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SUMMARY: HSP90Cs are essential molecular chaperones localized in the plastid stroma that maintain protein homeostasis and assist the import and thylakoid transport of chloroplast proteins. While HSP90C contains all conserved domains as an HSP90 family protein, it also possesses a unique feature in its variable C‐terminal extension (CTE) region. This study elucidated the specific function of this HSP90C CTE region. Our phylogenetic analyses revealed that this intrinsically disordered region contains a highly conserved DPW motif in the green lineages. With biochemical assays, we showed that the CTE is required for the chaperone to effectively interact with client proteins PsbO1 and LHCB2 to regulate ATP‐independent chaperone activity and to effectuate its ATP hydrolysis. The CTE truncation mutants could support plant growth and development reminiscing the wild type under normal conditions except for a minor phenotype in cotyledon when expressed at a level comparable to wild type. However, higher HSP90C expression was observed to correlate with a stronger response to specific photosystem II inhibitor DCMU, and CTE truncations dampened the response. Additionally, when treated with lincomycin to inhibit chloroplast protein translation, CTE truncation mutants showed a delayed response to PsbO1 expression repression, suggesting its role in chloroplast retrograde signaling. Our study therefore provides insights into the mechanism of HSP90C in client protein binding and the regulation of green chloroplast maturation and function, especially under stress conditions. [ABSTRACT FROM AUTHOR]

The endoplasmic reticulum (ER) is the largest organelle in terms of membrane content, occupying the entire cytoplasmic volume. It is tethered to the cell cortex through ER‐plasma membrane contact sites (EPCS). Previous studies have shown that EPCSs labelled by VAP27 align with cortical microtubules, and that ER tubules elongate along microtubules. Here, we addressed the question whether this relationship is bidirectional, with EPCSs influencing microtubule organisation. Using TIRF microscopy to track EPCSs and microtubule dynamics simultaneously, we demonstrate that while EPCSs remain stable, microtubules are highly dynamic and can adjust their positioning based on nearby EPCS in Arabidopsis cotyledon epidermis. In lobes of epidermal cells enclosed by two indentations, where microtubules bundle together, EPCSs flank the bundles and exhibit a distinctive arrangement, forming symmetric arcs in relation to the lobe axis. In guard cells, transversely oriented ER tubules co‐align with microtubules. Disrupting microtubules with the drug oryzalin leads to transient guard cells‐ER remodelling, followed by its reorganisation into transverse tubules before microtubule recovery. Taken together our observations suggest, that the positioning of EPCSs and cortical microtubules, can affect each other and the organisation of cortical ER. [ABSTRACT FROM AUTHOR]

Background: Plant long non-coding RNAs (lncRNAs) have important regulatory roles in responses to various biotic and abiotic stresses, including light quality. However, no lncRNAs have been specifically linked to the Shade Avoidance Response (SAS). Results: To better understand the involvement of lncRNAs in shade avoidance, we examined RNA-seq libraries for lncRNAs with the potential to function in the neighbor proximity phenomenon in Arabidopsis thaliana (A. thaliana). Using transcriptomes generated from seedlings exposed to high and low red/far-red (R/FR) light conditions, we identified 13 lncRNA genes differentially expressed in cotyledons and 138 in hypocotyls. To infer possible functions for these lncRNAs, we used a 'guilt-by-association' approach to identify genes co-expressed with lncRNAs in a weighted gene co-expression network. Of 34 co-expression modules, 10 showed biological functions related to differential growth. We identified three potential lncRNAs co-regulated with genes related to SAS. T-DNA insertions in two of these lncRNAs were correlated with morphological differences in seedling responses to increased FR light, supporting our strategy for computational identification of lncRNAs involved in SAS. Conclusions: Using a computational approach, we identified multiple lncRNAs in Arabidopsis involved in SAS. T-DNA insertions caused altered phenotypes under low R/FR light, suggesting functional roles in shade avoidance. Further experiments are needed to determine the specific mechanisms of these lncRNAs in SAS. [ABSTRACT FROM AUTHOR]

Summary: The homology of the single cotyledon of grasses and the ontogeny of the scutellum and coleoptile as the initial, highly modified structures of the grass embryo are investigated using leaf developmental genetics and targeted transcript analyses in the model grass Zea mays subsp. mays.Transcripts of leaf developmental genes are identified in both the initiating scutellum and the coleoptile, while mutations disrupting mediolateral leaf development also disrupt scutellum and coleoptile morphology, suggesting that these grass‐specific organs are modified leaves.Higher‐order mutations in WUSCHEL‐LIKE HOMEOBOX3 (WOX3) genes, involved in mediolateral patterning of plant lateral organs, inform a model for the fusion of coleoptilar margins during maize embryo development.Genetic, RNA‐targeting, and morphological evidence supports models for cotyledon evolution where the scutellum and coleoptile, respectively, comprise the distal and proximal domains of the highly modified, single grass cotyledon. [ABSTRACT FROM AUTHOR]

ABSTRACT It has been proposed that cortical fine actin filaments are needed for the morphogenesis of pavement cells (PCs). However, the precise role and regulation mechanisms of actin filaments in PC morphogenesis are not well understood. Here, we found that Arabidopsis thaliana ACTIN DEPOLYMERIZING FACTOR9 (ADF9) is required for the morphogenesis of PC, which is negatively regulated by the R2R3 MYELOBLASTOSIS (MYB) transcription factor MYB52. In adf9 mutants, the lobe number of cotyledon PCs was significantly reduced, while the average lobe length did not differ significantly compared to that of wild type (Col‐0), except for the variations in cell area and circularity, whereas the PC shapes in ADF9 overexpression seedlings showed different results. ADF9 decorated actin filaments, and colocalized with plasma membrane. The extent of filament bundling and actin filament bundling activity in adf9 mutant decreased. In addition, MYB52 directly targeted the promoter of ADF9 and negatively regulated its expression. The myb52‐2 mutant showed increased lobe number and cell area, reduced cell circularity of PCs, and the PC phenotypes were suppressed when ADF9 was knocked out. Taken together, our data demonstrate that actin filaments play an important role in the morphogenesis of PC and reveal a transcriptional mechanism underlying MYB52 regulation of ADF9‐mediated actin filament bundling in PC morphogenesis. [ABSTRACT FROM AUTHOR]

The current study investigated the impact of germination duration on the functional components (vitamin C, γ-aminobutyric acid (GABA), polyphenols, flavonoids) and antioxidant activity of germs and cotyledons of the germinated Chinese chestnut (Castanea mollissima). We utilized seeds of the "Zaofeng" Chinese chestnut to germinate, and sowed the seeds in wet sand at 22 °C and 85% relative humidity. The germination rate, length, diameter, and fresh weight of the sprouts were investigated at 0, 2, 4, 6, 8, and 10 days after sowing, and the kinetic changes of amylose, amylopectin, sugar components, soluble protein, vitamin C, GABA, total phenols, flavonoids, and the DPPH and ABTS free radical scavenging activity in the germs and cotyledons were monitored, respectively. The findings revealed that the germination rate and germ biomass increased continuously during germination. The germination rate reached 90% on the 8th day after sowing. Germination reduced amylose in cotyledons from 42.3% to 34.2%, amylopectin from 42.9% to 25.8%, total sugar from 12.6% to 11.4%, and vitamin C from 1.45 mg/g to 0.77 mg/g. Meanwhile, soluble protein in the embryos rose from 0.31% to 0.60%, vitamin C from 21.1 to 29.4 mg/g, GABA from 0.49 to 1.68 mg/g, total flavonoids from 53.6 to 129.7 mg/g, and ABTS antioxidant activity from 1.52 to 3.27 μmol TE/g. The average contents of D-fructose, inositol, vitamin C, GABA, polyphenols, and flavonoids and the DPPH and ABTS antioxidant activity in germs were as high as 22.5, 6, 35, 7.5, 10, 20, and 10 and 20-fold those of cotyledons, respectively. Especially, the average content of glucose in germ was as high as 80-fold that of cotyledon. D-xylulose, D-galacturonic acid, and D-ribose were only found in germs, but not in cotyledons. Considering the germ biomass and functional components content, germs of Chinese chestnuts germinated at 22 °C for 8 days are considered the most suitable raw material for functional food products. In conclusion, controlled germination not only enhances the physicochemical and functional properties of Chinese chestnut germs but also reduces the caloric content and improves the nutritional composition of the cotyledons appropriately. Moreover, the comprehensive evaluation of compositional changes and functionality in the embryo and cotyledon of Chinese chestnuts will provide a solid foundation for subsequent functional food processing utilizing germinated Chinese chestnuts. [ABSTRACT FROM AUTHOR]

Light is crucial for plants and serves as a signal for modulating their growth. Under shade, where red to far-red light ratio is low, plants exhibit shade avoidance responses (SAR). LONG HYPOCOTYL IN FAR-RED 1 (HFR1) and ELONGATED HYPOCOTYL 5 (HY5) are known to be negative regulators of SAR and physically interact with one another. However, transcriptional regulatory network underlying SAR by these two transcription factors has not been explored. Here, we performed organ-specific transcriptome analyses of Arabidopsis thaliana hfr1-5, hy5-215 and hfr1hy5 to identify genes that are co-regulated by HFR1 and HY5 in hypocotyls and cotyledons. Genes co-regulated by HFR1 and HY5 were enriched in various processes related to cell wall modification and chlorophyll biosynthesis in hypocotyls. Phytohormone (abscisic acid and jasmonic acid) and light responses were significantly regulated by HFR1 and HY5 in both organs, though it is more prominent under shade in cotyledons. HFR1 and HY5 also differentially regulate the expression of the cell wall-related genes for xyloglucan endotransglucosylase/hydrolase, expansin, arabinogalactan protein and class III peroxidase depending on the organs. Furthermore, HFR1 and HY5 cooperatively regulated hypocotyl responsiveness to shade through auxin metabolism. Together, our study illustrates the importance of the HFR1-HY5 module in regulating organ-specific shade responses in Arabidopsis. [ABSTRACT FROM AUTHOR]

Cold stress affects the seed germination and early growth of winter rapeseed, leading to yield losses. We employed transmission electron microscopy, physiological analyses, metabolome profiling, and transcriptome sequencing to understand the effect of cold stress (0 °C, LW) on the cotyledons of cold-tolerant (GX74) and -sensitive (XY15) rapeseeds. The mesophyll cells in cold-treated XY15 were severely damaged compared to slightly damaged cells in GX74. The fructose, glucose, malondialdehyde, and proline contents increased after cold stress in both genotypes; however, GX74 had significantly higher content than XY15. The pyruvic acid content increased after cold stress in GX74, but decreased in XY15. Metabolome analysis detected 590 compounds, of which 32 and 74 were differentially accumulated in GX74 (CK vs. cold stress) and XY15 (CK vs. cold stressed). Arachidonic acid and magnoflorine were the most up-accumulated metabolites in GX74 subjected to cold stress compared to CK. There were 461 and 1481 differentially expressed genes (DEGs) specific to XY15 and GX74 rapeseeds, respectively. Generally, the commonly expressed genes had higher expressions in GX74 compared to XY15 in CK and cold stress conditions. The expression changes in DEGs related to photosynthesis-antenna proteins, chlorophyll biosynthesis, and sugar biosynthesis-related pathways were consistent with the fructose and glucose levels in cotyledons. Compared to XY15, GX74 showed upregulation of a higher number of genes/transcripts related to arachidonic acid, pyruvic acid, arginine and proline biosynthesis, cell wall changes, reactive oxygen species scavenging, cold-responsive pathways, and phytohormone-related pathways. Taken together, our results provide a detailed overview of the cold stress responses in rapeseed cotyledons. [ABSTRACT FROM AUTHOR]

The article examines the GoPGS gene's role in regulating pigment gland size in cotton plants and its connection to biotic stress tolerance. Researchers discovered that suppressing the GoPGS gene resulted in larger pigment glands and increased resistance to pests and pathogens. They also found that the GoPGS gene is controlled by the GoPGF gene and is involved in the jasmonic acid pathway. These findings offer insights into the development of cotton pigment glands and their role in defending against biotic stress. Manipulating the GoPGS gene's activity may be a potential method for enhancing cotton plants' resistance to biotic stresses. [Extracted from the article]

Day length modulates hypocotyl elongation in seedlings to optimize their overall fitness. Variations in cell growth‐associated genes are regulated by several transcription factors. However, the specific transcription factors through which the plant clock increases plant fitness are still being elucidated. In this study, we identified the no apical meristem, Arabidopsis thaliana‐activating factor (ATAF‐1/2), and cup‐shaped cotyledon (NAC) family transcription factor ATAF1 as a novel repressor of hypocotyl elongation under a short‐day (SD) photoperiod. Variations in day length profoundly affected the transcriptional and protein levels of ATAF1. ATAF1‐deficient mutant exhibited increased hypocotyl length and cell growth‐promoting gene expression under SD conditions. Moreover, ATAF1 directly targeted and repressed the expression of the cycling Dof factor 1/5 (CDF1/5), two key transcription factors involved in hypocotyl elongation under SD conditions. Additionally, ATAF1 interacted with and negatively modulated the effects of phytochrome‐interacting factor (PIF), thus inhibiting PIF‐promoted gene expression and hypocotyl elongation. Taken together, our results revealed ATAF1–PIF as a crucial pair modulating the expression of key transcription factors to facilitate plant growth during day/night cycles under fluctuating light conditions. Summary statement: This study identified Arabidopsis NAC transcription factor Arabidopsis thaliana‐activating factor (ATAF1) as a novel repressor of hypocotyl elongation under short‐day conditions. ATAF1 controls the transcription levels of key regulator CDF1/5 by repressing the central regulators phytochrome‐interacting factor via protein–protein interaction. [ABSTRACT FROM AUTHOR]

A stoma forms by a series of asymmetric divisions of stomatal lineage precursor cell and the terminal division of a guard mother cell (GMC). GMC division is restricted to once through genetic regulation mechanisms. Here, we show that nitric oxide (NO) is involved in the regulation of the GMC division. NO donor treatment results in the formation of single guard cells (SGCs). SGCs are also produced in plants that accumulate high NO, whereas clustered guard cells (GCs) appear in plants with low NO accumulation. NO treatment promotes the formation of SGCs in the stomatal signalling mutants sdd1, epf1 epf2, tmm1, erl1 erl2 and er erl1 erl2, reduces the cell number per stomatal cluster in the fama‐1 and flp1 myb88, but has no effect on stomatal of cdkb1;1 cyca2;234. Aminocyclopropane‐1‐carboxylic acid (ACC), a positive regulator of GMC division, reduces the NO‐induced SGC formation. Further investigation found NO inhibits ACC synthesis by repressing the expression of several ACC SYNTHASE (ACS) genes, and in turn ACC represses NO accumulation by promoting the expression of HEMOGLOBIN 1 (HB1) encoding a NO scavenger. This work shows NO plays a role in the regulation of GMC division by modulating ACC accumulation in the Arabidopsis cotyledon. Summary statement: Nitric oxide is able to repress the terminal division of guard mother cell (GMC) by reducing the accumulation of aminocyclopropane‐1‐carboxylic acid which is a positive regulator of GMC division. [ABSTRACT FROM AUTHOR]

Black soybeans with green cotyledon have long been widely consumed in the East due to their high content of health-promoting anthocyanins and lutein. However, major anti-nutritional and allergenic components such as lectin, Kunitz trypsin inhibitor (KTI), P34, lipoxygenase, and stachyose are contained in mature seed. The objective of this research is to breed a soybean line with a black seed coat, a green cotyledon, and the penta null genotype (lele-titi-p34p34-lox1lox1lox2lox2lox3lox3-rs2rs2) for all five components. The F2 plant strain with penta null genotype for lectin, KTI, P34, lipoxygenase, and stachyose components was developed. The breeding line has purple flower, determinate growth habit, brown pod, black seed coat and green cotyledon. The stem height of the breeding line was 57.0 cm and 100 seed weight was 31.5 g. This is the first soybean breeding line with black seed coat, green cotyledon and penta null genotypes for lectin, KTI, P34, lipoxygenase, and stachyose factors. This line will be used as parent to improve a black soybean cultivar with green cotyledon that have significantly reduced anti-nutritional and allergenic traits. [ABSTRACT FROM AUTHOR]

Wild rocket downy mildew (DM), caused by oomycete Hyaloperonospora sp., is a widely spread disease reducing crop production and quality. New productive wild rocket varieties resistant to DM are crucial to control disease and ensure high quality leaves. A histological characterization of Hyaloperonospora sp. infection was performed in 11 wild rocket (Diplotaxis tenuifolia) accessions with contrasting DM responses (R, resistant; PR, partially resistant; S, susceptible). Samples of infected cotyledons, first and second leaves of 14‐day‐old seedlings were collected at 3, 6, 9, 21 and 24 h post‐inoculation (hpi) and 7 days post‐inoculation (dpi) and stained for appressoria and haustoria observation and tissue necrosis evaluation. Occurrence of appressoria on host surfaces was higher in leaves compared with cotyledons but unrelated with DM resistance response. Haustoria growth in mycelium was delayed in R accessions from 3 hpi, and signs of cell hypersensitivity reaction were observed at 9 hpi. At 24 hpi, necrotic spots limited pathogen growth in resistant accessions, whilst mycelium invaded larger mesophyll areas and produced more haustoria in susceptible ones. At 7 dpi, sporulation was heavy in S, restricted to droplet deposition sites in PR, and did not occur in R hosts. A rapid response of R accessions resulted in slower mycelium growth and longer infection periods. These traits have important agronomic value and should be considered in germplasm selection for breeding programmes aimed at crop protection. A better understanding of the host response to DM infection will allow selection of more suitable wild rocket accessions in future breeding programmes. [ABSTRACT FROM AUTHOR]

The article presents the biological features of Arctium tomentosum Mill. in natural and sowing conditions, the changes in morpho-anatomical structure of vegetative organs in ontogenesis. The growth rate of the germinal root was quite active, and the formation of many lateral roots was observed at the juvenile stage of life. There was an increase of the neck of the germinal root in the immature state, the formation of primary and secondary lateral roots in length, and an increase in the level of growth of the germinal root in the virginal age state. In the generative state, in the second year of life, the lateral roots form two distinct layers. The seed shell in the natural environment is lamellar, without protein, the seed is well ripened. In the next juvenile state, it was observed that the components of the xylem and phloem were not fully formed in the leaf-like cotyledon, with an underdeveloped mesophyll, of a homogeneous type. The first anatomical features in the root structure have been clarified. The size and shape of mesophyll cells are stable, columnar and loose parenchyma are determined, conductive tissues are formed. The anatomical structure of the root undergoes a period of over-development. In the generative state, the size of the central cylinder increased in the structure of the root, the layer of cutin thickened on the leaves, and the layer of columnar mesophyll containing chlorophyll grains increased. There was an accumulation of idiotic cells and needle-like calcium oxalate druzes in the root. [ABSTRACT FROM AUTHOR]

Because of the lack of good seedling positioning during vegetable grafting, there are issues such as high labor costs and long grafting time. This article proposes a negative pressure suction seedling positioning method for seed leaves based on the characteristic parameters of cucumber spike wood, and designs a flexible adsorption positioning mechanism for spike wood. Firstly, the ventral surface curve trajectories of cucumber cotyledons were extracted using Matlab software, and then a shape-adaptive design was applied to the attachment surface of the flexible suction positioning mechanism, and a computational fluid dynamics model of the airflow field was established. By combining Fluent simulation analysis with orthogonal experiments, the effect of suction hole diameter, vacuum negative pressure value, suction hole quantity, and suction hole depth on the adsorption effect of the suction head was analyzed, the main and secondary factors and operational indicators that affect the adsorption effect are evaluated. The optimal parameter combination: suction hole diameter of 1.5 mm, vacuum negative pressure value of 2 kPa, suction hole quantity of 42, and suction hole depth of 2 mm, has been found. A verification experiment was conducted on a test bench, and the experimental results show that the success rate of leaf absorption using the optimal parameter combination is 97.69%, which indicates that the suction head is designed reasonably and meets the requirements of grafting. [ABSTRACT FROM AUTHOR]

Summary Branch length is an important plant architecture trait in cotton (Gossypium) breeding. Development of cultivars with short branch has been proposed as a main object to enhance cotton yield potential, because they are suitable for high planting density. Here, we report the molecular cloning and characterization of a semi‐dominant quantitative trait locus, Short Branch Internode 1(GhSBI1), which encodes a NAC transcription factor homologous to CUP‐SHAPED COTYLEDON 2 (CUC2) and is regulated by microRNA ghr‐miR164. We demonstrate that a point mutation found in sbi1 mutants perturbs ghr‐miR164‐directed regulation of GhSBI1, resulting in an increased expression level of GhSBI1. The sbi1 mutant was sensitive to exogenous gibberellic acid (GA) treatments. Overexpression of GhSBI1 inhibited branch internode elongation and led to the decreased levels of bioactive GAs. In addition, gene knockout analysis showed that GhSBI1 is required for the maintenance of the boundaries of multiple tissues in cotton. Transcriptome analysis revealed that overexpression of GhSBI1 affects the expression of plant hormone signalling‐, axillary meristems initiation‐, and abiotic stress response‐related genes. GhSBI1 interacted with GAIs, the DELLA repressors of GA signalling. GhSBI1 represses expression of GA signalling‐ and cell elongation‐related genes by directly targeting their promoters. Our work thus provides new insights into the molecular mechanisms for branch length and paves the way for the development of elite cultivars with suitable plant architecture in cotton. [ABSTRACT FROM AUTHOR]

In our research, we utilized six small-fruited pepper germplasms as materials, selected cotyledons with the petiole and hypocotyls as explants, and conducted in vitro regeneration studies. Our outcomes specify that the most suitable explant is cotyledon with the petiole, and the suitable genotype is HNUCA341. The optimal medium for inducing and elongating adventitious buds for this genotype is Murashige and Skoog medium (MS) + 9.12 μM Zeatin (ZT) + 0.57 μM 3-Indoleacetic acid (IAA), with a bud induction rate of 44.4%. The best rooting induction medium is MS + 1.14 μM IAA, with a rooting rate of 86.7%. Research on the addition of exogenous hormones has revealed that the induction speed of buds in small-fruited pepper (HNUCA341) in the combination of ZT and IAA hormones (abbreviated as ZI) is quicker, and the induction effect is better. The histological observations indicate that ZI treatment accelerates the initiation of explant division and differentiation, causing a shorter duration of vascular-bundle tissue production. The plant hormone signaling pathway was significantly enriched by Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, including ARR9 (LOC107843874, LOC107843885), ARR4 (LOC107848380, LOC107862455), AHK4 (LOC107870540), AHP1 (LOC107839518), LAX2 (LOC107846008), SAUR36 (LOC107852624), IAA8 (LOC107841020), IAA16 (LOC107839415), PYL4 (LOC107843441), and PYL6 (LOC107871127); these significantly enriched genes may be associated with in vitro regeneration. In addition, the carbon metabolism pathway and plant mitogen-activated protein kinase (MAPK) signaling pathway are also significantly enriched in KEGG. The results of the Gene Ontology (GO) analysis revealed that differentially expressed genes related to carbon metabolism and fixation, photosynthesis and MAPK signaling pathways were upregulated under ZI treatment. It was found that they might be associated with enhanced regeneration in vitro. Furthermore, we also screened out differentially expressed transcription factors, primarily from the MYB, bHLH, AP2/ERF, and NAC families. Overall, our work accumulated important data for the in-depth analysis of the molecular mechanism of in vitro regeneration of pepper, and provides valuable germplasm for establishing an efficient stable pepper genetic-transformation system based on tissue culture. [ABSTRACT FROM AUTHOR]

Background: The co-occurrence of C4 and CAM photosynthesis in a single species seems to be unusual and rare. This is likely due to the difficulty in effectively co-regulating both pathways. Here, we conducted a comparative transcriptomic analysis of leaves and cotyledons of the C4-like species Sesuvium sesuvioides (Aizoaceae) using RNA-seq. Results: When compared to cotyledons, phosphoenolpyruvate carboxylase 4 (PEPC4) and some key C4 genes were found to be up-regulated in leaves. During the day, the expression of NADP-dependent malic enzyme (NADP-ME) was significantly higher in cotyledons than in leaves. The titratable acidity confirmed higher acidity in the morning than in the previous evening indicating the induction of weak CAM in cotyledons by environmental conditions. Comparison of the leaves of S. sesuvioides (C4-like) and S. portulacastrum (C3) revealed that PEPC1 was significantly higher in S. sesuvioides, while PEPC3 and PEPC4 were up-regulated in S. portulacastrum. Finally, potential key regulatory elements involved in the C4-like and CAM pathways were identified. Conclusions: These findings provide a new species in which C4-like and CAM co-occur and raise the question if this phenomenon is indeed so rare or just hard to detect and probably more common in succulent C4 lineages. [ABSTRACT FROM AUTHOR]

Seed water imbibition is critical to seedling establishment in tropical forests. The seeds of the neotropical tree Hymenaea courbaril have no oil reserves and have been used as a model to study storage cell wall polysaccharide (xyloglucan – XyG) mobilization. We studied pathways of water imbibition in Hymenaea seeds. To understand seed features, we performed carbohydrate analysis and scanning electron microscopy. We found that the seed coat comprises a palisade of lignified cells, below which are several cell layers with cell walls rich in pectin. The cotyledons are composed mainly of storage XyG. From a single point of scarification on the seed surface, we followed water imbibition pathways in the entire seed using fluorescent dye and NMRi spectroscopy. We constructed composites of cellulose with Hymenaea pectin or XyG. In vitro experiments demonstrated cell wall polymer capacity to imbibe water, with XyG imbibition much slower than the pectin‐rich layer of the seed coat. We found that water rapidly crosses the lignified layer and reaches the pectin‐rich palisade layer so that water rapidly surrounds the whole seed. Water travels very slowly in cotyledons (most of the seed mass) because it is imbibed in the XyG‐rich storage walls. However, there are channels among the cotyledon cells through which water travels rapidly, so the primary cell walls containing pectins will retain water around each storage cell. The different seed tissue dynamic interactions between water and wall polysaccharides (pectins and XyG) are essential to determining water distribution and preparing the seed for germination. [ABSTRACT FROM AUTHOR]

Introduction: Abscisic acid (ABA) can negatively regulate seed germination, but the mechanisms of ABA-mediated metabolism modulation are not well understood. Moreover, it remains unclear whether metabolic pathways vary with the different tissue parts of the embryo, such as the radicle, hypocotyl and cotyledon. Methods: In this report, we performed the first comprehensive metabolome analysis of the radicle and hypocotyl + cotyledon in Pinus koraiensis seeds in response to ABA treatment during germination. Results and discussion: Metabolome profiling showed that following ABA treatment, 67 significantly differentially accumulated metabolites in the embryo were closely associated with pyrimidine metabolism, phenylalanine metabolism, cysteine and methionine metabolism, galactose metabolism, terpenoid backbone biosynthesis, and glutathione metabolism. Meanwhile, 62 metabolites in the hypocotyl + cotyledon were primarily involved in glycerophospholipid metabolism and glycolysis/gluconeogenesis. We can conclude that ABA may inhibit Korean pine seed germination primarily by disrupting the biosynthesis of certain plant hormones mediated by cysteine and methionine metabolism and terpenoid backbone biosynthesis, as well as reducing the reactive oxygen species scavenging ability regulated by glutathione metabolism and shikimate pathway in radicle. ABA may strongly disrupt the structure and function of cellular membranes due to alterations in glycerophospholipid metabolism, and weaken glycolysis/gluconeogenesis in the hypocotyl + cotyledon, both of which are major contributors to ABAmediated inhibition of seed germination. These results highlight that the spatial modulation of metabolic pathways in Pinus koraiensis seeds underlies the germination response to ABA. [ABSTRACT FROM AUTHOR]

SUMMARY: Plant triacylglycerols (TAG) are used in food and various industrial feedstocks. LEAFY COTYLEDON 2 (LEC2), a master positive regulator of TAG biosynthesis, regulates a complex network of transcription factors (TFs) during seed development. Aside from WRINKLED1 (WRI1), the TFs regulated by LEC2 related to TAG biosynthesis have not yet been identified. Previously, we identified 25 seed‐expressing TFs that were upregulated in Arabidopsis leaves that overexpressed senescence‐induced LEC2. In this study, each of the 25 TFs was transiently expressed in the leaves of Nicotiana benthamiana to identify unknown TFs that regulate TAG biosynthesis. The TAG content of the transformed leaves was analyzed using thin layer chromatography and gas chromatography. We observed that five TFs, ARABIDOPSIS RESPONSIVE REGULATOR 21 (ARR21), AINTEGUMENTA‐LIKE 6 (AIL6), APETALA2/ETHYLENE RESPONSIVE FACTOR 55 (ERF55), WRKY DNA‐BINDING PROTEIN 8 (WRKY8), and ARABIDOPSIS NAC DOMAIN CONTAINING PROTEIN 38 (ANAC038) increased TAG synthesis in the leaves. Among these, the promoters of AIL6, ERF55, WRKY8, and ANAC038 contain RY motifs, which are LEC2‐binding sites activated by LEC2. AIL6 overexpression in Arabidopsis increased the total fatty acid (FA) content in seeds and altered the FA composition, with increases in 16:0, 18:1, and 18:2 and decreases in 18:0, 18:3, and 20:1 compared with those in the wild type (WT). AIL6 overexpression activates several FA and TAG biosynthesis genes. Therefore, our study successfully identified several new TFs regulated by LEC2 in TAG biosynthesis and showed that AIL6 increased the TAG content in seeds. [ABSTRACT FROM AUTHOR]

Qualea grandiflora Mart. is an aluminum (Al)‐accumulating Cerrado species with a metabolic dependency on Al. This study aimed to determine the presence and concentration of Al and other reserve components in Q. grandiflora seeds, as well as their respective distribution patterns, mobilization, and usage during germination and seedling growth. Thus, the concentration of Al and other minerals in seeds, seedlings, and soils was measured. Also, histochemical and energy‐dispersive X‐ray spectroscopy (EDS) analyses were performed to observe the distribution of Al, proteins, and lipids in Q. grandiflora seeds and seedlings. Additionally, the concentration of proteins and lipids was assessed as well. Hence, even in soils with low exchangeable Al3+, Q. grandiflora seeds accumulated about 6.43 g of Al/kg of dry matter (DM) together with considerable concentrations of N, P, K, Ca, and Mg. Exogenous Al had no effect on the germination properties of Q. grandiflora seeds. Furthermore, approximately 60% of the seed Al was translocated to seedling leaves. Proteins and lipids were the main organic reserves in Q. grandiflora seeds. The histochemical analysis revealed that the bulk of Al in seeds was in the cotyledons, which were also the location sites of proteins and lipids. Proteins and lipids were the primary source of energy and carbon for seedling growth. Therefore, fatty acids, proteins, and Al could play a central role during seed germination and seedling establishment, which could help to explain why this species is one of the most widespread plants in the Cerrado. [ABSTRACT FROM AUTHOR]

Pinus oocarpa is a widely distributed species essential for resin production in Mexico, where demand surpasses supply. This study aimed to identify differences and variation levels of seedling emergence capacity and morphological traits in resin-producing high-yield P. oocarpa trees and estimate their genetic control. Seeds from 72 open-pollinated families were planted using a randomized complete block experimental design. Differences between families were determined and pooled using cluster analysis. We recorded wide differences in seed emergence capacity and morphological traits (cotyledon number and length, and hypocotyl length), allowing to establish three family groups. We also calculated the contribution of the variation sources to the total variance and genetic parameters involved. Our data evidenced high genetic control for all tested variables. We found a moderate and positive genetic correlation between cotyledon length, cotyledon number, and hypocotyl length. We also found a high negative genetic correlation between emergence capacity and hypocotyl length. At the phenotypic level, we found a high and significant correlation between cotyledon length and number. Grouping P. oocarpa into families should aid decision-making for sexual propagation since a high propagation capacity of the high-yield trees is essential for genetic improvement programs. Moreover, we demonstrate that the heritability of the emergence capacity and other morphological traits is high; these traits can be useful for the early selection of high-yield families.

This study describes Siphoneugena carolynae (Myrtaceae), a new species from the Brazilian Atlantic Forest, in the state of Rio de Janeiro. The species inhabits inselberg forests and differs from all other species of Siphoneugena by the following exclusive combination of morphological characters: relatively long petioles, leaf blades chartaceous with midvein canaliculate adaxially, inflorescences in racemes with a markedly compressed and indistinguishable main axis, hypanthium markedly constricted above the ovary, calyx calyptrate, ovaries with two locules, each with four ovules, and cotyledons densely covered with foveolate glands. We herein provide taxonomic notes, morphological plates (derived from both fresh and dried material), and a distribution map. Regarding the conservation status, the new species is preliminarily assessed as Data Deficient (DD), but comments on population size and possible threats to the habitat are presented. [ABSTRACT FROM AUTHOR]

This study aims to establish an efficient protocol for protoplast isolation, cell division, and callus induction in two carnation cultivars, Chabaud and Giant Chabaud, by examining the influence of different types of plant tissue, enzyme concentrations, incubation times, cotyledon ages, and medium compositions. Our results indicate that protoplast yield varies significantly between different plant tissues, with true leaves offering the highest yield and viability, especially under a 0.1% driselase concentration and a 6-h incubation time. We observed that increasing the driselase concentration to 1.0% significantly reduced protoplast yields in all tissues tested. In addition, the age of the cotyledons notably affected protoplast yield, with younger cotyledons providing higher yields. The Murashige and Skoog medium supplemented with 1 mg/L zeatin and 1 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) proved to be the most effective for promoting cell division and colony formation from protoplasts derived from cotyledons and true leaves. The study also found that plant growth regulators (PGRs) significantly influence callus proliferation, with differences observed between protoplast sources. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Kirkuk University for Agricultural Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Phytoplasmas manipulate host plant development to benefit insect vector colonization and their own invasion. However, the virulence factors and mechanisms underlying small-leaf formation caused by jujube witches' broom (JWB) phytoplasmas remain largely unknown. Here, effectors SJP1 and SJP2 from JWB phytoplasmas were identified to induce small-leaf formation in jujube (Ziziphus jujuba). In vivo interaction and expression assays showed that SJP1 and SJP2 interacted with and stabilized the transcription factor ZjTCP2. Overexpression of SJP1 and SJP2 in jujube induced ZjTCP2 accumulation. In addition, the abundance of miRNA319f_1 was significantly reduced in leaves of SJP1 and SJP2 transgenic jujube plants and showed the opposite pattern to the expression of its target, ZjTCP2 , which was consistent with the pattern in diseased leaves. Overexpression of ZjTCP2 in Arabidopsis promoted ectopic leaves arising from the adaxial side of cotyledons and reduced leaf size. Constitutive expression of the miRNA319f_1 precursor in the 35S::ZjTCP2 background reduced the abundance of ZjTCP2 mRNA and reversed the cotyledon and leaf defects in Arabidopsis. Therefore, these observations suggest that effectors SJP1 and SJP2 induced small-leaf formation, at least partly, by interacting with and activating ZjTCP2 expression both at the transcriptional and the protein level, providing new insights into small-leaf formation caused by phytoplasmas in woody plants. [ABSTRACT FROM AUTHOR]

Summary: The potential for totipotency exists in all plant cells; however, the underlying mechanisms remain largely unknown. Earlier findings have revealed that the overexpression of LEAFY COTYLEDON 2 (LEC2) can directly trigger the formation of somatic embryos on the cotyledons of Arabidopsis. Furthermore, cotyledon cells that overexpress LEC2 accumulate significant lipid reserves typically found in seeds. The precise mechanisms and functions governing lipid accumulation in this process remain unexplored.In this study, we demonstrate that WRINKLED1 (WRI1), the key regulator of lipid biosynthesis, is essential for somatic embryo formation, suggesting that WRI1‐mediated lipid biosynthesis plays a crucial role in the transition from vegetative to embryonic development.Our findings indicate a direct interaction between WRI1 and LEC2, which enhances the enrichment of LEC2 at downstream target genes and stimulates their induction. Besides, our data suggest that WRI1 forms a complex with LEC1, LEC2, and FUSCA3 (FUS3) to facilitate the accumulation of auxin and lipid for the somatic embryo induction, through strengthening the activation of YUCCA4 (YUC4) and OLEOSIN3 (OLE3) genes.Our results uncover a regulatory module controlled by WRI1, crucial for somatic embryogenesis. These findings provide valuable insights into our understanding of plant cell totipotency. [ABSTRACT FROM AUTHOR]

As sessile organisms, land plants experience various forms of environmental stresses throughout their life span. Therefore, plants have developed extensive and complicated defense mechanisms, including a robust DNA damage response (DDR) and DNA repair systems for maintaining genome integrity. In Arabidopsis , the NAC [NO APICAL MERISTEM (NAM), ARABIDOPSIS TRANSCRIPTION ACTIVATION FACTOR (ATAF), CUP-SHAPED COTYLEDON (CUC)] domain family transcription factor SUPPRESSOR OF GAMMA RESPONSE 1 (SOG1) plays an important role in regulating DDR. Here, we show that SOG1 plays a key role in regulating the repair of salinity-induced DNA double-strand breaks (DSBs) via the homologous recombination (HR) pathway in Arabidopsis. The sog1-1 mutant seedlings display a considerably slower rate of repair of salinity-induced DSBs. Accumulation of SOG1 protein increases in wild-type Arabidopsis under salinity stress, and it enhances the expression of HR pathway–related genes, including RAD51, RAD54 and BReast CAncer gene 1 (BRCA1), respectively, as found in SOG1 overexpression lines. SOG1 binds specifically to the AtRAD54 promoter at the 5ʹ-(N)4GTCAA(N)3C-3ʹ consensus sequence and positively regulates its expression under salinity stress. The phenotypic responses of sog1-1/atrad54 double mutants suggest that SOG1 functions upstream of RAD54 , and both these genes are essential in regulating DDR under salinity stress. Furthermore, SOG1 interacts directly with BRCA1, an important component of the HR-mediated DSB repair pathway in plants, where BRCA1 appears to facilitate the binding of SOG1 to the RAD54 promoter. At the genetic level, SOG1 and BRCA1 function interdependently in modulating RAD54 expression under salinity-induced DNA damage. Together, our results suggest that SOG1 regulates the repair of salinity-induced DSBs via the HR-mediated pathway through genetic interactions with RAD54 and BRCA1 in Arabidopsis. [ABSTRACT FROM AUTHOR]

Auxin plays a key role in plant growth and development through auxin local synthesis, polar transport, and auxin signaling. Many previous reports on Arabidopsis have found that various types of auxin‐related genes are involved in the development of the cotyledon, including the number, symmetry, and morphology of the cotyledon. However, the molecular mechanism by which auxin is involved in cotyledon formation remains to be elucidated. PID, which encodes a serine/threonine kinase localized to the plasma membrane, has been found to phosphorylate the PIN1 protein and regulate its polar distribution in the cell. The loss of function of pid resulted in an abnormal number of cotyledons and defects in inflorescence. It was interesting that the pid mutant interacted synergistically with various types of mutant to generate the severe developmental defect without cotyledon. PID and these genes were indicated to be strongly correlated with cotyledon formation. In this review, PID‐centered genetic interactions, related gene functions, and corresponding possible pathways are discussed, providing a perspective that PID and its co‐regulators control cotyledon formation through multiple pathways. [ABSTRACT FROM AUTHOR]

Leaf color is one of the most important phenotypic features in horticultural crops and directly related to the contents of photosynthetic pigments. Most leaf color mutants are determined by the altered chlorophyll or carotenoid, which can be affected by light quality and intensity. Our previous study obtained a Chinese cabbage yellow cotyledon mutant that exhibited obvious yellow phenotypes in the cotyledons and the new leaves. However, the underlying mechanisms in the formation of yellow cotyledons and leaves remain unclear. In this study, the Chinese cabbage yellow cotyledon mutant 19YC-2 exhibited obvious difference in leaf color and abnormal chloroplast ultrastructure compared to the normal green cotyledon line 19GC-2. Remarkably, low-intensity light treatment caused turn-green leaves and a significant decrease in carotenoid content in 19YC-2. RNA-seq analysis revealed that the pathways of photosynthesis antenna proteins and carotenoid biosynthesis were significantly enriched during the process of leaf color changes, and many differentially expressed genes related to the two pathways were identified to respond to different light intensities. Remarkably, BrPDS and BrLCYE genes related to carotenoid biosynthesis showed significantly higher expression in 19YC-2 than that in 19GC-2, which was positively related to the higher carotenoid content in 19YC-2. In addition, several differentially expressed transcription factors were also identified and highly correlated to the changes in carotenoid content, suggesting that they may participate in the regulatory pathway of carotenoid biosynthesis. These findings provide insights into the molecular mechanisms of leaf color changes in yellow cotyledon mutant 19YC-2 of Chinese cabbage. [ABSTRACT FROM AUTHOR]

Polycotyly, an interesting characteristic of seed-bearing dicotyledonous plants with more than two cotyledons, represents one of the least explored plant characters for utilization, even though cotyledon number was used to classify flowering plants in 1682. Gymnosperm and angiosperm species are generally known to have one or two cotyledons, but scattered reports exist on irregular cotyledon numbers in many plant species, and little is known about the extent of polycotyly in plant taxa. Here, we attempt to update the documentation of reports on polycotyly in plant species and highlight some lines of research for a better understanding of polycotyly. This effort revealed 342 angiosperm species of 237 genera in 80 (out of 416) families and 160 gymnosperm species of 26 genera in 6 (out of 12) families with reported or cited polycotyly. The most advanced research included the molecular-based inference of the phylogeny of flowering plants, showing a significant departure from the cotyledon-based classification of angiosperm plants, and the application of genetic cotyledon mutants as tools to clone and characterize the genes regulating cotyledon development. However, there were no reports on breeding lines with a 100% frequency of polycotyly. Research is needed to discover plant species with polycotyly and to explore the nature, development, genetics, evolution, and potential use of polycotyly. [ABSTRACT FROM AUTHOR]

Chalcone isomerase (CHI) is an important enzyme involved in the biosynthesis of flavonoids, one that is crucial in both plant defense and human health. Although many CHI genes have been previously identified, the function of CHI-like genes in soybean remains unclear. In this study, we cloned the CHI-like genes GmCHI4A and GmCHI4B (GmCHI4s) in soybean. The real-time quantitative polymerase chain reaction showed that GmCHI4s were expressed primarily in soybean root, but were also present in other tissues, including the stem, leaf, and seed with a low expression level. Overexpression of GmCHI4s was able to significantly improve some beneficial traits of the transformed hair roots of cotyledon or composite plants under salt stress conditions. Root length, root wet weight, and the underground biomass was increased, and the elevation of MDA content was inhibited under 100 mmol L−1 or 150 mmol L−1 NaCl treatment. Leaf chlorophyll content was elevated in overexpressed GmCHI4A composite plants under 150 mmol L−1 NaCl treatment. The expression levels of salt-stress-related genes GmSOD1, GmAPX1, GmSOS1, and GmNHX1 were significantly upregulated in overexpressed GmCHI4 hairy roots compared to that in empty-vector-expressed hairy roots. The above results indicated GmCHI4s' potential action against salt stress. Furthermore, overexpression of GmCHI4A and GmCHI4B increased the total isoflavone content by six times and three times, respectively. Glycitin and glycitein levels were significantly elevated in the overexpressed GmCHI4A hairy roots, while glycitin, genistin, daidzein, and genistein were significantly increased in overexpressed GmCHI4B hairy roots. This study identified a new function of the CHI-like gene, as well as providing a new selected gene for salt tolerance and isoflavone improvement using biotechnological approaches in soybean. [ABSTRACT FROM AUTHOR]

In the present study, bioactive compounds were extracted from cotyledon of bitter orange (Citrus aurantium) seed, as a waste of citrus processing, using a microwave-assisted extraction method. The effects of four independent variables including microwave power (100-300 W), extraction time (5-15 min), sample weight (5-15 g), and solvent volume (100-200 mL) on responses of extraction yield, total phenolic content, total flavonoid content, free radical scavenging activity (ICs), ferric ion reducing antioxidant power (FRAP), cupric ion reducing antioxidant capacity (CUPRAC), and chelating capacity of extracts were investigated. Response surface methodology based on the central composite design was employed to investigate the effects of independent variables on the responses and also to optimize the extraction conditions. The optimum extraction condition included microwave power of 300 W, extraction time of 15 min, sample weight of 5 g, and solvent volume of 200 mL. Regarding the extraction yield, its amount increased significantly by increasing microwave power, extraction time, and sample weight, while it decreased significantly by increasing solvent volume. Also, the highest total phenolic content in the extract was observed at the lowest levels of microwave power and extraction time. Concerning the total flavonoid content in the extract, its amount increased significantly by increasing extraction time and solvent volume, while it decreased significantly by increasing sample weight. In addition, the CUPRAC of the extract increased significantly by increasing microwave power, extraction time, and solvent volume, as opposed to sample weight. In conclusion, microwave-assisted extraction can be suggested as a suitable method for extracting bioactive compounds from the bitter orange seed cotyledon. [ABSTRACT FROM AUTHOR]

The numerous votive uteri found across the central Italian peninsula from the fourth to first centuries BCE are puzzlingly evocative of the human simplex uterus, which is visually distinct from the bicornuate uteri characteristic of most other mammals. However, human dissection is not attested for this time and place, while animal butchery was common. This article uses modern veterinary anatomical imagery to argue that animal uteri — specifically as they appear when pregnant — were indeed models underlying the votive depictions. Some of the variant forms of the votives are highly evocative of various features of the pregnant bicornuate uterus. Further, medical views on the human uterus throughout classical antiquity were informed by animal uteri. Taken together, the visual and textual evidence indicate that animal models were inextricably integrated into ancient conceptions of the human uterus across the classical world, including in the production of the Italic votives in question. [ABSTRACT FROM AUTHOR]

Programmed cell death (PCD) is a fundamental cellular process crucial to development, homeostasis, and immunity in multicellular eukaryotes. In contrast to our knowledge on the regulation of diverse animal cell death subroutines, information on execution of PCD in plants remains fragmentary. Here, we make use of the accessibility of the Arabidopsis (Arabidopsis thaliana) root cap to visualize the execution process of developmentally controlled PCD. We identify a succession of selective decompartmentalization events and ion fluxes as part of the terminal differentiation program that is orchestrated by the NO APICAL MERISTEM, ARABIDOPSIS THALIANA ACTIVATING FACTOR, CUP-SHAPED COTYLEDON (NAC) transcription factor SOMBRERO. Surprisingly, the breakdown of the large central vacuole is a relatively late and variable event, preceded by an increase of intracellular calcium levels and acidification, release of mitochondrial matrix proteins, leakage of nuclear and endoplasmic reticulum lumina, and release of fluorescent membrane reporters into the cytosol. In analogy to animal apoptosis, the plasma membrane remains impermeable for proteins during and after PCD execution. Elevated intracellular calcium levels and acidification are sufficient to trigger cell death execution specifically in terminally differentiated root cap cells, suggesting that these ion fluxes act as PCD-triggering signals. This detailed information on the cellular processes occurring during developmental PCD in plants is a pivotal prerequisite for future research into the molecular mechanisms of cell death execution. Live-cell imaging of the Arabidopsis root cap reveals a series of developmentally controlled cellular decompartmentalization events occurring during the execution of programmed cell death. [ABSTRACT FROM AUTHOR]

Identification of signaling pathways that control C4 photosynthesis development is essential for introducing the C4 pathway into C3 crops. Species with dual photosynthesis in their life cycle are interesting models to study such regulatory mechanisms. The species used here Halimocnemis mollissima Bunge, belonging to the Caroxyleae tribe, displays C3 photosynthesis in its cotyledons and a NAD-ME subtype of C4 photosynthesis in the First leaves (FLs) onwards. We explored the long-distance signaling pathways that are probably implicated in the shoot–root coordination associated with the manifestation of the C4 traits, including efficient resource usage by comparing the mRNA content of hypocotyls before and after the C4 first leave's formation. Histological examination showed the presence of C3 anatomy in cotyledons and C4 anatomy in the FLs. Our transcriptome analyses verified the performance of the NAD-ME subtype of C4 in FLs and revealed differential transcript abundance of several potential mobile regulators and their associated receptors or transporters in two developmentally different hypocotyls of H. mollissima Bunge. These differentially expressed genes (DEGs) belong to diverse functional groups, including various transcription factor (TF) families, phytohormones metabolism, and signaling peptides, part of which could be related to hypocotyl development. Our findings support the higher nitrogen and water use efficiency associated with C4 photosynthetic and provide insights into the coordinated above- and under-ground tissue communication during the developmental transition of C3–C4 photosynthesis in this species. [ABSTRACT FROM AUTHOR]

In commercial forestry and large-scale plant propagation, the utilization of artificial intelligence techniques for automated somatic embryo analysis has emerged as a highly valuable tool. Notably, image segmentation plays a key role in the automated assessment of mature somatic embryos. However, to date, the application of Convolutional Neural Networks (CNNs) for segmentation of mature somatic embryos remains unexplored. In this study, we present a novel application of CNNs for delineating mature somatic conifer embryos from background and residual proliferating embryogenic tissue and differentiating various morphological regions within the embryos. A semantic segmentation CNN was trained to assign pixels to cotyledon, hypocotyl, and background regions, while an instance segmentation network was trained to detect individual cotyledons for automated counting. The main dataset comprised 275 high-resolution microscopic images of mature Pinus radiata somatic embryos, with 42 images reserved for testing and validation sets. The evaluation of different segmentation methods revealed that semantic segmentation achieved the highest performance averaged across classes, achieving F1 scores of 0.929 and 0.932, with IoU scores of 0.867 and 0.872 for the cotyledon and hypocotyl regions respectively. The instance segmentation approach demonstrated proficiency in accurate detection and counting of the number of cotyledons, as indicated by a mean squared error (MSE) of 0.79 and mean absolute error (MAE) of 0.60. The findings highlight the efficacy of neural network-based methods in accurately segmenting somatic embryos and delineating individual morphological parts, providing additional information compared to previous segmentation techniques. This opens avenues for further analysis, including quantification of morphological characteristics in each region, enabling the identification of features of desirable embryos in large-scale production systems. These advancements contribute to the improvement of automated somatic embryogenesis systems, facilitating efficient and reliable plant propagation for commercial forestry applications. [ABSTRACT FROM AUTHOR]

Grafting onto pumpkin rootstock is widely applied in cucumber production to improve growth and yield, as well as to overcome soil-borne diseases and enhance resistance to abiotic stresses. In this study, we constructed the cucumber-pumpkin heterografts with the one-cotyledon grafting method, and examined the effects of heterografting on biomass allocation and sugar partitioning, with cucumber and pumpkin self-grafts used as control. Compared with cucumber self-grafts, heterografting onto pumpkin rootstock promoted photosynthesis in cucumber scion, and led to higher sucrose contents in the 1st true leaf (source) and newly emerged leaf (sink). Thereby, the scion part of heterografts accumulated more biomass than cucumber self-grafts. In contrast, when compared to pumpkin self-grafts, grafting with cucumber scion reduced root vigor and biomass but promoted cotyledon growth in pumpkin rootstock. The roots (sink) of heterografts contained less sucrose and hexoses, and showed reduced sucrose synthase (SuSy) and hexokinase (HXK) activities. However, the rootstock cotyledon (source) contained more sucrose and starch, and showed higher activities of HXK, cell-wall invertase (CWIN), and enzymes for starch synthesis and degradation. Furthermore, removal or shade of rootstock cotyledon led to reduced growth of root and scion. Silencing of CmoMEX1a gene in rootstock cotyledon inhibited maltose export and reduced root growth of heterografts. These results indicated that rootstock cotyledon, especially its starch content, played a buffering role in the growth regulation of cucumber-pumpkin heterografts. Taken together, our results provided a major contribution to our understanding of source-sink sugar partitioning and scion-rootstock growth balancing in cucumberpumpkin heterografts. [ABSTRACT FROM AUTHOR]

• Exogenous IAA (25 µM) and/or H 2 O 2 (350 µM) regulates seedling growth, Na+/K+ homeostasis, and H 2 S metabolism in etiolated sunflower seedlings. • Exogenous auxin (IAA) and/or H 2 O 2 treatment recovered both root length and lateral root proliferation under NaCl stress (120 mM). • IAA and H 2 O 2 modules H 2 S content in seedling roots and cotyledons and impact l -DES activity. • TIBA disrupts the internal auxin gradient in roots and reverse the positive effects of exogenous IAA. Although H 2 S has been reported to modulate auxin and H 2 O 2 signaling during abiotic stress, no reports decipher the interactive roles of exogenous auxin and H 2 O 2 on the regulation of endogenous H 2 S homeostasis. In the present work, auxin (IAA) and hydrogen peroxide (H 2 O 2) interaction appear to be crucial in regulating Na+/K+ homeostasis, recovery in seedling growth and H 2 S accumulation in NaCl-stressed sunflower seedlings. Interestingly, impairment in endogenous IAA transport (TIBA application) also impacts H 2 S accumulation in the roots and cotyledons. IAA supplementation is effective in reducing Na+/K+ ratio and electrolytic leakage in roots, which reverses in the presence of TIBA (polar auxin transport inhibitor) application. IAA and H 2 O 2 -mediated modulation of H 2 S content corroborates with l -DES activity in seedling roots and cotyledons. In contrast to cotyledons, roots exhibited a reduction in H 2 S content in the presence of treatments (IAA and H 2 O 2). H 2 O 2 supplementation seems to partially circumvent the changes caused by the disruption of auxin transport. Thus, we hypothesize that auxin might imply H 2 O 2 as a crucial signaling component in the regulation of H 2 S levels in sunflower tissues. To sum up, IAA and H 2 O 2 interaction regulates root growth, LR proliferation, Na+/K+ ratio, and H 2 S metabolism in sunflower seedling roots. [ABSTRACT FROM AUTHOR]

Pinus oocarpa is the most important conifer for resin production in Mexico, so superior resin trees were selected in the Southern Mountains of Oaxaca, Mexico. The objective was to determine the variation and differences among provenances and among trees according to the parameters of seedling emergence and the number of cotyledons, and their relationship with elevation and climatic variables. The seedling emergence of four replicates of 20 seeds from 80 trees was counted daily. For the emergence parameters, provenance contributed 42.02% to the total variance, tree 29.19% and error 28.79%. Only tree (11.71%) and error (88.29%) contributed to the total variance of the cotyledon number. The effect of provenance (p ≤ 0.0006) and tree (p ≤ 0.0001) was significant for all variables evaluated. Higher-elevation provenances and trees had higher emergence values. The emergence parameters were positively associated with tree elevation. Climatic variables related to precipitation and temperature were negatively related to the emergence parameters. The results allow for the selection of phenotypes without emergence problems to establish seed orchards. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agriculture & Nature / Kahramanmaraş Sütçü İmam Üniversitesi Tarım & Doğa Dergisi is the property of Kahramanmaras Sutcu Imam Universitesi and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

WUSCHEL-related homeobox (WOX) genes are a class of plant-specific transcription factors, regulating the development of multiple tissues. However, the genomic characterizations and expression patterns of WOX genes have not been analyzed in lotus. In this study, 15 NnWOX genes were identified based on the well-annotated reference genome of lotus. According to the phylogenetic analysis, the NnWOX genes were clustered into three clades, i.e., ancient clade, intermediate clade, and WUS clade. Except for the conserved homeobox motif, we further found specific motifs of NnWOX genes in different clades and divergence gene structures, suggesting their distinct functions. In addition, two NnWOX genes in the ancient clade have conserved expression patterns and other NnWOX genes exhibit different expression patterns in lotus tissues, suggesting a low level of functional redundancy in lotus WOX genes. Furthermore, we constructed the gene co-expression networks for each NnWOX gene. Based on weighted gene co-expression network analysis (WGCNA), ten NnWOX genes and their co-expressed genes were assigned to the modules that were significantly related to the cotyledon and seed coat. We further performed RT-qPCR experiments, validating the expression levels of ten NnWOX genes in the co-expression networks. Our study reveals comprehensive genomic features of NnWOX genes in lotus, providing a solid basis for further function studies. [ABSTRACT FROM AUTHOR]

Placental abnormalities more frequently occur during pregnancy of somatic cell clones and may lead to pregnancy loss or dystocia. Adventitious placentation, or diffuse semi-placenta, is determined by the development of areas of accessory placentation between the cotyledons due to the abnormal growth of placentomes. After a full-term pregnancy, a 3-year-old Jersey heifer was referred for dystocia which resulted in the delivery of a dead calf. The cause of dystocia was found to be foetal malposition, while the placenta was physiologically expelled after dystocia resolution. Grossly, cotyledons appeared reduced in size and number in one placental horn, while the surface of the other horn was covered with microplacentomes. Numerous villous structures without trophoblastic coating were highlighted after histopathology. The dominant sign was an inflammatory reaction. The findings were consistent with inter-cotyledonal placentitis, which led to adventitial placentation. Diffuse semi-placenta compensates for the inadequate development of placentomes and may occur as a congenital or acquired defect. The outcome depends on its severity: in the worst scenario, pregnancy may not proceed beyond midterm and may be complicated by hydrallantois. In the case under examination, the dimensions of the cotyledons (from 2 to 10 cm) allowed for the natural course of pregnancy. [ABSTRACT FROM AUTHOR]

Simple Summary: Understanding placental vascularity is vital for ensuring the proper nourishment of the fetus and, therefore, a healthy offspring. We aimed to investigate the impact of vitamin and mineral supplementation and/or different rates of body weight gain on placental vascularity in beef heifers. To this end, in the first experiment, heifers were divided into groups that received vitamin and mineral supplementation or did not at least 72 days before breeding. At breeding, they were further divided into low or moderate-weight gain groups, resulting in four different treatments maintained until day 83 of pregnancy when tissue collection was performed. In the second experiment, another group of heifers received a basal diet or a diet with vitamin and mineral supplementation from breeding until parturition. We evaluated placental blood vessel density in both experiments and the placental expression of genes related to blood vessel growth in the first experiment. Results showed that supplementation and the rate of body weight gain during early pregnancy did not significantly affect placental vascularity or the expression of angiogenic factors. On the other hand, placental vascularity measured at parturition was increased in the fetal placenta of the supplemented group. These findings suggest that supplementation with vitamins and minerals throughout all gestation may impact placental function at a later stage of pregnancy. The effect of vitamins and minerals supplementation (VTM) and/or two rates of body weight gain (GAIN) on bovine placental vascular development and angiogenic factors gene expression were evaluated in two experiments: In Exp. 1, crossbred Angus heifers (n = 34) were assigned to VTM/NoVTM treatments at least 71 days before breeding to allow changes in the mineral status. At breeding, through artificial insemination (AI), heifers were assigned to low-gain (LG) 0.28 kg/d or moderate-gain (MG) 0.79 kg/d treatments, resulting in NoVTM-LG (Control; n = 8), NoVTM-MG (n = 8), VTM-LG (n = 9), and VTM-MG (n = 9) until day 83 of gestation; In Exp. 2, crossbred angus heifers (n = 28), were assigned to control (CON; n = 12), receiving a basal total mixed ration (TMR) or TMR + VTM (VTM; n = 16) from breeding until parturition. Placentomes from Exp. 1 and cotyledons (COT) from Exp. 2 were evaluated by immunohistochemistry for COT vascular density area. COTs from Exp. 1 were evaluated for angiogenic factor (ANGPT-1, ANGPT-2, eNOS2, eNOS3, FLT1, KDR, TEK, VEGFA) gene expression. In Exp. 1, COT vascularity was not affected by the interaction of VTM and GAIN (p = 0.67) or the main effects of VTM (p = 0.50) and GAIN (p = 0.55). Likewise, angiogenic factors were not differentially expressed between treatments (p < 0.05). In Exp. 2, COT vascularity was greater in VTM vs. CON (p = 0.07). In conclusion, there is a suggested later-stage influence of vitamin and mineral supplementation on placental vascularity, emphasizing the importance of supplementation beyond early pregnancy. [ABSTRACT FROM AUTHOR]

Summary: During abscisic acid (ABA) signaling, reversible phosphorylation controls the activity and accumulation of class III SNF1‐RELATED PROTEIN KINASE 2s (SnRK2s). While protein phosphatases that negatively regulate SnRK2s have been identified, those that positively regulate ABA signaling through SnRK2s are less understood.In this study, Arabidopsis thaliana mutants of Clade E Growth‐Regulating 1 and 2 (EGR1/2), which belong to the protein phosphatase 2C family, exhibited reduced ABA sensitivity in terms of seed germination, cotyledon greening, and ABI5 accumulation. Conversely, overexpression increased these ABA‐induced responses. Transcriptomic data revealed that most ABA‐regulated genes in egr1 egr2 plants were expressed at reduced levels compared with those in Col‐0 after ABA treatment.Abscisic acid up‐regulated EGR1/2, which interact directly with SnRK2.2 through its C‐terminal domain I. Genetic analysis demonstrated that EGR1/2 function through SnRK2.2 during ABA response. Furthermore, SnRK2.2 de‐phosphorylation by EGR1/2 was identified at serine 31 within the ATP‐binding pocket. A phospho‐mimic mutation confirmed that phosphorylation at serine 31 inhibited SnRK2.2 activity and reduced ABA responsiveness in plants.Our findings highlight the positive role of EGR1/2 in regulating ABA signaling, they reveal a new mechanism for modulating SnRK2.2 activity, and provide novel insight into how plants fine‐tune their responses to ABA. [ABSTRACT FROM AUTHOR]

A large seed mutant, TG 89 having a 76.7% increment in hundred kernel weight in comparison to its parent TG 26, was isolated from an electron beam-induced mutagenized population. Studies based on environmental scanning electron microscopy of both parent and mutant revealed that the mutant seed cotyledon had significantly bigger cell size than parent. A mapping population with 122 F2 plants derived from the mutant and a distant normal seed genotype (ICGV 15007) was utilized to map the QTL associated with higher HKW. Bulk segregant analysis revealed putative association of three markers with this mutant large seed trait. Further, genotyping of F2 individuals with polymorphic markers detected 14 linkage groups with a map distance of 1053 cM. QTL analysis revealed a significant additive major QTL for the mutant large seed trait on linkage group A05 explaining 12.7% phenotypic variation for the seed size. This QTL was located between flanking markers AhTE333 and AhTE810 having a map interval of 4.7 cM which corresponds to 90.65 to 107.24 Mbp in A05 chromosome, respectively. Within this genomic fragment, an ortholog of the BIG SEEDS 1 gene was found at 102,476,137 bp. Real-time PCR revealed down-regulation of this BIG SEEDS 1 gene in the mutant indicating a loss of function mutation giving rise to a large seed phenotype. This QTL was validated in 11 advanced breeding lines having large seed size from this mutant but with varied genetic backgrounds. This validation showcased a highly promising selection accuracy of 90.9% for the marker-assisted selection. [ABSTRACT FROM AUTHOR]

Drought stress can seriously affect the yield and quality of wheat (Triticum aestivum). So far, although few wheat heat shock transcription factors (Hsfs) have been found to be involved in the stress response, the biological functions of them, especially the members of the HsfC (heat shock transcription factor C) subclass, remain largely unknown. Here, we identified a class C encoding gene, TaHsfC3-4, based on our previous omics data and analyzed its biological function in transgenic plants. TaHsfC3-4 encodes a protein containing 274 amino acids and shows the basic characteristics of the HsfC class. Gene expression profiles revealed that TaHsfC3-4 was constitutively expressed in many tissues of wheat and was induced during seed maturation. TaHsfC3-4 could be upregulated by PEG and abscisic acid (ABA), suggesting that this Hsf may be involved in the regulation pathway depending on ABA in drought resistance. Further results represented that TaHsfC3-4 was localized in the nucleus but had no transcriptional activation activity. Notably, overexpression of TaHsfC3-4 in Arabidopsis thaliana pyr1pyl1pyl2pyl4 (pyr1pyl124) quadruple mutant plants complemented the ABA-hyposensitive phenotypes of the quadruple mutant including cotyledon greening, root elongation, seedling growth, and increased tolerance to drought, indicating positive roles of TaHsfC3-4 in the ABA signaling pathway and drought tolerance. Furthermore, we identified TaHsfA2-11 as a TaHsfC3-4-interacting protein by yeast two-hybrid (Y2H) screening. The experimental data show that TaHsfC3-4 can indeed interact with TaHsfA2-11 in vitro and in vivo. Moreover, transgenic Arabidopsis TaHsfA2-11 overexpression lines exhibited enhanced drought tolerance, too. In summary, our study confirmed the role of TaHsfC3-4 in response to drought stress and provided a target locus for marker-assisted selection breeding to improve drought tolerance in wheat. [ABSTRACT FROM AUTHOR]

Transcription factors (TFs) are diverse groups of regulatory proteins. Through their specific binding domains, TFs bind to their target genes and regulate their expression, therefore TFs play important roles in various growth and developmental processes. Plant embryogenesis is a highly regulated and intricate process during which embryos arise from various sources and undergo development; it can be further divided into zygotic embryogenesis (ZE) and somatic embryogenesis (SE). TFs play a crucial role in the process of plant embryogenesis with a number of them acting as master regulators in both ZE and SE. In this review, we focus on the master TFs involved in embryogenesis such as BABY BOOM (BBM) from the APETALA2/Ethylene-Responsive Factor (AP2/ERF) family, WUSCHEL and WUSCHEL-related homeobox (WOX) from the homeobox family, LEAFY COTYLEDON 2 (LEC2) from the B3 family, AGAMOUS-Like 15 (AGL15) from the MADS family and LEAFY COTYLEDON 1 (LEC1) from the Nuclear Factor Y (NF-Y) family. We aim to present the recent progress pertaining to the diverse roles these master TFs play in both ZE and SE in Arabidopsis, as well as other plant species including crops. We also discuss future perspectives in this context. [ABSTRACT FROM AUTHOR]