background: Salinity inhibits growth and development of most plants. The response to salinity is complex and varies between plant organs and stages of development. It involves challenges of ion toxicities and deficiencies as well as osmotic and oxidative stresses. The range of functions affected by the stress is reflected in elaborate changes to the transcriptome. The mechanisms involved in the developmental-stage specificity of the inhibitory responses are not fully understood. The present study took advantage of the well characterized developmental progression that exists along the maize leaf, for identification of salinity induced, developmentally-associated changes to the transcriptome. Differential subtraction screening was conducted for cells of two developmental stages: from the center of the growth zone where the expansion rate is highest, and from older cells at a more distal location of the growing zone where the expansion rate is lower and the salinity restrictive effects are more pronounced. Real-Time PCR analysis was used for validation of the expression of selected genes. Results: The salinity-induced changes demonstrated an age-related response of the growing tissue, with elevation of salinity-damages with increased age. Growth reduction, similar to the elevation of percentage dry matter (%DM), and Na and Cl concentrations were more pronounced in the older cells. The differential subtraction screening identified genes encoding to proteins involved in antioxidant defense, electron transfer and energy, structural proteins, transcription factors and photosynthesis proteins. Of special interest is the higher induced expression of genes involved in antioxidant protection in the young compared to older cells, which was accompanied by suppressed levels of reactive oxygen species (H2O2 and O2 - ). This was coupled with heightened expression in the older cells of genes that enhance cell-wall rigidity, which points at reduced potential for cell expansion. Conclusions: The results demonstrate a cell-age specificity in the salinity response of growing cells, and point at involvement of the antioxidative response in cell growth restriction. Processes involved in reactive oxygen species (ROS) scavenging are more pronounced in the young cells, while the higher growth sensitivity of older cells is suggested to involve effects on cell-wall rigidity and lower protein protection. [ABSTRACT FROM AUTHOR]

Expansins are cell wall proteins implicated in the control of plant growth via loosening of the extracellular matrix. They are encoded by a large gene family, and data linked to loss of single gene function to support a role of expansins in leaf growth remain limited. Here, we provide a quantitative growth analysis of transgenics containing an inducible artificial microRNA construct designed to down-regulate the expression of a number of expansin genes that an expression analysis indicated are expressed during the development of Arabidopsis (Arabidopsis thaliana) leaf 6. The results support the hypothesis that expansins are required for leaf growth and show that decreased expansin gene expression leads to a more marked repression of growth during the later stage of leaf development. In addition, a histological analysis of leaves in which expansin gene expression was suppressed indicates that, despite smaller leaves, mean cell size was increased. These data provide functional evidence for a role of expansins in leaf growth, indicate the importance of tissue/organ developmental context for the outcome of altered expansin gene expression, and highlight the separation of the outcome of expansin gene expression at the cellular and organ levels. [ABSTRACT FROM AUTHOR]