Search

Patchouli (Pogostemon cablin) is an aromatic plant, and its oil has diverse applications in medicine, food, and cosmetics. Patchouli alcohol is the principal bioactive constituent of its volatile oil. In China, patchouli is typically categorized into two types: patchoulol-type (PA-type) and pogostone-type (PO-type). The study evaluated physiological and biochemical indicators, phytohormone metabolites and conducted transcriptome and proteome analyses on both two chemotypes. The PA-type exhibited higher levels of chlorophyll a, b, and carotenoids than the PO-type. In total, 35 phytohormone metabolites representing cytokinin, abscisic acid, gibberellin, jasmonic acid, and their derivatives were identified using UPLC-MS/MS, 10 of which displayed significant differences, mainly belong to cytokinins and jasmonates. Transcriptome analysis identified 4,799 differentially expressed genes (DEGs), while proteome analysis identified 150 differentially expressed proteins (DEPs). Regarding the transcriptome results, the DEGs of the PO-type showed significant downregulation in the pathways of photosynthesis, photosynthesis-antenna protein, porphyrin and chlorophyll metabolism, carotenoid biosynthesis, sesquiterpene and triterpenoid biosynthesis, and starch and sucrose metabolism, but upregulation in the pathway of zeatin synthesis. A combination of transcriptome and proteome analyses revealed that the DEGs and DEPs of lipoxygenase (LOX2), β-glucosidase, and patchouli synthase (PTS) were collectively downregulated, while the DEGs and DEPs of Zeatin O-xylosyltransferase (ZOX1) and α-amylase (AMY) were jointly upregulated in the PO-type compared to the PA-type. Differential levels of phytohormones, variations in photosynthetic efficiency, and differential expression of genes in the sesquiterpene synthesis pathway may account for the morphological and major active component differences between the two chemotypes of patchouli. The findings of this study offer novel perspectives on the underlying mechanisms contributing to the formation of the two patchouli chemotypes. [ABSTRACT FROM AUTHOR]

Poor grain-filling initiation in inferior spikelets severely impedes rice yield improvement, while photo-assimilates from source leaves can greatly stimulate the initiation of inferior grain-filling (sink). To investigate the underlying mechanism of source-sink interaction, a two-year field experiment was conducted in 2019 and 2020 using two large-panicle rice cultivars (CJ03 and W1844). The treatments included intact panicles and partial spikelet removal. These two cultivars showed no significant difference in the number of spikelets per panicle. However, after removing spikelet, W1844 showed higher promotion on 1000-grain weight and seed-setting rate than CJ03, particularly for inferior spikelets. The reason was that the better sink activity of W1844 led to a more effective initiation of inferior grain-filling compared to CJ03. The inferior grain weight of CJ03 and W1844 did not show a significant increase until 8 days poster anthesis (DPA), which follows a similar pattern to the accumulation of photo-assimilates in leaves. After removing spikelets, the source leaves of W1844 exhibited lower photosynthetic inhibition compared to CJ03, as well as stronger metabolism and transport of photo-assimilates. Although T6P levels remained constant in both cultivars under same conditions, the source leaves of W1844 showed notable downregulation of SnRK1 activity and upregulation of phytohormones (such as abscisic acid, cytokinins, and auxin) after removing spikelets. Hence, the high sink strength of inferior spikelets plays a role in triggering the enhancement of source strength in rice leaves, thereby fulfilling grain-filling initiation demands. [ABSTRACT FROM AUTHOR]

To improve the fruit quality of deep-netted melon, fish protein peptide (FPP) with a total protein content greater than 90% at a concentration of 1 g·L−1 was sprayed on leaves after pollination, distilled water was sprayed on the control plants (CK). Field indices such as single melon fresh mass, commercial fruit rate, yield and fruit nutrient contents were evaluated. Soluble sugar, starch, organic acid and the activities of enzymes related to sugar metabolism in the inner, middle and outer layers of melon flesh were also determined. The results showed that the commercial fruit rate and yield per hectare increased by 8.96% and 5.98%, respectively. Nutrient contents increased, including the total amounts of 16 amino acids were 0.34 g/100 g higher than those of CK, and the mineral element contents increased by 15.79%, among which the contents of potassium, phosphorus, zinc, calcium, magnesium and molybdenum were significantly different from those of CK (p < 0.05). FPP treatment significantly increased the soluble sugar content in the outer layer of the mesocarp of deep-netted melon and the ascorbic acid contents in the inner and middle layers of the mesocarp of deep-netted melon. FPP increased sucrose accumulations in fruit by decreasing the activity of neutral invertase (NI), increasing the activity of sucrose phosphate synthase (SPS) and the synthesis direction of sucrose synthase (SS), and by increasing the glucose and fructose contents by enhancing the activity of acid invertase (AI). These findings suggest that exogenous FPP improves the commercial fruit rate, yield, and quality of deep-netted melon. [ABSTRACT FROM AUTHOR]

Cytokinins (CKs) are phytohormones that promote cell division and differentiation. However, the regulation of CK distribution and homeostasis in Brassica napus is poorly understood. Here, the endogenous CKs were first quantified by LC-ESI-MS/MS in rapeseed tissues and visualized by TCSn::GUS reporter lines. Interestingly, the cytokinin oxidase/dehydrogenase BnaCKX2 homologs were mainly expressed in reproductive organs. Subsequently, the quadruple mutants of the four BnaCKX2 homologs were generated. Endogenous CKs were increased in the seeds of the BnaCKX2 quadruple mutants, resulting in a significantly reduced seed size. In contrast, overexpression of BnaA9.CKX2 resulted in larger seeds, probably by delaying endosperm cellularization. Furthermore, the transcription factor BnaC6.WRKY10b, but not BnaC6.WRKY10a, positively regulated BnaA9.CKX2 expression by binding directly to its promoter region. Overexpression of BnaC6.WRKY10b rather than BnaC6.WRKY10a resulted in lower concentration of CKs and larger seeds by activating BnaA9.CKX2 expression, indicating that the functional differentiation of BnaWRKY10 homologs might have occurred during B. napus evolution or domestication. Notably, the haploid types of BnaA9.CKX2 were associated with 1000-seed weight in the natural B. napus population. Overall, the study reveals the distribution of CKs in B. napus tissues, and shows that BnaWRKY10-mediated BnaCKX2 expression is essential for seed size regulation, providing promising targets for oil crop improvement. [ABSTRACT FROM AUTHOR]

Summary: Cytokinins (CKs) are important plant hormones that regulate a variety of biological processes implicated in plant development and stress responses. Here, we summarize the most recent advances in discovering and characterizing the membrane transporters involved in long‐ and short‐distance translocation of CKs and their significance in CK signal activity. We highlight the discovery of PUP7 and PUP21 tonoplast‐localized transporters and propose potential mechanisms for CK subcellular homeostasis. Finally, we discuss the importance of subcellular hormone transport in light of the localization of histidine kinase receptors of CKs at the endoplasmic reticulum and plasma membrane. [ABSTRACT FROM AUTHOR]

In order to facilitate studies on biological function of PUP family genes in Gossypium hirsutum, and provide candidate genes for subsequent studies on the function of PUP genes in stress resistance, in this study, 31 PUP genes were identified in Gossypium hirsutum(TM-1) genome using bioinformatics, and could be classified into 3 subfamilies according to polygenetic analysis. The results of chromosome location and gene replication analysis showed that 31 GhPUP genes were distributed on 19 chromosomes, and all PUP genes were generated by gene replication events, and the duplication type was fragment duplication. Gene structure analysis indicated that most PUP genes had only one intron, a few had two or three introns, and a few had no introns. Conserved domain analysis showed that both commonality and specificity existed between PUP proteins in different subfamilies. Cis-acting elements analysis showed that there were 18 elements in the GhPUP genes promoter region, which were classified into three categories: hormone response, stress/physical response, and plant growth and development related elements. At the same time, combined with evolutionary analysis and transcriptome data, PUP genes involved in stress response in Gossypium hirsutum were screened. [ABSTRACT FROM AUTHOR]

Copyright of Revista Colombiana de Ciencias Hortícolas is the property of Revista Colombiana de Ciencias Horticolas 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.)

Acmella ciliata Kunth (Cass.), a medicinally important plant in the family Asteraceae, has high commercial value because of its traditional phytomedicinal uses. The plant contains many phytochemicals like alkyl amides, alkaloids, tannins, saponins and flavonoids accountable for most of its pharmacological applications. The study presented here reports the callus culture and somatic embryogenesis of this plant thereby raising a novel system for the subsequent production of the Nalkyl amide 'spilanthol', the valuable secondary metabolite presents in it. Murashige and Skoog (MS) medium supplemented with auxins either alone or in combination with cytokinins were used for the induction and maturation of somatic embryos. MS medium supplemented with 2,4-D (0.5, 1.0 and 2.0 mg.L-1) produced black friable callus whereas, 1.0 mg.L-1 NAA in combination with 0.5 mg.L-1 BA induced white, slightly purple coloured friable callus which on further subculture to fresh medium induced somatic embryos that germinated into plantlets upon transfer to MS basal medium. The mode of regeneration via somatic embryogenesis was confirmed by histological analysis through free-hand sectioning and stereomicroscopic observation. The plantlets raised through somatic embryogenesis after a short hardening period, were found to acclimatise in the field at 83.33% efficiency and exhibited genetic uniformity with 96.6% similarity in the ISSR analysis. HPLC analysis of in vitro raised embryogenic callus showed 239.512 µg.g-1 spilanthol content which was comparatively higher than the mother plants (92.19 µg.g-1). The bioproduction of the N-alkylamide 'spilanthol' through embryogenic callus can be extended for the scale-up production of this bioactive compound using bioreactor technology for the formulation of phytodrugs. [ABSTRACT FROM AUTHOR]

Plants, unlike animals, possess a unique developmental plasticity, that allows them to adapt to changing environmental conditions. A fundamental aspect of this plasticity is their ability to undergo postembryonic de novo organogenesis. This requires the presence of regulators that trigger and mediate specific spatiotemporal changes in developmental programs. The phytohormone cytokinin has been known as a principal regulator of plant development for more than six decades. In de novo shoot organogenesis and in vitro shoot regeneration, cytokinins are the prime candidates for the signal that determines shoot identity. Both processes of de novo shoot apical meristem development are accompanied by changes in gene expression, cell fate reprogramming, and the switching-on of the shoot-specific homeodomain regulator, WUSCHEL. Current understanding about the role of cytokinins in the shoot regeneration will be discussed. [ABSTRACT FROM AUTHOR]

The present study investigated the interaction between reduced glutathione (GSH) and nitric oxide (NO) in enhancing the cold tolerance of cucumber seedlings. In this study, cold-sensitive 'Jinyan No. 4' cucumber seedlings were used as test materials. Four different treatments, including CK: distilled water (control), DS: distilled water + 200 μmol L−1 sodium nitroprusside (SNP), BS:1 mmol L−1 buthionine sulfoximine (BSO) + SNP, and SG: 200 μmol L−1 SNP + 5 mmol L−1 GSH were used to pretreat cucumber leaves. Pretreated cucumber seedling leaves were used for the analysis after 24 h and 48 h under low temperature (10 °C day/6 °C night). The results showed that compared with the control, DS and SG treatments could maintain lower K-step (48 h) and L-step (48 h) and higher P-step on the OJIP transient curve. The application of DS and SG also increased the values of maximal redox capacity of photosystem I (PSI) (∆I/Io), the primary photochemical efficiency (Fv/Fo), the maximum photochemical efficiency (Fv/Fm), the photosynthetic performance index (PIABS) (48 h), quantum yield for reducing the terminal electron acceptor on the acceptor side of PS I (φRo), the phenomenological energy fluxes per excited cross section (ABS/CSm, TRo/CSm, and ETo/CSm), and the density of per reaction center (RC/CSm), while decreasing some others like the relative variable fluorescence at J-step (VJ) (48 h), the quantum ratio of thermal dissipation (Fo/Fm), the dissipated energy flux per CS (DIo/CSm), and the specific energy fluxes per reaction center (DIo/RC), with the highest effect being observed in SG treatment. Furthermore, DS and SG treatments were observed a low level of hydrogen peroxide and superoxide, the enhancement of proline content, and some enzyme activities (AsA-GSH cycle), and the combined effect of SNP and GSH is more prominent than the single effect of SNP. In addition, BSO (GSH synthase inhibitor) can abolish or reverse the effect of SNP. Our results suggest that GSH may act downstream of NO to improve cold tolerance of cucumber seedlings under low-temperature stress, and more interestingly, NO and GSH play a synergistic role in mitigating the adverse effects of low-temperature stress. [ABSTRACT FROM AUTHOR]

A protocol for the cultivation of Larix sibirica Ledeb. by somatic embryogenesis was developed (RF Patent No. 2456344, 2012). The L. sibirica collection consisted of 22 actively proliferating cell lines (CLs) obtained from immature zygotic embryos. The age of CLs ranged from 1 to 14 years. CLs differed in their growth intensity, embryonic productivity, hormonal balance, and genetic stability, as well as in their regenerative ability. In most proliferating CLs, the formation of globular somatic embryos continued for 2–4 years. Here, a number of CLs actively proliferated for 9–14 years or more. The formation of embryogenic cultures in L. sibirica is associated with the content of phytohormones and their localization in embryo cells. The cytogenetic studies revealed the genetic stability of young CLs (up to 1 year), in which the karyotype consisted of the diploid number of chromosomes (2n = 24). Genomic mutations were observed in the long-term proliferation of CLs. Individual CLs can maintain cytogenetic stability for many years; such CLs can successfully be used to preserve germplasm, obtain planting material, and for plantation reforestation. [ABSTRACT FROM AUTHOR]

A promising carrier for the development of polymer systems with controlled release of biologically active compounds is the aminopolysaccharide chitosan. In the present work, we studied the possibility of using chitosan films as a matrix for the N6-benzyladenine (BA), which is the natural cytokinin widely used in tissue culture. The aim of this work was to develop biopolymer carriers containing phytohormones cytokinins that provide its controlled release. As a result of the work, a number of biopolymer carriers containing BA were obtained, and the kinetics of moisture absorption of the resulting complexes and the kinetics of their release of cytokinins were studied. It has been shown that the use of a polymer carrier based on chitosan is a convenient matrix for achieving a prolonged biological effect from cytokinins. The obtained results will make it possible to purposefully design materials with an optimal delivery rate of cytokinins for a biological object. [ABSTRACT FROM AUTHOR]

Soil drought, which is one of the most threatening abiotic plant stressors, negatively impacts plant growth and yields. Plant phytohormones play a key role in the formation of plant responses to stress. We investigated the effect of moderate soil drought, created in controlled laboratory conditions on plant growth and peculiarities of endogenous abscisic (ABA), indole-3-acetic (IAA), gibberellic (GA3) and salicylic (SA) acids and cytokinins (CKs) accumulation in organs of two closely related wheat species: Triticum aestivum and T. spelta. We demonstrated that following the cessation of watering (within four days), shoots and roots of 18-day-old plants of both species accumulated ABA and SA, while the level of GA3 and IAA decreased. Pool of CKs significantly increased in roots and decreased in shoots. On day 21 following recovery, an increase in ABA content occurred in wheat shoots and roots and spelt shoots. IAA level increased in both species, but not to the levels measured in control plants. The highest level of GA3 was present in wheat roots. While the content of SA in wheat was at control level, spelt SA levels significantly exceeded the controls. There were complex changes in CKs pool, the nature of which depended on the species and plant organ. We propose that specific alterations in the nature of accumulation, localization, and balance between certain classes of phytohormones in wheat and spelt organs under the action of moderate soil drought are one of the main factors in systemic response to stress and the formation of an adaptation strategy. [ABSTRACT FROM AUTHOR]

With global climate warming, recurring extreme heat and high temperatures irreversibly damage plants. Raspberries, known for their nutritional and medicinal value, are in high demand worldwide. Thus, it is important to study how hightemperature stress (HTS) affects raspberries. The physiological and biochemical responses and molecular genetic mechanisms of raspberry leaves to different HTS treatments were investigated: mild high temperature at 35°C (HT35), severe high temperature at 40°C (HT40), and the control at room temperature of 25°C (CK). The physiological results suggested that leaves in both the 35°C and 40°C treatments showed maximum relative conductivity at 4 d of stress, increasing by 28.54% and 43.36%, respectively, compared to CK. Throughout the stress period (0-4 d), malondialdehyde (MDA) and soluble protein contents of raspberry leaves increased under HT35 and HT40 treatments, while soluble sugar content first decreased and then increased. Catalase (CAT) activity increased, superoxide dismutase (SOD) activity first increased and then decreased, and peroxidase (POD) activity gradually decreased. Photosynthetic and fluorescence responses of raspberry leaves showed the most severe impairment after 4 d of stress. Transcriptomics results revealed significant alterations in 42 HSP family genes, two SOD-related differentially expressed genes (DEGs), 25 POD-related DEGs, three CAT-related DEGs, and 38 photosynthesis-related DEGs under HTS. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis showed that these DEGs were mainly enriched in photosynthesis-antenna proteins, pentose and glucuronide interconversion, phenylpropane biosynthesis, and indole alkaloid biosynthesis. HTS induced excessive ROS accumulation in raspberry leaves, causing oxidative damage in plant cells and subsequently reducing photosynthesis in raspberry leaves. This reduction in photosynthesis, in turn, affects photosynthetic carbon fixation and starch and sucrose metabolism, which, combined with phenol propane biosynthesis, mitigates the HTSinduced damage. [ABSTRACT FROM AUTHOR]

Soil microorganisms play important roles in promoting soil ecosystem restoration, but much of the current research has been limited to changes in microbial community structure in general, and little is known regarding the soil physicochemical property and microbial community structure. In this study, four organic fertilizers were first prepared based on tea oil camellia shell (TOCS). Our findings indicate that the application of BOFvo increased both total pore volume and BET surface area of the rhizosphere soils, as well there was a remarkable enhancement in total organic matter (TOM), total nitrogen (TN), available nitrogen (AN), total phosphorus (TP), total potassium (TK), and available potassium (AK) contents of the rhizosphere soils. Meanwhile, in comparison to the CK and CF groups, the utilization of BOFvo led to a substantial increase in both average yield and fruiting rate per plant at maturity, as well resulted in a significant increase in TN and TP contents of tea oil camellia leaves. Furthermore, our findings suggest that the application of TOCS-based organic fertilizers significantly enhances the microbial diversity in the rhizosphere soils with Proteobacteria and Ascomycota being the dominant bacterial and fungal phyla, respectively, and Rhodanobacter and Fusarium being the dominant bacterial and fungal genus, respectively. Redundancy analysis (RDA) indicates that the physicochemical characteristics of TOCS-based organic fertilizers had a significant impact on the composition and distribution of microbial communities in the rhizosphere soils. This study will facilitate the promotion and application of TOCS-based organic fertilizers, thereby establishing a foundation for the reuse of tea oil camellia waste resources. [ABSTRACT FROM AUTHOR]

The process of apical dominance by which the apical bud/shoot tip of the plant inhibits the outgrowth of axillary buds located below has been studied for more than a century. Different approaches were used over time, with first the physiology era, the genetic era, and then the multidisciplinary era. During the physiology era, auxin was thought of as the master regulator of apical dominance acting indirectly to inhibit bud outgrowth via unknown secondary messenger(s). Potential candidates were cytokinin (CK) and abscisic acid (ABA). The genetic era with the screening of shoot branching mutants in different species revealed the existence of a novel carotenoid-derived branching inhibitor and led to the significant discovery of strigolactones (SLs) as a novel class of plant hormones. The re-discovery of the major role of sugars in apical dominance emerged from modern physiology experiments and involves ongoing work with genetic material affected in sugar signalling. As crops and natural selection rely on the emergent properties of networks such as this branching network, future work should explore the whole network, the details of which are critical but not individually sufficient to solve the 'wicked problems' of sustainable food supply and climate change. [ABSTRACT FROM AUTHOR]

Cytokinins are members of a group of phytohormones involved in various growth and developmental processes in plants. Isopentenyl transferase (IPT) is the rate-limiting enzyme in catalyzing the biosynthesis of cytokinins. In this study, to understand the role of IPT family in cold resistance, 78 IPT candidates were identified and characterized in nine Rosaceae genomes. The expansion of IPT families in the Rosaceae primarily occurred through segmental duplication rather than tandem duplication. In general, purifying selection controlled the evolution of IPT families in the Rosaceae, with IPT3 and IPT5 homologs as the primary drivers of evolution. Cis-elements, which are involved in the responses to many environmental stresses or phytohormone signals, were identified in the promoters of MdIPT members. This was consistent with the trends of expression of the MdIPT genes in apple (Malus domestica) calli. MdIPT5b was also found to exhibit multiple responses to phytohormones and stress signals. The ectopic expression of MdIPT5b resulted in an increase in cold resistance in transformed apple calli and tomato (Solanum lycopersicum) plantlets. The redox balance was partially stabilized through the accumulation of proline under cold stress. However, the ascorbateeglutathione cycle cannot be stabilized in the cold. All physiological and biochemical assays are preformed in spectrophotometer. These results showed that regulating the expression of IPT genes for moderate cytokinin improvement could enhance the accumulation of proline to stabilize the osmotic and redox balances to improve resistance to cold stress. [ABSTRACT FROM AUTHOR]

Corolla opening is essential for the propagation of unisexual flowering plants, meanwhile commodity fruits with opening corolla have higher commodity value in cucumber fresh food market. Until now, there is little research on the mechanism of corolla opening in cucumber. In a previous paper, we identified a unique cucumber (Cucumis sativus) line ('6457') that possesses super ovaries and shows delayed corolla opening when nutrient supplies are abundant. We also previously showed that the expression of CsIPT1b (isopentenyl transferase) and CsUGT85A2 (cytokinin glycosyltransferase) is correlated with the delayed opening of the female corolla. Here, we investigated the mechanism of delayed female corolla opening in cucumber by conducting transgenic experiments, hormone assays, and yeast one-hybrid assays. CsIPT1b and CsUGT85A2 positively and negatively regulated delayed female corolla opening, respectively. In CsIPT1b-overexpressing plants and CsUGT85A2 knockout plants, the content of the trans-zeatin riboside, trans-zeatin, and N6-isopentenyladenosine was increased. Overall, our findings indicate that CsIPT1b and CsUGT85A2 were important regulators of the timing of female corolla opening. These genes could thus be targets to cucumber molecular breeding of fruit with flowers remaining on the tip. [ABSTRACT FROM AUTHOR]

Vigna unguiculata (L.) Walp. (subsp. sesquipedalis) is a legume species, widely cultivated in the tropics. The seeds of the plant show orthodox behavior during development with an initial influx of water from the maternal tissues during early embryogeny but declined in subsequent stages of embryo development. The seed acquire desiccation tolerance during embryo drying stage and remains viable for months. However the fully mature seed germinates within two days of hydration. PGRs play an important role in all these processes, since the levels of various hormones change dramatically during the developmental sequence. Seven classes of major PGRs were simultaneously assayed using LC-MS/MS in order to understand the hormonal dynamics and to establish the possible interactions during the orthodox cowpea seed development and germination. There was a differential accumulation of IAA, GA4, tZ, tZR, JA and cisJ in the early embryogeny stage. These PGRs were down regulated in subsequent stages of embryo development. tZ, GA4 and JA were up-regulated upon water induction during germination. ABA was up-regulated in response to a drop in moisture content showing a peak in the mid-embryogeny and down regulated in all other stages including germination. GA/ABA antagonism was observed during the germination in cowpea. SA was found in exceptionally higher level in all stages of seed development and germination. 24-epiBL was detected in significant levels in all stages of development with two peaking in early and late embryogeny. BA, IBA, metJ, GA3, GA7 and ACC were found in insignificant levels in the seeds. Multiple correlation studies showed a strong positive correlation of IAA and JA with cytokinins (tZ and tZR) indicating possible cross-talk between these PGRs. [ABSTRACT FROM AUTHOR]

Plants have evolved signaling mechanisms such as the multi-step phosphorelay (MSP) to respond to different internal and external stimuli. MSP responses often result in gene transcription regulation that is modulated through transcription factors such as B-type Arabidopsis response regulator (ARR) proteins. Among these proteins, ARR2 is a key component that is expressed ubiquitously and is involved in many aspects of plant development. Although it has been noted that B-type ARRs bind to their cognate genes through a DNA-binding domain termed the GARP domain, little is known about the structure and function of this type of DNA-binding domain; thus, how ARRs bind to DNA at a structural level is still poorly understood. In order to understand how the MSP functions in planta, it is crucial to unravel both the kinetics as well as the structural identity of the components involved in such interactions. For this reason, this work focusses on resolving how the GARP domain of ARR2 (GARP2) binds to the promoter region of ARR5, one of its native target genes in cytokinin signaling. We have established that GARP2 specifically binds to the ARR5 promoter with three different bi-molecular interaction systems—qDPI-ELISA, FCS, and MST—and we also determined the KD of this interaction. In addition, structural modeling of the GARP2 domain confirms that GARP2 entails a HTH motif, and that protein–DNA interaction most likely occurs via the α3-helix and the N-terminal arm of this domain since mutations in this region hinder ARR2's ability to activate transcription. [ABSTRACT FROM AUTHOR]

Tea plants are highly susceptible to the adverse effects of a high-temperature climate, which can cause reduced yield and quality and even lead to plant death in severe cases. Therefore, reducing the damage caused by high-temperature stress and maintaining the photosynthetic capacity of tea plants is a critical technical challenge. In this study, we investigated the impact of small oligopeptides (small peptides) and surfactants on the high-temperature-stress tolerance of tea plants. Our findings demonstrated that the use of small peptides and surfactants enhances the antioxidant capacity of tea plants and protects their photosynthetic system. They also induce an increase in gibberellin (GA) content and a decrease in jasmonic acid (JA), strigolactone (SL), auxin (IAA), and cytokinin (CTK) content. At the same time, small peptides regulate the metabolic pathways of diterpenoid biosynthesis. Additionally, small peptides and surfactants induce an increase in L-Carnosine and N-Glycyl-L-Leucine content and a decrease in (5-L-Glutamyl)-L-Amino Acid content, and they also regulate the metabolic pathways of Beta-Alanine metabolism, Thiamine metabolism, and Glutathione metabolism. In summary, small peptides and surfactants enhance the ability of tea plants to resist high-temperature stress. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office 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.)

Carbohydrates, particularly sucrose in the sugarcane crop, are of much value and are required in a number of metabolic activities. Sucrose production and accumulation along with sucrose processing and mechanism in sugarcane have been elaborately studied. Enzymes and hormones have an important role and function in this perspective. The four metabolizing sugar enzymes (sucrose phosphate synthase, sucrose synthase, sucrose phosphate phosphatase, invertase) and eight phytohormones (auxin, abscisic acid, cytokinin, salicylic acid, gibberellic acid, ethylene, brassinosteroids, and jasmonic acid) play a pivotal crucial role in sucrose biosynthesis and accumulation in sugarcane. Their interaction with sugar transporters at certain checkpoints is even equally important. The allocation of sugars requires a source-sink dynamics wherein the importance of sucrose loading and unloading in phloem tissue involves the use of different sugar transporters. These sugar transporters have influenced the sugarcane survival capability at the severe, moderate and mild impact of abiotic (like drought) and biotic (like diseases) stresses. Their interaction with enzymes and phytohormones has contributed to the tolerance potential of sugarcane. In this review, we focus on the sucrose production and storage process and the involvement of phytohormones in sugarcane under normal and abiotic stress conditions. Furthermore, the various sugar metabolizing enzymes and different sugar transporters have been identified in sugarcane and their significance has also been described in brief. [ABSTRACT FROM AUTHOR]

An in vitro regeneration method with functional morpho-structural and physiological traits has been optimized for Aloe vera L. in the present study. Among the various types and treatments of cytokinins [6-benzylaminopurine, BAP; 6-(3-hydroxybenzylamino) purine, mT (meta-topolin), and 1-phenyl-3-(1,2,3-thiadiazol-5-yl) urea, TDZ] tested for shoot induction, the best bud break response (100%) occurred on the Murashige and Skoog (MS) medium containing 1.0 mg L−1 mT with the development of 5.0 shoots with 3.3 cm average length. Liquid MS medium containing a standardized combination of 0.5 mg L−1 mT with 0.25 mg L−1 α-naphthalene acetic acid (NAA) triggered proliferation of shoots, and maximum 42 shoots with 5.6 cm average length were obtained after 3rd subculture. Meta-topolin and NAA-derived shoots cultured on half strength MS medium containing 1.0 mg L−1 Indole-3-butyric acid (IBA) resulted in maximum rhizogenesis than BAP + NAA and TDZ + NAA-derived shoots. Meta-topolin and NAA combination improved photo-pigments, net rate of photosynthesis, and morpho-anatomy of leaves as compared with other treatments. The rate of photosynthesis, transpiration, and field survival was significantly affected by the types and concentrations of cytokinins used during plantlet development. The present findings unraveled the potential of meta-topolin to alleviate in vitro induced morpho-structural and physiological anomalies and improved survival of micropropagated plantlets of A. vera. [ABSTRACT FROM AUTHOR]

Natural extracts of Hypericum perforatum L. are widely used in the pharmaceutical industry due to their antiviral, antioxidant, antibacterial, antidiabetic, and antidepressant activities. Plant biotechnological methods are gaining more attention as efficient and biosustainable approaches for the production of high value compounds by using plant callus cultures in vitro. The aim of this research was to evaluate the influence of phytohormones on the formation of Hypericum perforatum L. callus culture, to explore antioxidant and antibacterial activities, and to determine the amounts of phytochemicals in the analyzed extracts. Callus cultures were induced on Murashige and Skoog basal medium supplemented with phytohormones (auxins, cytokinins, and salicylic acid), and containing newly synthesized compound N-(1,3-dioxoisoindolin-2-yl)-3-((4-methoxyphenyl)amino)propanamide. The antioxidant activities of callus cultures were evaluated using DPPH and FRAP assays and the enzyme antioxidants (superoxide dismutase, catalase, and ascorbate peroxidase) were evaluated. The antibacterial activity of plant extracts was screened against Escherichia coli and Bacillus subtilis bacteria by the diffusion agar method. There was a significant positive correlation between total phenolic content and high antioxidant efficiency in Hypericum perforatum L. callus cultures, which were formed on Murashige and Skoog medium supplemented with auxin, cytokinin, and salicylic acid (100 µM). Our results have demonstrated that callus cultures generated on MS medium supplemented with N-(1,3-dioxoisoindolin-2-yl)-3-((4-methoxyphenyl)amino)propanamide and cytokinin BAP (0.5 mg L−1) exhibited improved antioxidant activities for the first time. [ABSTRACT FROM AUTHOR]

Phytohormones exhibit a wide range of chemical structures, though they primarily originate from three key metabolic precursors: amino acids, isoprenoids, and lipids. Specific amino acids, such as tryptophan, methionine, phenylalanine, and arginine, contribute to the production of various phytohormones, including auxins, melatonin, ethylene, salicylic acid, and polyamines. Isoprenoids are the foundation of five phytohormone categories: cytokinins, brassinosteroids, gibberellins, abscisic acid, and strigolactones. Furthermore, lipids, i.e., α-linolenic acid, function as a precursor for jasmonic acid. The biosynthesis routes of these different plant hormones are intricately complex. Understanding of these processes can greatly enhance our knowledge of how these hormones regulate plant growth, development, and physiology. This review focuses on detailing the biosynthetic pathways of phytohormones. [ABSTRACT FROM AUTHOR]

The aim of this study was to clarify the effects of thinning on the chemical composition of fine roots of different orders in Pinus massoniana plantations. We investigated the chemical composition of P. massoniana fine roots of different orders under different thinning intensities [i.e., light intensity thinning (LIT, 25%); moderate intensity thinning (MIT, 45%); heavy intensity thinning (HIT, 65%)] and non-thinned control (CK, 0%) in a 36-year-old P. massoniana plantation in Lishui District, Nanjing. The fine roots were divided into 1st-5th root orders by using the root order classification method. The variations in the chemical composition of fine roots were compared under different thinning intensities, while the relationship between the chemical composition of fine roots and the soil′s physical and chemical properties was analyzed. The results showed that with the increase in root order, the fine root total nitrogen, total phosphorus, and lignin content decreased; the fine root total carbon and cellulose content increased; and fine root total potassium content had no clear change. Compared with the control plot, light-thinning intensity significantly reduced the total nitrogen content of the 2nd-order roots, whereas thinning intensities significantly increased the total nitrogen content of 1st-4th-order roots. Thinning intensities significantly increased the total phosphorus content of the 1st and 3rd-4th-order roots. Light thinning intensity significantly increased the total potassium content of 1st-2nd and 4th-order roots, whereas light and heavy thinning intensities significantly increased the total potassium content of 3rd-order roots. Thinning increased the total carbon content of 1st-2nd-order roots significantly. It also increased the lignin content of 1st and 3rd-order roots significantly, whereas moderate and heavy thinning increased the lignin content of 1st-5th-order roots and 1st-4th-order roots, respectively. Thinning increased the cellulose content of the 1st-2nd-order roots significantly. Correlation analysis showed that the chemical contents of fine roots of different root orders were significantly related to soil pH, soil total nitrogen, ammonium nitrogen, nitrate nitrogen, total phosphorus, and available phosphorus content. We concluded that thinning could increase the fine root contents, nutrient concentrations, and structural carbohydrates in different orders of fine roots of P. massoniana plantations by changing the soil pH and nutrient contents. [ABSTRACT FROM AUTHOR]

In contrast to inorganic nitrogen (N) assimilation, the role of organic N forms, such as proteins and peptides, as sources of N and their impact on plant metabolism remains unclear. Simultaneously, organic biostimulants are used as priming agents to improve plant defense response. Here, we analysed the metabolic response of tobacco plants grown in vitro with casein hydrolysate or protein. As the sole source of N, casein hydrolysate enabled tobacco growth, while protein casein was used only to a limited extent. Free amino acids were detected in the roots of tobacco plants grown with protein casein but not in the plants grown with no source of N. Combining hydrolysate with inorganic N had beneficial effects on growth, root N uptake and protein content. The metabolism of casein‐supplemented plants shifted to aromatic (Trp), branched‐chain (Ile, Leu, Val) and basic (Arg, His, Lys) amino acids, suggesting their preferential uptake and/or alterations in their metabolic pathways. Complementarily, proteomic analysis of tobacco roots identified peptidase C1A and peptidase S10 families as potential key players in casein degradation and response to N starvation. Moreover, amidases were significantly upregulated, most likely for their role in ammonia release and impact on auxin synthesis. In phytohormonal analysis, both forms of casein influenced phenylacetic acid and cytokinin contents, suggesting a root system response to scarce N availability. In turn, metabolomics highlighted the stimulation of some plant defense mechanisms under such growth conditions, that is, the high concentrations of secondary metabolites (e.g., ferulic acid) and heat shock proteins. [ABSTRACT FROM AUTHOR]

Melatonin is a stress‐related hormone that plays a critical role in triggering the plant defence system and regulating secondary metabolism when plants are exposed to stress. To explore the potential roles of melatonin in response to Ultraviolet‐B (UV‐B) radiation, we examined the effects of exogenous melatonin on rosemary in vitro shoots under UV‐B stress. The application of melatonin (50 μM) alleviated the adverse effects of UV‐B stress on the biomass, photosynthetic pigment contents, and membrane lipids of the rosemary in vitro shoots. Melatonin significantly increased superoxide dismutase (1.15.1.1, SOD), peroxidase (1.11.1.7, POD), and catalase (1.11.1.6, CAT) activities by 62%, 99%, and 53%, respectively. The contents of total phenols, rosmarinic acid, and carnosic acid increased under UV‐B stress, and they further increased by the melatonin treatment by 41%, 68%, and 67%, respectively, compared with the control group. Under UV‐B stress, the increased total phenol content in melatonin‐pretreated plants could be attributed to the activation of phenylalanine ammonia‐lyase (4.3.1.5, PAL) and tyrosine aminotransferase (2.6.1.5, TAT). In addition, melatonin enhanced the antioxidant and antibacterial activities of the rosemary in vitro shoots under UV‐B stress. These results suggest that melatonin can alleviate the damage caused by UV‐B stress and also enhance the secondary metabolism and bioactivity of rosemary in vitro shoots. [ABSTRACT FROM AUTHOR]

This study was conducted during the period from 23rd September 2021 to 1st May 2022 in Horticulture stations / Akre / Iraqi Kurdistan region, amid to schedule the flower production of Chrysanthemum (Dendrathema grandiflora Tzvelev), by use the supplemental light with (Natural (unlit), 1.5-month, 3-month), BA with 0, 200 and 400 mg.l-1 and two cultivars Avalon (pink) and Flirt (red). The study was performed by use Random Complete Block Design (RCBD). The best results include, use 3-monthof supplemental light significantly increased the number of day to flower bud appearance and the number of days to flower anthesis to 143.36 and 201.10 day for the two cultivars Avalon and Flirt respectively compared with 1.5 month which need 119.61, 175.02 day and clontrol which need 49.28, 78.31 day for the two cultivars respectively, this mean that 3-month delay the flower production by 122.79 day than control. Plant height, flower grade and Plant growth index also increased significantly with increased the supplemental light to 1.5 and 3-month compared with control. Sprayed Chrysanthemum with BA increased significantly the day to flower bud appearance, vase life and flower grade compared with control. The Flirt (red) cultivar significantly superior than Avalon (pink) in day to flower bud appearance, day to flowering anthesis, plant high and flower grade. [ABSTRACT FROM AUTHOR]

Waterlogging is a major abiotic stress that plants encounter as a result of climate change impacts. Peach is very sensitive to hypoxia during waterlogging, which causes poor tree vigor and huge economic losses. The molecular mechanism underlying the peach response to waterlogging and reoxygenation remains unclear. Here, the physiological and molecular responses of 3-week-old peach seedlings under waterlogged and recovery conditions were comprehensively analyzed. As a result, waterlogging significantly reduced plant height and biomass with inhibition of root growth when compared with control and reoxygenation. Similar results were observed for photosynthetic activities and gaseous exchange parameters. Waterlogging increased lipid peroxidation, hydrogen peroxide, proline, glutamic acid and glutathione contents, while superoxide dismutase, peroxidases and catalase activities were decreased. The glucose and fructose contents were accumulated, contrary to sucrose which was reduced remarkably throughout the stress periods. The level of endogenous indole acetic acid (IAA) was increased in waterlogging but decreased after reoxygenation. However, the change trends of jasmonic acid (JA), cytokinins and abscisic acid (ABA) levels were opposite to IAA. In transcriptomic analysis, there were 13,343 differentially expressed genes (DEGs) with higher and 16,112 genes with lower expression. These DEGs were greatly enriched in carbohydrate metabolism, anaerobic fermentation, glutathione metabolism and IAA hormone biosynthesis under waterlogging, while they were significantly enriched in photosynthesis, reactive oxygen species scavenging, ABA and JA hormones biosynthesis in reoxygenation. Moreover, several genes related to stress response, carbohydrate metabolism and hormones biosynthesis were significantly changed in waterlogging and reoxygenation, which indicated unbalanced amino acid, carbon and fatty acid pools in peach roots. Taken together, these results suggest that glutathione, primary sugars and hormone biosynthesis and signaling might play key roles in plant response to waterlogging. Our work provides a comprehensive understanding of gene regulatory networks and metabolites in waterlogging stress and its recuperation, which will facilitate peach waterlogging control. [ABSTRACT FROM AUTHOR]

In the quest for novel medications, researchers have kept on studying nature to unearth beneficial plant species with medicinal qualities that may cure various diseases and disorders. These medicinal plants produce different bioactive secondary metabolites with immense therapeutic importance. One such valuable secondary metabolite, reserpine (C33H40N2O9), has been used for centuries to cure various ailments like hypertension, cardiovascular diseases, neurological diseases, breast cancer, and human promyelocytic leukaemia. Rauvolfia spp. (family Apocynaceae) is an essential reservoir of this reserpine. The current review thoroughly covers different non-conventional or in vitro–mediated biotechnological methods adopted for pilot-scale as well as large-scale production of reserpine from Rauvolfia spp., including techniques like multiple shoot culture, callus culture, cell suspension culture, precursor feeding, elicitation, synthetic seed production, scale-up via bioreactor, and hairy root culture. This review further analyses the unexplored and cutting-edge biotechnological tools and techniques to alleviate reserpine production. Key points: • Reserpine, a vital indole alkaloid from Rauvolfia spp., has been used for centuries to cure several ailments. • Overview of biosynthetic pathways and biotechnological applications for enhanced production of reserpine. • Probes the research gaps and proposes novel alternative techniques to meet the pharmaceutical industry's need for reserpine while reducing the over-exploitation of natural resources. [ABSTRACT FROM AUTHOR]

Plant tissue culture and novel breeding techniques such as genome editing in the economically important crop Arachis hypogaea constitute potential for genetic improvement. Therefore, in this study, high-frequency in vitro regeneration via formation of adventitious shoots was described for different A. hypogaea lines. The leaflets of the primary leaves of 5-day-old seedlings were cultured for 16 weeks on Murashige and Skoog's medium supplemented with equimolar concentrations (22.19 µM) of the cytokinins 6-benzylaminopurine (BAP); thidiazuron (TDZ); zeatin (Zea) or meta-topolin (MT), which was reduced to 7.40 µM after eight weeks plus 2.3 µM kinetin. Highest shoot regeneration percentages of 89.1% and 81.3% for BAP and TDZ containing media, respectively, were achieved in the line 'Jimmy's pride' with the maximum shoot number obtained on BAP. The regeneration percentages for three further lines were lower than 50%. Furthermore, the effect of different light qualities, applied using LEDs, and compared to fluorescent lamps was investigated. Shoot regeneration percentages did not improve significantly under the different LEDs, instead a pronounced effect on the regeneration efficiency of the culture temperature was observed which differed among the light treatments. However, fluorescent lamps can be replaced by red or blue LEDs without negative effects on shoot regeneration. [ABSTRACT FROM AUTHOR]

Barley is the major raw material for the malting and brewing industries. Seed germination is a fundamental process for malting and is affected by physical and chemical factors, especially plant hormones. It is well recognized that the phytohormones gibberellic acid (GA) and abscisic acid (ABA) are the primary hormones that antagonistically regulate barley germination. Other plant hormones, including auxin (IAA), ethylene (ET), brassinosteroid (BR), jasmonic acid (JA), salicylic acid (SA), cytokinins (CTKs), and strigolactone (SLs) also regulate seed germination by mediating the ABA/GA balance. In this study, the effects of eight hormones added during barley germination were investigated. An efficient design of the experimental method was employed to assess the effect of eight factors (α-amylase, β-amylase, limit dextrinase, β-glucanase, wort sugar profile, FAN, and β-glucan content) on epicotyl and root elongation. Almost all studied phytohormones played a significant role on barley epicotyl elongation. GA, ET, BA (benzylaminopurine), and zeatin (ZEA) exerted an increased effect, while ABA, SA, and BR showed a decreased effect for α-amylase, β-amylase, limit dextrinase, and β-glucanase activity. Results showed that in addition to GA and ABA, that SA, ET, BR, BA, ZEA, and JA also had significant effects on malt quality. The balance between these phytohormones is vital to the malting quality of barley. Future applications of these results could improve current recognition about the effects of phytohormones on malting and provide concrete ideas for enhancing malt quality. [ABSTRACT FROM AUTHOR]

Anthropogenic activities have drastically increased nitrogen (N) deposition, resulting in increased N availability. The continuous increase of N availability may exacerbate phosphorus (P) deficiency, which would limit forest productivity in subtropical forests. Effects of long-time N and N + P additions on SOC turnover in subtropical forests is therefore crucial for understanding the global carbon (C) cycle. The argument of whether N and N + P addition accelerates or slows SOC turnover has been under debate, particularly in P-limited subtropical forests. This study mainly aims to confirm this argument. A ten-year field experiment was conducted in a subtropical evergreen broad-leaved forest in southern Anhui, China. We measured the soil δ13CSOC contents and physicochemical properties under N (100 kg N·ha−1·a−1), N + P (100 kg N ha−1·a−1 + 50 kg P ha−1·a−1) additions, and the control (CK, no N and P additions). We also estimated the β value, which represents the soil organic carbon (SOC) turnover rate, from the slope of the regression between the log10-transformed SOC content and δ13CSOC in soil depth profiles. Our findings revealed that N addition significantly affected soil δ13CSOC compared to CK on both mid-slope and flat ridge sites. The β values responded differently to various treatments and sites. On the mid-slope, the β values did not show significant change with N and N + P additions. On the flat ridge, however, the β value decreased significantly in N and N + P additions, implying an increased SOC turnover rate. In addition, analysis of soil C–N–P stoichiometric ratios and physicochemical properties showed that N and N + P additions could affect β values by modifying soil nutrient content and composition. In general, our findings indicate that N and N + P additions could accelerate the SOC turnover in subtropical forest ecosystems, albeit with close dependence on site-specific factors. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Botanical Research is the property of Bulletin of Botanical Research Editorial Department 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.)

Attacks on plants by both viruses and their vectors is common in nature. Yet the dynamics of the plant-virus-vector tripartite system, in particular the effects of viral infection on plant-insect interactions, have only begun to emerge in the last decade. Viruses can modulate the interactions between insect vectors and plants via the jasmonate, salicylic acid and ethylene phytohormone pathways, resulting in changes in fitness and viral transmission capacity of their insect vectors. Virus infection of plants may also modulate other phytohormones, such as auxin, gibberellins, cytokinins, brassinosteroids and abscisic acid, with yet undefined consequences on plant-insect interactions. Moreover, virus infection in plants may incur changes to other plant traits, such as nutrition and secondary metabolites, that potentially contribute to virus-associated, phytohormone-mediated manipulation of plant-insect interactions. In this article, we review the research progress, discuss issues related to the complexity and variability of the viral modulation of plant interactions with insect vectors, and suggest future directions of research in this field.

Early root growth is critical for plant establishment and survival. We have identified a molecular pathway required for helical root tip movement known as circumnutation. Here, we report a multiscale investigation of the regulation and function of this phenomenon. We identify key cell signaling events comprising interaction of the ethylene, cytokinin, and auxin hormone signaling pathways. We identify the gene Oryza sativa histidine kinase-1 (HK1) as well as the auxin influx carrier gene OsAUX1 as essential regulators of this process in rice. Robophysical modeling and growth challenge experiments indicate circumnutation is critical for seedling establishment in rocky soil, consistent with the long-standing hypothesis that root circumnutation facilitates growth past obstacles. Thus, the integration of robotics, physics, and biology has elucidated the functional importance of root circumnutation and uncovered the molecular mechanisms underlying its regulation.

Lilies are bulbous flowers cherished for their aesthetic and medicinal value. Within the realm of lily cultivation, scale-cutting serves as a prevailing method for vegetative propagation, yielding diminutive bulbs termed bulblets at the base of scales. However, the burgeoning demand for lilies necessitates the optimization of propagation strategies to satisfy the surging requisites. This study centers on two synthetic cytokinin analogs, N-(2-chloro-4-pyridyl)-N'-phenylurea (CPPU) and 2-isopentenyladenine (2-iP), identified for their capacity to amplify bulblet formation within the Asiatic hybrid lily cultivar 'Matrix'. This dynamic process encompasses two pivotal phases: initiation and development. During bulblet initiation, the basal region of the maternal scale, subject to CPPU and 2-iP treatment, exhibited an elevation in the expression of cytokinin receptor genes (LaAHK2/3/4) and an augmented GA3/ZT ratio in comparison to the control, concomitant with a decrease in the IAA/ZT ratio. Moreover, CPPU and 2-iP treatments caused a notable upregulation of sucrose metabolism genes. During bulblet development stage, CPPU and 2-iP treatments invoked an augmentation in both the diameter and mass of the bulblets. The CPPU treatment accentuated the accumulation of GA3, while the 2-iP treatment effectively fostered the accrual of IAA. Additionally, both CPPU and 2-iP treatments expedited the pace of sucrose utilization and the accumulation of starch during bulblet development. This enhanced metabolic activity was conjoined by a substantial upregulation of genes linked to sucrose metabolism. Here, we underscore the proficiency of CPPU and 2-iP in elevating the formation of lily bulblets through their orchestrated impact on hormone levels and sucrose metabolism.

AbstractCork oak (Quercus suber L.) is one of the most important Mediterranean forest tree species, and the Maâmora forest-Morocco is considered to be the world largest cork oak stand. Clonal propagation of Quercus suber via somatic embryogenesis is an alternative to conventional tree propagation methods. However, complete maturation of somatic embryos is considered the major bottleneck for mass propagation of Quercus suber during somatic embryogenesis. This study focuses on influences of cytokinins on secondary somatic embryogenesis. Cytokinins showed a negative effect on the induction of secondary somatic embryogenesis. For the various concentrations tested, the number of secondary somatic embryos was significantly reduced except in the case with low dose of 2iP, which showed a slight increase. Abscisic acid (ABA) may be beneficial at low concentrations between 0.3 and 0.5 mg/l. The best number of secondary embryos was given at 0.5 mg/l ABA with an average number of 5 embryos from each primary embryo, which represents a slight increase below 10% compared to control medium. Also, we found that the number of responsive embryos presenting secondary somatic embryos based on their cotyledons decreased once adding ABA. Phenylurea derivatives TDZ and DPU do not promoted the process of secondary somatic embryogenesis. DPU showed no significant effect with a similar response to that of the control medium and TDZ showed an inhibitory effect. Gibberellic acid (GA3) partially blocked the process of somatic embryos multiplication, but promoted remarkably the germination of cotyledonary embryos without requesting a particular protocol. Our results provide a new insight into embryo development, establishing the basis for further research toward improvement of secondary somatic embryogenesis in Moroccan cork oak.

Phytohormones represent a group of secondary metabolites with different chemical structures, in which belong auxins, cytokinins, gibberellins, or brassinosteroids. In higher plants, they cover active roles in growth or defense function, while their potential benefits for human health protection were noted for some phytohormones and little explored for many others. In this study, we developed a target fishing strategy on fifty-three selected naturally occurring phytohormones covering different families towards proteins involved in key cellular functions related to human metabolism and health protection/disease. This in silico analysis strategy aims to screen the potential human health-driven bioactivity of more than fifty phytohormones through the analysis of their interactions with specific targets. From this analysis, twenty-eight human targets were recovered. Some targets e.g., the proteins mitochondrial glutamate dehydrogenase (GLUD1) or nerve growth factor (NGF) bound many phytohormones, highlighting their involvement in amino acid metabolism and/or in the maintenance or survival of neurons. Conversely, some phytohormones specifically interacted with some proteins, e.g., SPRY domain-containing SOCS box protein 2 (SPSB2) or Inosine-5′-monophosphate dehydrogenase 1 (IMPDH1), both involved in human immune response. They were then investigated with a molecular docking analysis approach. Our bioprospecting study indicated that many phytohormones may endow human health benefits, with potential functional role in multiple cellular processes including immune response and cell cycle progression.

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield. Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential. However, the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive. The purpose of this study was to clarify these issues. Three rice cultivars currently used in rice production, an IJHR cultivar Yongyou 2640 (YY2640), a japonica cultivar Lianjing 7 (LJ-7) and an indica cultivar Yangdao 6 (YD-6), were grown in the field with six N rates (0, 100, 200, 300, 400, and 500 kg ha−1) in 2018 and 2019. The results showed that with the increase in N application rates, the grain yield of each test cultivar increased at first and then decreased, and the highest grain yield was at the N rate of 400 kg ha−1 for YY2640, with a grain yield of 13.4 t ha−1, and at 300 kg ha−1 for LJ-7 and YD-6, with grain yields of 9.4–10.6 t ha−1. The grain yield and N use efficiency (NUE) of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate, especially at the higher N rates. When compared with LJ-7 or YD-6, YY2640 exhibited better physiological traits, including greater root oxidation activity and leaf photosynthetic rate, higher cytokinin content in the roots and leaves, and more remobilization of assimilates from the stem to the grain during grain filling. The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates. Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE, and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes.

A recent article in the Plant Journal explores the role of microRNA 394 (miR394) in regulating brassinosteroid (BR) signaling in plants. The study found that overexpression of miR394 resulted in phenotypes similar to BR-deficient mutants, including dwarfism and reduced elongation of leaves. The researchers also discovered that miR394 acts upstream of the BR signaling pathway, interacting with key components such as BIN2, BZR1, and BES1. Additionally, the study suggests that there is a feedback loop between miR394 and BR signaling, with BR signaling repressing the production of miR394. Further research is needed to understand the precise mechanisms by which miR394 influences BR signaling. [Extracted from the article]

Natural and synthetic phytohormones are widely used in agriculture. The synthetic cytokinin ethylenediurea (EDU) induces protection in plants against ozone phytotoxicity. In our study, new hybrid derivatives of EDU were synthesized and tested for phytoactivity. The germination potential (Gp), germination of seeds (G), and relative water content in leaves (RWC), characterizing the drought resistance of plants, were determined. The results of laboratory studies showed that EDU and its hybrid derivatives have a positive effect on root length, the growth and development of shoots, as well as the ability of plants to tolerate stress caused by a lack of water.

Members of the TaCKX gene family (GFM) encode oxidase/dehydrogenase cytokinin degrading enzymes (CKX), which play an important role in the homeostasis of phytohormones, affecting wheat development and productivity. Therefore, the objective of this investigation was to test how the expression patterns of the yield-related TaCKX genes and TaNAC2-5A (NAC2) measured in 7 days after pollination (DAP) spikes and the seedling roots of parents are inherited to apply this knowledge in the breeding process. The expression patterns of these genes were compared between parents and their F2 progeny in crosses of one mother with different paterns of awnless cultivars and reciprocal crosses of awned and awnless lines. We showed that most of the genes tested in the 7 DAP spikes and seedling roots of the F2 progeny showed paternal expression patterns in crosses of awnless cultivars as well as reciprocal crosses of awned and awnless lines. Consequently, the values of grain yield in the F2 progeny were similar to the pater; however, the values of seedling root mass were similar to the mother or both parents. The correlation analysis of TaCKX GFMs and NAC2 in spikes and spikes per seedling roots reveals that the genes correlate with each other specifically with the pater and the F2 progeny or the mother and the F2 progeny, which shape phenotypic traits. The numbers of spikes and semi-empty spikes are mainly correlated with the specific coexpression of the TaCKX and NAC2 genes expressed in spikes or spikes per roots of the pater and F2 progeny. Variable regression analysis of grain yield and root mass with TaCKX GFMs and NAC2 expressed in the tested tissues of five crosses revealed a significant dependency of these parameters on the mother and F2 and/or the pater and F2 progeny. We showed that the inheritance of yield-related traits depends on the specific cooperative expression of some TaCKX GFMs, in some crosses coupled with NAC2, and is strongly dependent on the genotypes used for the crosses. Indications for parental selection in the breeding of high-yielding lines are discussed.

Adaptation to changes in the environment depends, in part, on signaling between plant organs to integrate adaptive response at the level of the whole organism. Changes in the delivery of hormones from one organ to another through the vascular system strongly suggest that hormone transport is involved in the transmission of signals over long distances. However, there is evidence that, alternatively, systemic responses may be brought about by other kinds of signals (e.g., hydraulic or electrical) capable of inducing changes in hormone metabolism in distant organs. Long-distance transport of hormones is therefore a matter of debate. This review summarizes arguments for and against the involvement of the long-distance transport of cytokinins in signaling mineral nutrient availability from roots to the shoot. It also assesses the evidence for the role of abscisic acid (ABA) and jasmonates in long-distance signaling of water deficiency and the possibility that Lipid-Binding and Transfer Proteins (LBTPs) facilitate the long-distance transport of hormones. It is assumed that proteins of this type raise the solubility of hydrophobic substances such as ABA and jasmonates in hydrophilic spaces, thereby enabling their movement in solution throughout the plant. This review collates evidence that LBTPs bind to cytokinins, ABA, and jasmonates and that cytokinins, ABA, and LBTPs are present in xylem and phloem sap and co-localize at sites of loading into vascular tissues and at sites of unloading from the phloem. The available evidence indicates a functional interaction between LBTPs and these hormones.

The synthetic cytokinin forchlorfenuron (FCF), while seemingly presenting relatively low toxicity for mammalian organisms, has been the subject of renewed scrutiny in the past few years due to its increasing use in fruit crops and potential for bioaccumulation. Despite many toxicological properties of FCF being known, little research has been conducted on the toxicological effects of its secondary metabolites. Given this critical gap in the existing literature, understanding the formation of relevant FCF secondary metabolites and their association with mammalian metabolism is essential. To investigate the formation of FCF metabolites in sufficient quantities for toxicological studies, a panel of four fungi were screened for their ability to catalyze the biotransformation of FCF. Of the organisms screened, Cunninghamella elegans (ATCC 9245), a filamentous fungus, was found to convert FCF to 4-hydroxyphenyl-forchlorfenuron, the major FCF secondary metabolite identified in mammals, after 26 days. Following the optimization of biotransformation conditions using a solid support system, media screening, and inoculation with a solid pre-formed fungal mass of C. elegans, this conversion time was significantly reduced to 7 days—representing a 73% reduction in total reaction time as deduced from the biotransformation products and confirmed by LC-MS, NMR spectroscopic data, as well as a comparison with synthetically prepared metabolites. Our study provides the first report of the metabolism of FCF by C. elegans. These findings suggest that C. elegans can produce FCF secondary metabolites consistent with those produced via mammalian metabolism and could be used as a more efficient, cost-effective, and ethical alternative for producing those metabolites in useful quantities for toxicological studies.