Abscisic acid promotes jasmonic acid biosynthesis via a 'SAPK10-bZIP72-AOC' pathway to synergistically inhibit seed germination in rice (Oryza sativa)

OsJAZ10 negatively modulates the drought tolerance by integrating hormone signaling with systemic electrical activity in rice

Jasmonic acid (JA) plays crucial functions in plant stress response, and the synergistic interaction between JA and abscisic acid (ABA) signaling is implicated to help plants adapt to environmental challenges, whereas the underlying molecular mechanism still needs to be revealed. Here, we report that OsJAZ10, a repressor in the JA signaling, represses rice drought tolerance via inhibition of JA and ABA biosynthesis. Function loss of OsJAZ10 markedly enhances, while overexpression of OsJAZ10ΔJas reduces rice drought tolerance. The osjaz10 mutant is more sensitive to exogenous ABA and MeJA, and produces higher levels of ABA and JA after drought treatment, indicating OsJAZ10 represses the biosynthesis of these two hormones. Mechanistic study demonstrated that OsJAZ10 physically interacts with OsMYC2. Transient transcriptional regulation assays showed that OsMYC2 activates the expression of ABA-biosynthetic gene OsNCED2, JA-biosynthetic gene OsAOC, and drought-responsive genes OsRAB21 and OsLEA3, while OsJAZ10 prevents OsMYC2 transactivation of these genes. Further, the electrophoretic mobility shift assay (EMSA) confirmed that OsMYC2 directly binds to the promoters of OsNCED2 and OsRAB21. Electrical activity has been proposed to activate JA biosynthesis. Interestingly, OsJAZ10 inhibits the propagation of osmotic stress-elicited systemic electrical signals, indicated by the significantly increased PEG-elicited slow wave potentials (SWPs) in osjaz10 mutant, which is in accordance with the elevated JA levels. Collectively, our findings establish that OsJAZ10 functions as a negative regulator in rice drought tolerance by repressing JA and ABA biosynthesis, and reveal an important mechanism that plants integrate electrical events with hormone signaling to enhance the adaption to environmental stress.

Heterosis of endophytic microbiomes in hybrid rice varieties improves seed germination

Seed endophytic microbiomes are shaped by host and environmental factors and play a crucial role in their host growth and health. Studies have demonstrated that host genotype, including hybridization, affects seed microbiomes. Heterosis features are also observed in root-associated microbiomes. It remains unclear, however, whether heterosis exists in seed endophytic microbiomes and whether hybrid microbiota provide noticeable advantages to host plant growth, especially to seed germination. Here, we investigated the structure of seed endophytic bacterial and fungal communities from three hybrid rice varieties and their respective parents using amplicon sequencing targeting 16S rRNA and ITS2 genes. Heterosis was found in diversity and composition of seed endophytic microbiomes in hybrids, which hosted more diverse communities and significantly higher abundances of plant growth-promoting taxa, such as Pseudomonas and Rhizobium genera compared with their parental lines. Co-occurrence network analysis revealed that there are potentially tighter microbial interactions in the hybrid seeds compared with their parent seeds. Finally, inoculation of seed-cultivable endophytes, isolated from hybrids, resulted in a greater promotion of seed germination compared with those isolated from parent lines. These findings suggest that heterosis exists not only in plant traits but also in seed endophytic microbiota, the latter in turn promotes seed germination, which offers valuable guidance for microbiome-assisted rice breeding.IMPORTANCEGenetic and physiological changes associated with plant hybridization have been studied for many crop species. Still, little is known about the impact of hybridization on the seed microbiota. In this study, we indicate that hybridization has a significant impact on the endophytic bacterial and fungal communities in rice seeds. The seed endophytic microbiomes of hybrids displayed distinct characteristics from those of their parental lines and exhibited potential heterosis features. Furthermore, the inoculation of seed-cultivable endophytes isolated from hybrids exhibited a greater promotion effect on seed germination compared with those isolated from the parents. Our findings make a valuable contribution to the emerging field of microbiome-assisted plant breeding, highlighting the potential for a targeted approach that aims to achieve not only desired plant traits but also plant-beneficial microbial communities on the seeds.

OsBBP1, a newly identified protein containing DUF630 and DUF632 domains confers drought tolerance in rice

Domain of unknown function (DUF) protein families, which are uncharacterized and numerous within the Pfam database. Recently, studies have demonstrated that DUFs played crucial roles in plant development, but whether, or how, they function in drought resistance remain unclear. In this study, we identified the Os03g0321500 gene, encoding OsbZIP72 binding protein 1 (OsBBP1), as a target of OsbZIP72 using chromatin immunoprecipitation sequencing in rice. OsBBP1 is a novel member of DUFs, which localize both in the nuclei and cytoplasm of rice protoplasts. Furthermore, yeast one-hybrid and electrophoretic mobility shift assays confirmed the specific binding between OsbZIP72 and OsBBP1. Additionally, a luciferase reporter analysis illustrated that OsbZIP72 activated the expression of OsBBP1. Drought tolerance experiments demonstrate that the OsBBP1 CRISPER-CAS9 transgenic mutants were sensitive to drought stress, but the transgenic OsBBP1 over-expressing rice plants showed enhanced drought resistance. Moreover, drought tolerance experiments in a paddy field suggested that OsBBP1 contributed to less yield or yield-related losses under drought conditions. Mechanistically, OsBBP1 might confer drought resistance by inducing more efficient reactive oxygen species (ROS) scavenging. Several ROS scavenging-related genes showed increased expression levels in OsBBP1 overexpression lines and decreased expression levels in OsBBP1 CRISPER-CAS9 mutants under drought conditions. Thus, OsBBP1, acting downstream of OsbZIP72, contributes to drought resistance and causes less yield or yield-related losses under drought conditions.

A bamboo 'PeSAPK4-PeMYB99-PeTIP4-3' regulatory model involved in water transport

Water plays crucial roles in expeditious growth and osmotic stress of bamboo. Nevertheless, the molecular mechanism of water transport remains unclear. In this study, an aquaporin gene, PeTIP4-3, was identified through a joint analysis of root pressure and transcriptomic data in moso bamboo (Phyllostachys edulis). PeTIP4-3 was highly expressed in shoots, especially in the vascular bundle sheath cells. Overexpression of PeTIP4-3 could increase drought and salt tolerance in transgenic yeast and rice. A co-expression pattern of PeSAPK4, PeMYB99 and PeTIP4-3 was revealed by WGCNA. PeMYB99 exhibited an ability to independently bind to and activate PeTIP4-3, which augmented tolerance to drought and salt stress. PeSAPK4 could interact with and phosphorylate PeMYB99 in vivo and in vitro, wherein they synergistically accelerated PeTIP4-3 transcription. Overexpression of PeMYB99 and PeSAPK4 also conferred drought and salt tolerance in transgenic rice. Further ABA treatment analysis indicated that PeSAPK4 enhanced water transport in response to stress via ABA signaling. Collectively, an ABA-mediated cascade of PeSAPK4-PeMYB99-PeTIP4-3 is proposed, which governs water transport in moso bamboo.

OsLESV and OsESV1 promote transitory and storage starch biosynthesis to determine rice grain quality and yield

Transitory starch is an important carbon source in leaves, and its biosynthesis and metabolism are closely related to grain quality and yield. The molecular mechanisms controlling leaf transitory starch biosynthesis and degradation and their effects on rice (Oryza sativa) quality and yield remain unclear. Here, we show that OsLESV and OsESV1, the rice orthologs of AtLESV and AtESV1, are associated with transitory starch biosynthesis in rice. The total starch and amylose contents in leaves and endosperms are significantly reduced, and the final grain quality and yield are compromised in oslesv and osesv1 single and oslesv esv1 double mutants. Furthermore, we found that OsLESV and OsESV1 bind to starch, and this binding depends on a highly conserved C-terminal tryptophan-rich region that acts as a starch-binding domain. Importantly, OsLESV and OsESV1 also interact with the key enzymes of starch biosynthesis, granule-bound starch synthase I (GBSSI), GBSSII, and pyruvate orthophosphote dikiase (PPDKB), to maintain their protein stability and activity. OsLESV and OsESV1 also facilitate the targeting of GBSSI and GBSSII from plastid stroma to starch granules. Overexpression of GBSSI, GBSSII, and PPDKB can partly rescue the phenotypic defects of the oslesv and osesv1 mutants. Thus, we demonstrate that OsLESV and OsESV1 play a key role in regulating the biosynthesis of both leaf transitory starch and endosperm storage starch in rice. These findings deepen our understanding of the molecular mechanisms underlying transitory starch biosynthesis in rice leaves and reveal how the transitory starch metabolism affects rice grain quality and yield, providing useful information for the genetic improvement of rice grain quality and yield.

A peroxisomal cinnamate:CoA ligase-dependent phytohormone metabolic cascade in submerged rice germination

The mechanism underlying the ability of rice to germinate underwater is a largely enigmatic but key research question highly relevant to rice cultivation. Moreover, although rice is known to accumulate salicylic acid (SA), SA biosynthesis is poorly defined, and its role in underwater germination is unknown. It is also unclear whether peroxisomes, organelles essential to oilseed germination and rice SA accumulation, play a role in rice germination. Here, we show that submerged imbibition of rice seeds induces SA accumulation to promote germination in submergence. Two submergence-induced peroxisomal Oryza sativa cinnamate:CoA ligases (OsCNLs) are required for this SA accumulation. SA exerts this germination-promoting function by inducing indole-acetic acid (IAA) catabolism through the IAA-amino acid conjugating enzyme GH3. The metabolic cascade we identified may potentially be adopted in agriculture to improve the underwater germination of submergence-intolerant rice varieties. SA pretreatment is also a promising strategy to improve submerged rice germination in the field.

Silencing an ATP-Dependent Caseinolytic Protease Proteolytic Subunit Gene Enhances the Resistance of Rice to Nilaparvata lugens

The ATP-dependent caseinolytic protease (Clp) system has been reported to play an important role in plant growth, development, and defense against pathogens. However, whether the Clp system is involved in plant defense against herbivores remains largely unclear. We explore the role of the Clp system in rice defenses against brown planthopper (BPH) Nilaparvata lugens by combining chemical analysis, transcriptome, and molecular analyses, as well as insect bioassays. We found the expression of a rice Clp proteolytic subunit gene, OsClpP6, was suppressed by infestation of BPH gravid females and mechanical wounding. Silencing OsClpP6 enhanced the level of BPH-induced jasmonic acid (JA), JA-isoleucine (JA-Ile), and ABA, which in turn promoted the production of BPH-elicited rice volatiles and increased the resistance of rice to BPH. Field trials showed that silencing OsClpP6 decreased the population densities of BPH and WBPH. We also observed that silencing OsClpP6 decreased chlorophyll content in rice leaves at early developmental stages and impaired rice root growth and seed setting rate. These findings demonstrate that an OsClpP6-mediated Clp system in rice was involved in plant growth-defense trade-offs by affecting the biosynthesis of defense-related signaling molecules in chloroplasts. Moreover, rice plants, after recognizing BPH infestation, can enhance rice resistance to BPH by decreasing the Clp system activity. The work might provide a new way to breed rice varieties that are resistant to herbivores.

Identification of a sugarcane bacilliform virus promoter that is activated by drought stress in plants

Sugarcane (Saccharum spp.) is an important sugar and biofuel crop in the world. It is frequently subjected to drought stress, thus causing considerable economic losses. Transgenic technology is an effective breeding approach to improve sugarcane tolerance to drought using drought-inducible promoter(s) to activate drought-resistance gene(s). In this study, six different promoters were cloned from sugarcane bacilliform virus (SCBV) genotypes exhibiting high genetic diversity. In β-glucuronidase (GUS) assays, expression of one of these promoters (PSCBV-YZ2060) is similar to the one driven by the CaMV 35S promoter and >90% higher compared to the other cloned promoters and Ubi1. Three SCBV promoters (PSCBV-YZ2060, PSCBV-TX, and PSCBV-CHN2) function as drought-induced promoters in transgenic Arabidopsis plants. In Arabidopsis, GUS activity driven by promoter PSCBV-YZ2060 is also upregulated by abscisic acid (ABA) and is 2.2-5.5-fold higher when compared to the same activity of two plant native promoters (PScRD29A from sugarcane and PAtRD29A from Arabidopsis). Mutation analysis revealed that a putative promoter region 1 (PPR1) and two ABA response elements (ABREs) are required in promoter PSCBV-YZ2060 to confer drought stress response and ABA induction. Yeast one-hybrid and electrophoretic mobility shift assays uncovered that transcription factors ScbZIP72 from sugarcane and AREB1 from Arabidopsis bind with two ABREs of promoter PSCBV-YZ2060. After ABA treatment or drought stress, the expression levels of endogenous ScbZIP72 and heterologous GUS are significantly increased in PSCBV-YZ2060:GUS transgenic sugarcane plants. Consequently, promoter PSCBV-YZ2060 is a possible alternative promoter for genetic engineering of drought-resistant transgenic crops such as sugarcane.

OsNAC120 balances plant growth and drought tolerance by integrating GA and ABA signaling in rice

The crosstalk between gibberellin (GA) and abscisic acid (ABA) signaling is crucial for balancing plant growth and adaption to environmental stress. Nevertheless, the molecular mechanism of their mutual antagonism still remains to be fully clarified. In this study, we found that knockout of the rice NAC (NAM, ATAF1/2, CUC2) transcription factor gene OsNAC120 inhibits plant growth but enhances drought tolerance, whereas OsNAC120 overexpression produces the opposite results. Exogenous GA can rescue the semi-dwarf phenotype of osnac120 mutants, and further study showed that OsNAC120 promotes GA biosynthesis by transcriptionally activating the GA biosynthetic genes OsGA20ox1 and OsGA20ox3. The DELLA protein SLENDER RICE1 (SLR1) interacts with OsNAC120 and impedes its transactivation ability, and GA treatment can remove the inhibition of transactivation activity caused by SLR1. On the other hand, OsNAC120 negatively regulates rice drought tolerance by repressing ABA-induced stomatal closure. Mechanistic investigation revealed that OsNAC120 inhibits ABA biosynthesis via transcriptional repression of the ABA biosynthetic genes OsNCED3 and OsNCED4. Rice OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE 9 (OsSAPK9) physically interacts with OsNAC120 and mediates its phosphorylation, which results in OsNAC120 degradation. ABA treatment accelerates OsNAC120 degradation and reduces its transactivation activity. Together, our findings provide evidence that OsNAC120 plays critical roles in balancing GA-mediated growth and ABA-induced drought tolerance in rice. This research will help us to understand the mechanisms underlying the trade-off between plant growth and stress tolerance and to engineer stress-resistant, high-yielding crops.

Endomembrane-biased dimerization of ABCG16 and ABCG25 transporters determines their substrate selectivity in ABA-regulated plant growth and stress responses

ATP-binding cassette (ABC) transporters are integral membrane proteins that have evolved diverse functions fulfilled via the transport of various substrates. In Arabidopsis, the G subfamily of ABC proteins is particularly abundant and participates in multiple signaling pathways during plant development and stress responses. In this study, we revealed that two Arabidopsis ABCG transporters, ABCG16 and ABCG25, engage in ABA-mediated stress responses and early plant growth through endomembrane-specific dimerization-coupled transport of ABA and ABA-glucosyl ester (ABA-GE), respectively. We first revealed that ABCG16 contributes to osmotic stress tolerance via ABA signaling. More specifically, ABCG16 induces cellular ABA efflux in both yeast and plant cells. Using FRET analysis, we showed that ABCG16 forms obligatory homodimers for ABA export activity and that the plasma membrane-resident ABCG16 homodimers specifically respond to ABA, undergoing notable conformational changes. Furthermore, we demonstrated that ABCG16 heterodimerizes with ABCG25 at the endoplasmic reticulum (ER) membrane and facilitates the ER entry of ABA-GE in both Arabidopsis and tobacco cells. The specific responsiveness of the ABCG16-ABCG25 heterodimer to ABA-GE and the superior growth of their double mutant support an inhibitory role of these two ABCGs in early seedling establishment via regulation of ABA-GE translocation across the ER membrane. Our endomembrane-specific analysis of the FRET signals derived from the homo- or heterodimerized ABCG complexes allowed us to link endomembrane-biased dimerization to the translocation of distinct substrates by ABCG transporters, providing a prototypic framework for understanding the omnipotence of ABCG transporters in plant development and stress responses.

The F-box protein ZmFBL41 negatively regulates disease resistance to Rhizoctonia solani by degrading the abscisic acid synthase ZmNCED6 in maize

KEY MESSAGE

The maize F-box protein ZmFBL41 targets abscisic acid synthase 9-cis-epoxycarotenoid dioxygenase 6 for degradation, and this regulatory module is exploited by Rhizoctonia solani to promote infection. F-box proteins are crucial regulators of plant growth, development, and responses to abiotic and biotic stresses. Previous research identified the F-box gene ZmFBL41 as a negative regulator of maize (Zea mays) defenses against Rhizoctonia solani. However, the precise mechanisms by which F-box proteins mediate resistance to R. solani remain poorly understood. In this study, we show that ZmFBL41 interacts with an abscisic acid (ABA) synthase, 9-cis-epoxycarotenoid dioxygenase 6 (ZmNCED6), promoting its degradation via the ubiquitination pathway. We discovered that the ectopic overexpression of ZmNCED6 in rice (Oryza sativa) inhibited R. solani infection by activating stomatal closure, callose deposition, and jasmonic acid (JA) biosynthesis, indicating that ZmNCED6 enhances plant immunity against R. solani. Natural variation at ZmFBL41 across different maize haplotypes did not affect the ZmFBL41-ZmNCED6 interaction. These findings suggest that ZmFBL41 targets ZmNCED6 for degradation, leading to a decrease in ABA levels in maize, in turn, inhibiting ABA-mediated disease resistance pathways, such as stomatal closure, callose deposition, and JA biosynthesis, ultimately facilitating R. solani infection.

Rice tetraspanins express in specific domains of diverse tissues and regulate plant architecture and root growth

Tetraspanins (TETs) are small transmembrane scaffold proteins that distribute proteins into highly organized microdomains, consisting of adaptors and signaling proteins, which play important roles in various biological events. In plants, understanding of tetraspanin is limited to the Arabidopsis TET genes' expression pattern and their function in leaf and root growth. Here, we comprehensively analyzed all rice tetraspanin (OsTET) family members, including their gene expression pattern, protein topology, and subcellular localization. We found that the core domain of OsTETs is conserved and shares a similar topology of four membrane-spanning domains with animal and plant TETs. OsTET genes are partially overlapping expressed in diverse tissue domains in vegetative and reproductive organs. OsTET proteins preferentially targeted the endoplasmic reticulum. Mutation analysis showed that OsTET5, OsTET6, OsTET9, and OsTET10 regulated plant height and tillering, and that OsTET13 controlled root growth in association with the jasmonic acid pathway. In summary, our work provides systematic new insights into the function of OsTETs in rice growth and development, and the data provides valuable resources for future research.

CeO2NP priming enhances the seed vigor of alfalfa (Medicago sativa) under salt stress

Soil salinization is a common environmental problem that seriously threatens crop yield and food security, especially through its impact on seed germination. Nanoparticle priming, an emerging seed treatment method, is receiving increasing attention in improving crop yield and stress resistance. This study used alfalfa seeds as materials to explore the potential benefits of cerium oxide nanoparticle (CeO2NP) priming to promote seed germination and improve salt tolerance. CeO2NPs at concentrations up to 500 mg/L were able to significantly alleviate salt stress in alfalfa seeds (200 mM), with 50 mg/L of CeO2NP having the best effect, significantly (P< 0.05) increasing germination potential (from 4.0% to 51.3%), germination rate (from 10.0% to 62.7%), root length (from 8.3 cm to 23.1 cm), and seedling length (from 9.8 cm to 13.7 cm). Priming treatment significantly (P< 0.05) increased seed water absorption by removing seed hardness and also reducing abscisic acid and jasmonic acid contents to relieve seed dormancy. CeO2NP priming increased α-amylase activity and osmoregulatory substance level, decreased reactive oxygen species and malonaldehyde contents and relative conductivity, and increased catalase enzyme activity. Seed priming regulated carotenoid, zeatin, and plant hormone signal transduction pathways, among other metabolic pathways, while CeO2NP priming additionally promoted the enrichment of α-linolenic acid and diterpenoid hormone metabolic pathways under salt stress. In addition, CeO2NPs enhanced α-amylase activity (by 6.55%) in vitro. The optimal tested concentration (50 mg/L) of CeO2NPs was able to improve the seed vigor, enhance the activity of α-amylase, regulate the osmotic level and endogenous hormone levels, and improve the salt tolerance of alfalfa seeds. This study demonstrates the efficacy of a simple seed treatment strategy that can improve crop stress resistance, which is of great importance for reducing agricultural costs and promoting sustainable agricultural development.

Regulatory function of the endogenous hormone in the germination process of quinoa seeds

The economic and health significance of quinoa is steadily growing on a global scale. Nevertheless, the primary obstacle to achieving high yields in quinoa cultivation is pre-harvest sprouting (PHS), which is intricately linked to seed dormancy. However, there exists a dearth of research concerning the regulatory mechanisms governing PHS. The regulation of seed germination by various plant hormones has been extensively studied. Consequently, understanding the mechanisms underlying the role of endogenous hormones in the germination process of quinoa seeds and developing strategies to mitigate PHS in quinoa cultivation are of significant research importance. This study employed the HPLC-ESI-MS/MS internal standard and ELISA method to quantify 8 endogenous hormones. The investigation of gene expression changes before and after germination was conducted using RNA-seq analysis, leading to the discovery of 280 differentially expressed genes associated with the regulatory pathway of endogenous hormones. Additionally, a correlation analysis of 99 genes with significant differences identified 14 potential genes that may act as crucial "transportation hubs" in hormonal interactions. Through the performance of an analysis on the modifications in hormone composition and the expression of associated regulatory genes, we posit a prediction that implies the presence of a negative feedback regulatory mechanism of endogenous hormones during the germination of quinoa seeds. This mechanism is potentially influenced by the unique structure of quinoa seeds. To shed light on the involvement of endogenous hormones in the process of quinoa seed germination, we have established a regulatory network. This study aims to offer innovative perspectives on the breeding of quinoa varieties that exhibit resistance to PHS, as well as strategies for preventing PHS.

Dynamic changes in the levels of metabolites and endogenous hormones during the germination of Zanthoxylum nitidum (Roxb.) DC. Seeds

Accumulating experimental data have shown that endogenous hormones play important roles in regulating seed dormancy and germination. Zanthoxylum nitidum is a medicinal plant that propagates via seeds, which require a long dormancy period for normal germination, and complex changes in metabolites occur during the germination process. However, the regulatory network of endogenous hormones and metabolites during the germination of Z. nitidum seeds remains unclear. This study investigated the dynamic changes in the levels of metabolites and endogenous hormones during the germination of Z. nitidum seeds. The results revealed an increase in the levels of gibberellin 3 (GA3), 12-oxophytodienoic acid (OPDA), 1-aminocyclopropane-1-carboxylic acid (ACC) and trans-zeatin (TZ) and decrease in the levels of abscisic acid (ABA), jasmonic acid (JA), N-[(-)-jasmonoyl]-(S)-isoleucine (JA-Ile) and trans-zeatin riboside (TZR). Overall, 112 differential metabolites (DAMs) were screened from 3 seed samples (Sa, Sb and Sc), most of which are related to primary metabolism. A total of 16 DAMs (including 3 monosaccharides, 3 phosphate lipids, 3 carboxylic acids, 1 amino acid, 2 pyrimidines, and 4 nucleotides) were identified in the three sample comparison pairs (Sa vs Sb, Sa vs Sc, and Sb vs Sc); these DAMs were significantly enriched in purine metabolism; glycerophospholipid metabolism, citrate cycle (TCA cycle), alanine, aspartate and glutamate metabolism and pyruvate metabolism. OPDA, ACC and GAs were significantly positively correlated with upregulated metabolites, whereas ABA and JA were significantly positively correlated with downregulated metabolites. Finally, a hypothetical metabolic network of endogenous hormones that regulate seed germination was constructed. This study deepens our understanding of the importance of endogenous hormonal profiles that mediate seed germination.

Phosphate Transporter OsPT4, Ubiquitinated by E3 Ligase OsAIRP2, Plays a Crucial Role in Phosphorus and Nitrogen Translocation and Consumption in Germinating Seed

Phosphorus (P) and nitrogen (N) are essential macronutrients necessary for plant growth and development. OsPT4 is a high-affinity phosphate (Pi) transporter that has a positive impact on nutrient uptake and seed development. In this study, the expression patterns of different Pi transporter genes in germinating seeds were determined, and the relative expression of OsPT4 was induced in Pi-deficient seeds and gradually increased with the passage of germination time. The analysis of P, N, Pi, and amino acid concentrations in germinating seeds of OsPT4 mutants showed that the OsPT4 mutation caused P and N retention and a continuous reduction in multiple amino acid concentrations in germinating seeds. Transcriptome analysis and qRT-PCR results also indicated that the OsPT4 mutation inhibits the expression of genes related to P and N transportation and amino acid synthesis in germinating seeds. In addition, the paraffin section and TUNEL assay of OsPT4 mutant germinating seeds suggests that OsPT4 mutation causes programmed cell death (PCD) delayed in the aleurone layer and inhibition of leaf outgrowth. Moreover, we also found that OsPT4 was ubiquitinated by OsAIRP2, which is a C3HC4-type RING E3 Ub ligase. Our studies illustrate that OsPT4 plays a crucial role in P and N collaborative translocation and consumption in germinating seeds. It also provides a theoretical basis for the molecules and physiological mechanisms of P and N cross-talk under suppressed Pi uptake conditions.

Ethanol suppresses rice seed germination through inhibiting ROS signaling

Ethanol is frequently used not only as priming but also as a solvent to dissolve hardly water-soluble phytohormones gibberellic acid (GA3) and abscisic acid (ABA) in seed germination. However, the molecular and physiological mechanisms of ethanol's impact on seed germination remain elusive. In this report, we investigated how ethanol affected reactive oxygen species (ROS) during rice seed germination. Ethanol at a concentration of 3.5% (v/v) inhibited 90% seed germination, which was almost reversed by H2O2. H2O2 contents in embryos were reduced by ethanol after 18 h imbibition. Antioxidant enzymes assays revealed that only superoxide dismutase (SOD) activities in seed embryos were lowered by ethanol, in line with the suppressed mRNA expression of SOD genes during imbibition. Additionally, compared to the mock condition, ethanol increased ABA contents but decreased GA (GA1 and GA3) in seed embryos, resulting in disharmonizing GA/ABA balance. Conceivably ethanol induced transcription of OsNCEDs, the key genes for ABA biosynthesis, and OsABA8ox3, a key gene for ABA catabolism. Furthermore, ethanol promoted ABA signaling by upregulating ABA receptor genes and ABA-responsive element (ABRE)-binding protein/ABRE-binding factors during imbibition. Overall, our results demonstrate that lowering of H2O2 levels due to suppressed SOD activities in rice germinating seed embryos is the decisive factor for ethanol-induced inhibition of seed germination, and GA/ABA balance and ABA signaling also play important roles in ethanol's inhibitory impact on seed germination.

Nuclear factor OsNF-YC5 modulates rice seed germination by regulating synergistic hormone signaling

Regulation of seed dormancy/germination is of great importance for seedling establishment and crop production. Nuclear factor-Y (NF-Y) transcription factors regulate plant growth and development, as well as stress responses; however, their roles in seed germination remain largely unknown. In this study, we reported that NF-Y gene OsNF-YC5 knockout increased, while its overexpression reduced, the seed germination in rice (Oryza sativa L.). ABA-induced seed germination inhibition assays showed that the osnf-yc5 mutant was less sensitive but OsNF-YC5-overexpressing lines were more sensitive to exogenous ABA than the wild type. Meanwhile, MeJA treatment substantially enhanced the ABA sensitivity of OsNF-YC5-overexpressing lines during seed germination. Mechanistic investigations revealed that the interaction of OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE 9 (SAPK9) with OsNF-YC5 enhanced the stability of OsNF-YC5 by protein phosphorylation, while the interaction between JASMONATE ZIM-domain protein 9 (OsJAZ9) and OsNF-YC5 repressed OsNF-YC5 transcriptional activity and promoted its degradation. Furthermore, OsNF-YC5 transcriptionally activated ABA catabolic gene OsABA8ox3, reducing ABA levels in germinating seeds. However, the transcriptional regulation of OsABA8ox3 by OsNF-YC5 was repressed by addition of OsJAZ9. Notably, OsNF-YC5 improved seed germination under salinity conditions. Further investigation showed that OsNF-YC5 activated the high-affinity K+ transporter gene (OsHAK21) expression, and addition of SAPK9 could increase the transcriptional regulation of OsHAK21 by OsNF-YC5, thus substantially reducing the ROS levels to enhance seed germination under salt stress. Our findings establish that OsNF-YC5 integrates ABA and JA signaling during rice seed germination, shedding light on the molecular networks of ABA-JA synergistic interaction.

Roles of the pepper JAZ protein CaJAZ1-03 and its interacting partner RING-type E3 ligase CaASRF1 in regulating ABA signaling and drought responses

Plants have developed various defense mechanisms against environmental stresses by regulating hormone signaling. Jasmonic acid (JA) is a major phytohormone associated with plant defense responses. JASMONATE ZIM-DOMAIN (JAZ) proteins play a regulatory role in repressing JA signaling, impacting plant responses to both biotic and abiotic stresses. Here, we isolated 7 JAZ genes in pepper and selected CA03g31030, a Capsicum annuum JAZ1-03 (CaJAZ1-03) gene, for further study based on its expression level in response to abiotic stresses. Through virus-induced gene silencing (VIGS) in pepper and overexpression in transgenic Arabidopsis plants, we established the functional role of CaJAZ1-03. Functional studies revealed that CaJAZ1-03 dampens abscisic acid (ABA) signaling and drought stress responses. The cell-free degradation assay showed faster degradation of CaJAZ1-03 in drought- or ABA-treated pepper leaves compared to healthy leaves. Conversely, CaJAZ1-03 was completely preserved under MG132 treatment, indicating that CaJAZ1-03 stability is modulated via the ubiquitin-26s proteasome pathway. We also found that the pepper RING-type E3 ligase CaASRF1 interacts with and ubiquitinates CaJAZ1-03. Additional cell-free degradation assays revealed a negative correlation between CaJAZ1-03 and CaASRF1 expression levels. Collectively, these findings suggest that CaJAZ1-03 negatively regulates ABA signaling and drought responses and that its protein stability is modulated by CaASRF1.

Insights from multi-omics integration into seed germination of Taxus chinensis var mairei

The transition from deep dormancy to seed germination is essential for the life cycle of plants, but how this process occurs in the gymnosperm Chinese yew (Taxus chinensis var mairei), the natural source of the anticancer drug paclitaxel, remains unclear. Herein, we analyse the transcriptome, proteome, spatial metabolome, and spatial lipidome of the Chinese yew and present the multi-omics profiles of dormant and germinating seeds. Our results show that abscisic acid and gibberellic acid 12 homoeostasis is closely associated with gene transcription and protein translation, and the balance between these phytohormones thereby determines if seeds remain dormant or germinate. We find that an energy supply of carbohydrates from glycolysis and the TCA cycle feed into the pentose phosphate pathway during seed germination, and energy supplied from lipids are mainly derived from the lipolysis of triacylglycerols. Using mass spectrometry imaging, we demonstrate that the spatial distribution of plant hormones and phospholipids has a remarkable influence on embryo development. We also provide an atlas of the spatial distribution of paclitaxel C in Chinese yew seeds for the first time. The data from this study enable exploration of the germination mechanism of Chinese yew seeds across several omics levels.

The E3 ubiquitin ligase OsRGLG5 targeted by the Magnaporthe oryzae effector AvrPi9 confers basal resistance against rice blast

Rice blast, caused by Magnaporthe oryzae, is one of the most devastating diseases of rice. During infection, M. oryzae secretes effectors to facilitate blast development. Among these effectors, the avirulence factor AvrPi9 is recognized by Pi9, a broad-spectrum blast resistance protein that triggers Pi9-mediated resistance in rice. However, little is known about the interaction between AvrPi9 and Pi9 and how AvrPi9 exerts virulence to promote infection. In this study, we found that ectopic expression of AvrPi9 in the Pi9-lacking cultivar TP309 suppressed basal resistance against M. oryzae. Furthermore, we identified an AvrPi9-interacting protein in rice, which we named OsRGLG5, encoding a functional RING-type E3 ubiquitin ligase. During infection, AvrPi9 was ubiquitinated and degraded by OsRGLG5. Meanwhile, AvrPi9 affected the stability of OsRGLG5. Infection assays revealed that OsRGLG5 is a positive regulator of basal resistance against M. oryzae, but it is not essential for Pi9-mediated blast resistance in rice. In conclusion, our results revealed that OsRGLG5 is targeted by the M. oryzae effector AvrPi9 and positively regulates basal resistance against rice blast.

OsPMS1 Mutation Enhances Salt Tolerance by Suppressing ROS Accumulation, Maintaining Na+/K+ Homeostasis, and Promoting ABA Biosynthesis

World-wide, rice (Oryza sativa L.) is an important food source, and its production is often adversely affected by salinity. Therefore, to ensure stable rice yields for global food security, it is necessary to understand the salt tolerance mechanism of rice. The present study focused on the expression pattern of the rice mismatch repair gene post-meiotic segregation 1 (OsPMS1), studied the physiological properties and performed transcriptome analysis of ospms1 mutant seedlings in response to salt stress. Under normal conditions, the wild-type and ospms1 mutant seedlings showed no significant differences in growth and physiological indexes. However, after exposure to salt stress, compared with wild-type seedlings, the ospms1 mutant seedlings exhibited increased relative water content, relative chlorophyll content, superoxide dismutase (SOD) activity, K+ and abscisic acid (ABA) content, and decreased malondialdehyde (MDA) content, Na+ content, and Na+/K+ ratio, as well as decreased superoxide anion (O2-) and hydrogen peroxide (H2O2) accumulation. Gene ontology (GO) analysis of the differentially expressed genes (DEGs) of ospms1 mutant seedlings treated with 0 mM and 150 mM NaCl showed significant enrichment in biological and cytological processes, such as peroxidase activity and ribosomes. The Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis showed that the DEGs specifically enriched ascorbate and aldarate metabolism, flavone and flavonol biosynthesis, and glutathione metabolism pathways. Further quantitative real-time reverse transcription-PCR (qRT-PCR) analysis revealed significant changes in the transcription levels of genes related to abscisic acid signaling (OsbZIP23, OsSAPK6, OsNCED4, OsbZIP66), reactive oxygen scavenging (OsTZF1, OsDHAR1, SIT1), ion transport (OsHAK5), and osmoregulation (OsLEA3-2). Thus, the study's findings suggest that the ospms1 mutant tolerates salt stress at the seedling stage by inhibiting the accumulation of reactive oxygen species, maintaining Na+ and K+ homeostasis, and promoting ABA biosynthesis.

Spermidine enhances chilling tolerance of kale seeds by modulating ROS and phytohormone metabolism

Chilling stress is an important constraint for kale seed germination and seedlings establishment. It is vital to develop an effective approach to enhance kale seed germination ability under chilling stress. The present study reported that spermidine (Spd) could improve seed chilling tolerance in two kale cultivars 'Nagoya' (MGW) and 'Pigeon' (BB) during germination. The results showed that MGW was cold tolerant with a 90.67% germination percentage (GP) under chilling stress, while BB was cold sensitive with a 70.67% GP under chilling stress. Spd content in MGW and BB seeds during seed germination were up-regulated and down-regulated by chilling stress, respectively. Besides, chilling stress apparently decreased the gibberellin (GA) and ethylene (ET) contents, while increased the levels of abscisic acid (ABA) and reactive oxygen species (ROS) in MGW and BB seeds during germination. Exogenous Spd application increased GA, ET contents and decreased ABA content through regulating the gene expressions of metabolic-related enzymes, thus effectively alleviating the low temperature damage on kale seed germination. Besides, Spd significantly increased the activities of superoxide dismutase (SOD) and peroxidase (POD), and reduced the levels of hydrogen peroxide (H2O2) and superoxide anion (O2·-). The present study demonstrated that endogenous Spd metabolism plays an important role in kale seed germination under chilling stress. The effect of exogenous Spd on the metabolism of endogenous Spd, GA, ABA, ET and antioxidant enzymes might be the important reason for promoting the kale seed vigor at low temperature.

A mulberry 9-cis-epoxycarotenoid dioxygenase gene MaNCED1 is involved in plant growth regulation and confers salt and drought tolerance in transgenic tobacco

The phytohormone abscisic acid (ABA) is vital in regulating root elongation, seed germination, and abiotic stress responses in plants. Conversely, the mechanisms of ABA in mulberry root growth, seed germination, and abiotic stress responses are poorly understood. Here, we reported that exogenous ABA and drought treatment inhibited the growth of mulberry seedlings but significantly increased the ratio of root/stem. Inhibition of ABA synthesis by fluridone and sodium tungstate resulted in the decrease of root/stem ratio. We also showed that the expression of MaNCED1 in the root was strongly induced by drought and salt stress. Increasing the expression of MaNCED1 in tobacco using overexpression leads to increased root elongation and reduced seed germination. Compared with the wild type, the accumulation of H2O2 and MDA was reduced, while the POD activity and proline content was increased in the transgenic plants after drought and salt treatment. Further studies revealed increased resistance to drought and salt stress in MaNCED1 overexpressed tobaccos. Meanwhile, the auxin and ethylene signal pathway-related gene expression levels increased in MaNCED1 overexpressed tobaccos. This study demonstrated the roles of mulberry MaNCED1 in regulating plant development and abiotic stress responses. It gave further insights into the coordinated regulation of ABA, auxin, and ethylene in seed growth and germination.

ABF1 Positively Regulates Rice Chilling Tolerance via Inducing Trehalose Biosynthesis

Chilling stress seriously limits grain yield and quality worldwide. However, the genes and the underlying mechanisms that respond to chilling stress remain elusive. This study identified ABF1, a cold-induced transcription factor of the bZIP family. Disruption of ABF1 impaired chilling tolerance with increased ion leakage and reduced proline contents, while ABF1 over-expression lines exhibited the opposite tendency, suggesting that ABF1 positively regulated chilling tolerance in rice. Moreover, SnRK2 protein kinase SAPK10 could phosphorylate ABF1, and strengthen the DNA-binding ability of ABF1 to the G-box cis-element of the promoter of TPS2, a positive regulator of trehalose biosynthesis, consequently elevating the TPS2 transcription and the endogenous trehalose contents. Meanwhile, applying exogenous trehalose enhanced the chilling tolerance of abf1 mutant lines. In summary, this study provides a novel pathway 'SAPK10-ABF1-TPS2' involved in rice chilling tolerance through regulating trehalose homeostasis.

SlMYB99-mediated auxin and abscisic acid antagonistically regulate ascorbic acids biosynthesis in tomato

Ascorbic acid (AsA) is a water-soluble antioxidant that plays important roles in plant development and human health. Understanding the regulatory mechanism underlying AsA biosynthesis is imperative to the development of high AsA plants. In this study, we reveal that the auxin response factor SlARF4 transcriptionally inhibits SlMYB99, which subsequently modulates AsA accumulation via transcriptional activation of AsA biosynthesis genes GPP, GLDH, and DHAR. The auxin-dependent transcriptional cascade of SlARF4-SlMYB99-GPP/GLDH/DHAR modulates AsA synthesis, while mitogen-activated protein kinase SlMAPK8 not only phosphorylates SlMYB99, but also activates its transcriptional activity. Both SlMYB99 and SlMYB11 proteins physically interact with each other, thereby synergistically regulating AsA biosynthesis by upregulating the expression of GPP, GLDH, and DHAR genes. Collectively, these results demonstrate that auxin and abscisic acid antagonistically regulate AsA biosynthesis during development and drought tolerance in tomato via the SlMAPK8-SlARF4-SlMYB99/11 module. These findings provide new insights into the mechanism underlying phytohormone regulation of AsA biosynthesis and provide a theoretical basis for the future development of high AsA plants via molecular breeding.

The Bro1-like domain-containing protein, AtBro1, modulates growth and abiotic stress responses in Arabidopsis

Abscisic acid (ABA) affects plant physiology by altering gene expression, enabling plants to adapt to a wide range of environments. Plants have evolved protective mechanisms to allow seed germination in harsh conditions. Here, we explore a subset of these mechanisms involving the AtBro1 gene, which encodes one of a small family of poorly characterised Bro1-like domain-containing proteins, in Arabidopsis thaliana plants subjected to multiple abiotic stresses. AtBro1 transcripts were upregulated by salt, ABA and mannitol stress, while AtBro1-overexpression lines demonstrated robust tolerance to drought and salt stress. Furthermore, we found that ABA elicits stress-resistance responses in loss-of-function bro1-1 mutant plants and AtBro1 regulates drought resistance in Arabidopsis. When the AtBro1 promoter was fused to the β-glucuronidase (GUS) gene and introduced into plants, GUS was expressed mainly in rosette leaves and floral clusters, especially in anthers. Using a construct expressing an AtBro1-GFP fusion protein, AtBro1 was found to be localized in the plasma membrane in Arabidopsis protoplasts. A broad RNA-sequencing analysis revealed specific quantitative differences in the early transcriptional responses to ABA treatment between wild-type and loss-of-function bro1-1 mutant plants, suggesting that ABA stimulates stress-resistance responses via AtBro1. Additionally, transcripts levels of MOP9.5, MRD1, HEI10, and MIOX4 were altered in bro1-1 plants exposed to different stress conditions. Collectively, our results show that AtBro1 plays a significant role in the regulation of the plant transcriptional response to ABA and the induction of resistance responses to abiotic stress.

OsNF-YA3 regulates plant growth and osmotic stress tolerance by interacting with SLR1 and SAPK9 in rice

The antagonism between gibberellin (GA) and abscisic acid (ABA) signaling pathways is vital to balance plant growth and stress response. Nevertheless, the mechanism by which plants determine the balance remains to be elucidated. Here, we report that rice NUCLEAR FACTOR-Y A3 (OsNF-YA3) modulates GA- and ABA-mediated balance between plant growth and osmotic stress tolerance. OsNF-YA3 loss-of-function mutants exhibit stunted growth, compromised GA biosynthetic gene expression, and decreased GA levels, while its overexpression lines have promoted growth and enhanced GA content. Chromatin immunoprecipitation-quantitative polymerase chain reaction analysis and transient transcriptional regulation assays demonstrate that OsNF-YA3 activates GA biosynthetic gene OsGA20ox1 expression. Furthermore, the DELLA protein SLENDER RICE1 (SLR1) physically interacts with OsNF-YA3 and thus inhibits its transcriptional activity. On the other side, OsNF-YA3 negatively regulates plant osmotic stress tolerance by repressing ABA response. OsNF-YA3 reduces ABA levels by transcriptionally regulating ABA catabolic genes OsABA8ox1 and OsABA8ox3 by binding to their promoters. Furthermore, OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE 9 (SAPK9), the positive component in ABA signaling, interacts with OsNF-YA3 and mediates OsNF-YA3 phosphorylation, resulting in its degradation in plants. Collectively, our findings establish OsNF-YA3 as an important transcription factor that positively modulates GA-regulated plant growth and negatively controls ABA-mediated water-deficit and salt tolerance. These findings shed light on the molecular mechanism underlying the balance between the growth and stress response of the plant.

SEMI-ROLLED LEAF 10 stabilizes catalase isozyme B to regulate leaf morphology and thermotolerance in rice (Oryza sativa L.)

Plant architecture and stress tolerance play important roles in rice breeding. Specific leaf morphologies and ideal plant architecture can effectively improve both abiotic stress resistance and rice grain yield. However, the mechanism by which plants simultaneously regulate leaf morphogenesis and stress resistance remains elusive. Here, we report that SRL10, which encodes a double-stranded RNA-binding protein, regulates leaf morphology and thermotolerance in rice through alteration of microRNA biogenesis. The srl10 mutant had a semi-rolled leaf phenotype and elevated sensitivity to high temperature. SRL10 directly interacted with catalase isozyme B (CATB), and the two proteins mutually increased one other's stability to enhance hydrogen peroxide (H₂ O₂ ) scavenging, thereby contributing to thermotolerance. The natural Hap3 (AGC) type of SRL10 allele was found to be present in the majority of aus rice accessions, and was identified as a thermotolerant allele under high temperature stress in both the field and the growth chamber. Moreover, the seed-setting rate was 3.19 times higher and grain yield per plant was 1.68 times higher in near-isogenic line (NIL) carrying Hap3 allele compared to plants carrying Hap1 allele under heat stress. Collectively, these results reveal a new locus of interest and define a novel SRL10-CATB based regulatory mechanism for developing cultivars with high temperature tolerance and stable yield. Furthermore, our findings provide a theoretical basis for simultaneous breeding for plant architecture and stress resistance.

Modulation of wheat grain dormancy by introducing the recombinant abscisic acid-stimulated abscisic acid biosynthesis gene

Pre-harvest sprouting of cereals greatly reduces yield and quality of the grains. Abscisic acid (ABA) is an essential phytohormone for the induction and maintenance of seed dormancy. In this study, the ABA responsive promoter-driven ABA biosynthesis gene system was introduced to common wheat (Triticum aestivum L.) to enhance ABA production in the embryos and pre-harvest sprouting tolerance of the grains. This system consists of a wheat ABA responsive element containing Early-Methionine-labelled (EM) promoter and a sorghum 9-cis-epoxycarotenoid dioxygenase (SbNCED) gene which encodes an ABA biosynthesis rate-limiting enzyme. Twenty-three independent single-insertion lines were obtained, from which five homozygous lines showing various SbNCED expression levels were selected. Correlations were observed between SbNCED expression, ABA accumulation in the embryos and enhanced dormancy levels of the grains. The engineered wheat grains exhibited a few day-delay in germination, which should be effective in reducing pre-harvest sprouting damage. However, the increase in ABA levels in the recombinant grains was moderate, which explains why germination was not completely suppressed. Further analysis indicated a concomitant increase in the expression of the ABA catabolic enzyme gene TaABA8'OH1 and in the levels of isoleucine-conjugated jasmonic acid, implying the presence of possible negative feedback regulation in the innate system, which should be overcome for future technology development. These findings advance an understanding of the regulatory mechanisms of hormone metabolism in seeds and facilitate the development of pre-harvest sprouting tolerance in cereal grains.

Transcriptome and Proteome Analysis Revealed That Hormone and Reactive Oxygen Species Synergetically Regulate Dormancy of Introgression Line in Rice (Oryza sativa L.)

Dormancy is a complex agronomy phenotype controlled by multiple signaling and a key trait repressing pre-harvest sprouting (PHS). However, the signaling network of dormancy remains unclear. In this study, we used Zhonghua11 (ZH11) with a weak dormancy, and Introgression line (IL) with a strong dormancy to study the mechanism of hormones and reactive oxygen species (ROS) crosstalk regulating rice dormancy. The germination experiment showed that the germination rate of ZH11 was 76.86%, while that of IL was only 1.25%. Transcriptome analysis showed that there were 1658 differentially expressed genes (DEGs) between IL and ZH11, of which 577 were up-regulated and 1081 were down-regulated. Additionally, DEGs were mainly enriched in oxidoreductase activity, cell periphery, and plant hormone signal transduction pathways. Tandem mass tags (TMT) quantitative proteomics analysis showed 275 differentially expressed proteins (DEPs) between IL and ZH11, of which 176 proteins were up-regulated, 99 were down-regulated, and the DEPs were mainly enriched in the metabolic process and oxidation-reduction process. The comprehensive transcriptome and proteome analysis showed that their correlation was very low, and only 56 genes were co-expressed. Hormone content detection showed that IL had significantly lower abscisic acid (ABA) contents than the ZH11 while having significantly higher jasmonic acid (JA) contents than the ZH11. ROS content measurement showed that the hydrogen peroxide (H₂O₂) content of IL was significantly lower than the ZH11, while the production rate of superoxide anion (O₂^.-) was significantly higher than the ZH11. These results indicate that hormones and ROS crosstalk to regulate rice dormancy. In particular, this study has deepened our mechanism of ROS and JA crosstalk regulating rice dormancy and is conducive to our precise inhibition of PHS.

Identification of a key locus, qNL3.1, associated with seed germination under salt stress via a genome-wide association study in rice

Two causal OsTTL and OsSAPK1 genes of the key locus qNL3.1 significantly associated with seed germination under salt stress were identified via a genome-wide association study, which could improve rice seed germination under salt stress. Rice is a salt-sensitive crop, and its seed germination determines subsequent seedling establishment and yields. In this study, 168 accessions were investigated for the genetic control of seed germination under salt stress based on the germination rate (GR), germination index (GI), time at which 50% germination was achieved (T₅₀) and mean level (ML). Extensive natural variation in seed germination was observed among accessions under salt stress. Correlation analysis showed significantly positive correlations among GR, GI and ML and a negative correlation with T₅₀ during seed germination under salt stress. Forty-nine loci significantly associated with seed germination under salt stress were identified, and seven of these were identified in both years. By comparison, 16 loci were colocated with the previous QTLs, and the remaining 33 loci might be novel. qNL3.1, colocated with qLTG-3, was simultaneously identified with the four indices in two years and might be a key locus for seed germination under salt stress. Analysis of candidate genes showed that two genes, the similar to transthyretin-like protein OsTTL and the serine/threonine protein kinase OsSAPK1, were the causal genes of qNL3.1. Germination tests indicated that both Osttl and Ossapk1 mutants significantly reduced seed germination under salt stress compared to the wild type. Haplotype analysis showed that Hap.1 of OsTTL and Hap.1 of OsSAPK1 genes were excellent alleles, and their combination resulted in high seed germination under salt stress. Eight accessions with elite performance of seed germination under salt stress were identified, which could improve rice seed germination under salt stress.

Wheat TaSnRK2.10 phosphorylates TaERD15 and TaENO1 and confers drought tolerance when overexpressed in rice

Wheat (Triticum aestivum) is particularly susceptible to water deficit at the jointing stage of its development. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) acts as a signaling hub in the response to drought stress, but whether SnRK2 helps plants cope with water deficit via other mechanisms is largely unknown. Here, we cloned and characterized TaSnRK2.10, which was induced by multiple abiotic stresses and phytohormones. Ectopic expression of TaSnRK2.10 in rice (Oryza sativa) conferred drought tolerance, manifested by multiple improved physiological indices, including increased water content, cell membrane stability, and survival rates, as well as decreased water loss and accumulation of H2O2 and malonaldehyde. TaSnRK2.10 interacted with and phosphorylated early responsive to dehydration 15 (TaERD15) and enolase 1 (TaENO1) in vivo and in vitro. TaERD15 phosphorylated by TaSnRK2.10 was prone to degradation by the 26S proteasome, thereby mitigating its negative effects on drought tolerance. Phosphorylation of TaENO1 by TaSnRK2.10 may account for the substantially increased levels of phosphoenolpyruvate (PEP), a key metabolite of primary and secondary metabolism, in TaSnRK2.10-overexpressing rice, thereby enhancing its viability under drought stress. Our results demonstrate that TaSnRK2.10 not only regulated stomatal aperture and the expression of drought-responsive genes, but also enhanced PEP supply and promoted the degradation of TaERD15, all of which enhanced drought tolerance.

ZmEREB92 interacts with ZmMYC2 to activate maize terpenoid phytoalexin biosynthesis upon Fusarium graminearum infection through jasmonic acid/ethylene signaling

Maize (Zea mays) terpenoid phytoalexins (MTPs) induced by multiple fungi display extensive antimicrobial activities, yet how maize precisely regulates MTP accumulation upon pathogen infection remains elusive. In this study, pretreatment with jasmonic acid (JA)/ethylene (ET)-related inhibitors significantly reduced Fusarium graminearum-induced MTP accumulation and resulted in enhanced susceptibility to F. graminearum, indicating the involvement of JA/ET in MTP regulatory network. ZmEREB92 positively regulated MTP biosynthetic gene (MBG) expression by correlation analysis. Knockout of ZmEREB92 significantly compromised maize resistance to F. graminearum with delayed induction of MBGs and attenuated MTP accumulation. The activation of ZmEREB92 on MBGs is dependent on the interaction with ZmMYC2, which directly binds to MBG promoters. ZmJAZ14 interacts both with ZmEREB92 and with ZmMYC2 in a competitive manner to negatively regulate MBG expression. Altogether, our findings illustrate the regulatory mechanism for JA/ET-mediated MTP accumulation upon F. graminearum infection with the involvement of ZmEREB92, ZmMYC2, and ZmJAZ14, which provides new insights into maize disease responses.

Molecular characterization reveals that OsSAPK3 improves drought tolerance and grain yield in rice

BACKGROUND

Many data suggest that the sucrose non-fermenting 1-related kinases 2 (SnRK2s) are very important to abiotic stress for plants. In rice, these kinases are known as osmotic stress/ABA-activated protein kinases (SAPKs). Osmotic stress/ABA-activated protein kinase 3 (OsSAPK3) is a member of SnRK2II in rice, but its function is still unclear.

RESULTS

The expression of OsSAPK3 was up regulated by drought, NaCl, PEG and ABA. OsSAPK3 mutated seedings (sapk3-1 and sapk3-2) showed reduced hypersensitivity to exogenous ABA. In addition, under drought conditions, sapk3-1 and sapk3-2 showed more intolerance to drought, including decreased survival rate, increased water loss rate, increased stomatal conductance and significantly decreased expression levels of SLAC1 and SLAC7. Physiological and metabolic analyses showed that OsSAPK3 might play an important role in drought stress signaling pathway by affecting osmotic adjustment and osmolytes, ROS detoxification and expression of ABA dependent and independent dehydration-responsive genes. All gronomic traits analyses demonstrated that OsSAPK3 could improve rice yield by affecting the regulation of tiller numbers and grain size.

CONCLUSION

OsSAPK3 plays an important role in both ABA-dependent and ABA-independent drought stress responses. More interestingly, OsSAPK3 could improve rice yield by indirectly regulating tiller number and grain size. These findings provide new insight for the development of drought-resistant rice.

TcbZIP60 positively regulates pyrethrins biosynthesis in Tanacetum cinerariifolium

Pyrethrins, synthesized in the perennial plant Tanacetum cinerariifolium, are a class of terpene mixtures with high insecticidal activity and low human toxicity, which are widely used in plant-derived pesticides. Numerous studies have identified multiple pyrethrins biosynthesis enzymes, which can be enhanced by exogenous hormones such as methyl jasmonate (MeJA). However, the mechanism by which hormone signaling regulates pyrethrins biosynthesis and the potential involvement of certain transcription factors (TFs) remain unclear. In this study, we found that the expression level of a TF in T. cinerariifolium was significantly increased after treatment with plant hormones (MeJA, abscisic acid). Subsequent analysis identified this TF as a member of the basic region/leucine zipper (bZIP) family and was thus named TcbZIP60. TcbZIP60 was localized in the nucleus, suggesting that it is involved in the transcription process. The expression profiles of TcbZIP60 were similar to those of pyrethrins synthesis genes in different flower organs and at different flowering stages. Furthermore, TcbZIP60 could directly bind to the E-box/G-box motifs in the promoters of the pyrethrins synthesis genes TcCHS and TcAOC to activate their expression. Transient overexpression of TcbZIP60 increased the expression levels of pyrethrins biosynthesis genes, leading to the significant accumulation of pyrethrins. Silencing of TcbZIP60 significantly downregulated pyrethrins accumulation and the expression of related genes. Overall, our results reveal a novel TF, TcbZIP60, that regulates both the terpenoid and jasmonic acid pathways of pyrethrins biosynthesis in T. cinerariifolium.

9-cis-epoxycarotenoid dioxygenase 1 confers heat stress tolerance in rice seedling plants

High temperature is one of the main constraints affecting plant growth and development. It has been reported that abscisic acid (ABA) synthesis gene 9-cis-epoxycarotenoid dioxygenase (NCED) positively regulates plant resistance to salt, cold, and drought stresses. However, little is known about the function of the NCED gene in heat tolerance of rice. Here, we found that OsNCED1 was a heat stress inducible gene. Rice seedlings overexpressing OsNCED1 showed enhanced heat tolerance with more abundant ABA content, whereas the knockout mutant osnced1 accumulated less ABA and showed more sensitive to heat stress. Under heat stress, increased expression of OsNCED1 could reduce membrane damage and reactive oxygen species (ROS) level of plants, and elevate the activity of antioxidant enzymes. Moreover, real time-quantitative PCR (RT-qPCR) analysis showed that overexpression of OsNCED1 significantly activated the expression of genes involved in antioxidant enzymes, ABA signaling pathway, heat response, and defense. Together, our results indicate that OsNCED1 positively regulates heat tolerance of rice seedling by raising endogenous ABA contents, which leads to the improved antioxidant capacity and activated expression of heat and ABA related genes.

Identification and expression pattern analysis of the OsSnRK2 gene family in rice

Sucrose non-fermenting-1-related protein kinase 2 (SnRK2) is a class of plant-specific serine/threonine (Ser/Thr) protein kinase that plays an important role in rice stress tolerance, growth and development. However, systematic bioinformatics and expression pattern analysis have not been reported. In the current study, ten OsSnRK2 genes were identified in the rice genome and located on 7 chromosomes, which can be classified into three subfamilies (I, II, and III). Many cis-regulatory elements were identified in the promoter region of OsSnRK2 genes, including hormone response elements, defense and stress responsive elements, indicating that the OsSnRK2 family may play a crucial role in response to hormonal and abiotic stress. Quantitative tissue analysis showed that OsSnRK2 genes expressed in all tissues of rice, but the expression abundance varied from different tissues and showed varietal variability. In addition, expression pattern of OsSnRK2 were analyzed under abiotic stress (salt, drought, salt and drought) and showed obvious difference in diverse abiotic stress. In general, these results provide useful information for understanding the OsSnRK2 gene family and analyzing its functions in rice in response to ABA, salt and drought stress, especially salt-drought combined stress.

DELAY OF GERMINATION 1, the Master Regulator of Seed Dormancy, Integrates the Regulatory Network of Phytohormones at the Transcriptional Level to Control Seed Dormancy

Seed dormancy, an important adaptive trait that governs germination timing, is endogenously controlled by phytohormones and genetic factors. DELAY OF GERMINATION 1 (DOG1) is the vital genetic regulator of dormancy, significantly affecting the expression of numerous ABA and GA metabolic genes. However, whether DOG1 could influence the expression of other phytohormone-related genes is still unknown. Here, we comprehensively investigated all well-documented hormone-related genes which might be affected in dog1-2 dry or imbibed seeds by using whole-transcriptome sequencing (RNA-seq). We found that DOG1 could systematically control the expression of phytohormone-related genes. An evident decrease was observed in the endogenous signal intensity of abscisic acid (ABA) and indole-3-acetic acid (IAA), while a dramatic increase appeared in that of gibberellins (GA), brassinosteroids (BR), and cytokinin (CK) in the dog1-2 background, which may contribute considerably to its dormancy-deficient phenotype. Collectively, our data highlight the role of DOG1 in balancing the expression of phytohormone-related genes and provide inspirational evidence that DOG1 may integrate the phytohormones network to control seed dormancy.

Rice OsPUB16 modulates the 'SAPK9-OsMADS23-OsAOC' pathway to reduce plant water-deficit tolerance by repressing ABA and JA biosynthesis

Ubiquitin-mediated proteolysis plays crucial roles in plant responses to environmental stress. However, the mechanism by which E3 ubiquitin ligases modulate plant stress response still needs to be elucidated. In this study, we found that rice PLANT U-BOX PROTEIN 16 (OsPUB16), a U-box E3 ubiquitin ligase, negatively regulates rice drought response. Loss-of-function mutants of OsPUB16 generated through CRISPR/Cas9 system exhibited the markedly enhanced water-deficit tolerance, while OsPUB16 overexpression lines were hypersensitive to water deficit stress. Moreover, OsPUB16 negatively regulated ABA and JA response, and ospub16 mutants produced more endogenous ABA and JA than wild type when exposed to water deficit. Mechanistic investigations revealed that OsPUB16 mediated the ubiquitination and degradation of OsMADS23, which is the substrate of OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE 9 (SAPK9) and increases rice drought tolerance by promoting ABA biosynthesis. Further, the ChIP-qPCR analysis and transient transactivation activity assays demonstrated that OsMADS23 activated the expression of JA-biosynthetic gene OsAOC by binding to its promoter. Interestingly, SAPK9-mediated phosphorylation on OsMADS23 reduced its ubiquitination level by interfering with the OsPUB16-OsMADS23 interaction, which thus enhanced OsMADS23 stability and promoted OsAOC expression. Collectively, our findings establish that OsPUB16 reduces plant water-deficit tolerance by modulating the 'SAPK9-OsMADS23-OsAOC' pathway to repress ABA and JA biosynthesis.

TcJAV3-TcWRKY26 Cascade Is a Missing Link in the Jasmonate-Activated Expression of Taxol Biosynthesis Gene DBAT in Taxus chinensis

Jasmonates (JAs) are the most effective inducers for the biosynthesis of various secondary metabolites. Currently, jasmonate ZIM domain (JAZ) and its interactors, such as MYC2, constitute the main JA signal transduction cascade, and such a cascade fails to directly regulate all the taxol biosynthesis genes, especially the rate-limit gene, DBAT. Another JA signaling branch, JAV and WRKY, would probably fill the gap. Here, TcJAV3 was the closest VQ-motif-containing protein in Taxus chinensis to AtJAV1. Although TcJAV3 was overexpressed in AtJAV1 knockdown mutant, JAVRi17, the enhanced disease resistance to Botrytis cinerea caused by silencing AtJAV1 was completely recovered. The results indicated that TcJAV3 indeed transduced JA signal as AtJAV1. Subsequently, TcWRKY26 was screened out to physically interact with TcJAV3 by using a yeast two-hybrid system. Furthermore, bimolecular fluorescence complementation and luciferase complementary imaging also confirmed that TcJAV3 and TcWRKY26 could form a protein complex in vivo. Our previous reports showed that transient TcWRKY26 overexpression could remarkably increase DBAT expression. Yeast one-hybrid and luciferase activity assays revealed that TcWRKY26 could directly bind with the wa-box of the DBAT promoter to activate downstream reporter genes. All of these results indicated that TcWRKY26 acts as a direct regulator of DBAT, and the TcJAV3−TcWRKY26 complex is actually another JA signal transduction mode that effectively regulates taxol biosynthesis in Taxus. Our results revealed that JAV−WRKY complexes directly regulated DBAT gene in response to JA stimuli, providing a novel model for JA-regulated secondary metabolism. Moreover, JAV could also transduce JA signal and function non-redundantly with JAZ during the regulation of secondary metabolisms.

Auxin and abscisic acid antagonistically regulate ascorbic acid production via the SlMAPK8-SlARF4-SlMYB11 module in tomato

Ascorbic acid (AsA) is a multifunctional phytonutrient that is essential for the human diet as well as plant development. While much is known about AsA biosynthesis in plants, how this process is regulated in tomato (Solanum lycopersicum) fruits remains unclear. Here, we found that auxin treatment inhibited AsA accumulation in the leaves and pericarps of tomato. The auxin response factor gene SlARF4 is induced by auxin to mediate auxin-induced inhibition of AsA accumulation. Specifically, SlARF4 transcriptionally inhibits the transcription factor gene SlMYB11, thereby modulating AsA accumulation by regulating the transcription of the AsA biosynthesis genes l-galactose-1-phosphate phosphatase, l-galactono-1,4-lactone dehydrogenase, and dehydroascorbate. By contrast, abscisic acid (ABA) treatment increased AsA accumulation in tomato under drought stress. ABA induced the expression of the mitogen-activated protein kinase gene SlMAPK8. We demonstrate that SlMAPK8 phosphorylates SlARF4 and inhibits its transcriptional activity, whereas SlMAPK8 phosphorylates SlMYB11 and activates its transcriptional activity. SlMAPK8 functions in ABA-induced AsA accumulation and drought stress tolerance. Moreover, ABA antagonizes the effects of auxin on AsA biosynthesis. Therefore, auxin- and ABA-induced regulation of AsA accumulation is mediated by the SlMAPK8-SlARF4-SlMYB11 module in tomato during fruit development and drought stress responses, shedding light on the roles of phytohormones in regulating AsA accumulation to mediate stress tolerance.

Comparison of anther transcriptomes in response to cold stress at the reproductive stage between susceptible and resistant Japonica rice varieties

BACKGROUND

Rice is one of the most important cereal crops in the world but is susceptible to cold stress (CS). In this study, we carried out parallel transcriptomic analysis at the reproductive stage on the anthers of two Japonica rice varieties with contrasting CS resistance: cold susceptible Longjing11 (LJ11) and cold resistant Longjing25 (LJ25).

RESULTS

According to the obtained results, a total of 16,762 differentially expressed genes (DEGs) were identified under CS, including 7,050 and 14,531 DEGs in LJ25 and LJ11, respectively. Examining gene ontology (GO) enrichment identified 35 up- and 39 down-regulated biological process BP GO terms were significantly enriched in the two varieties, with 'response to heat' and 'response to cold' being the most enriched. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified 33 significantly enriched pathways. Only the carbon metabolism and amino acid biosynthesis pathways with down-regulated DEGs were enriched considerably in LJ11, while the plant hormone signal transduction pathway (containing 153 DEGs) was dramatically improved. Eight kinds of plant hormones were detected in the pathway, while auxin, abscisic acid (ABA), salicylic acid (SA), and ethylene (ETH) signaling pathways were found to be the top four pathways with the most DEGs. Furthermore, the protein-protein interaction (PPI) network analysis identified ten hub genes (co-expressed gene number ≥ 30), including six ABA-related genes. Various DEGs (such as OsDREB1A, OsICE1, OsMYB2, OsABF1, OsbZIP23, OsCATC, and so on) revealed distinct expression patterns among rice types when the DEGs between LJ11 and LJ25 were compared, indicating that they are likely responsible for CS resistance of rice in cold region.

CONCLUSION

Collectively, our findings provide comprehensive insights into complex molecular mechanisms of CS response and can aid in CS resistant molecular breeding of rice in cold regions.

Rice protein phosphatase 1 regulatory subunits OsINH2 and OsINH3 participate actively in growth and adaptive responses under abscisic acid

Rice (Oryza sativa L.), a worldwide staple food crop, is affected by various environmental stressors that ultimately reduce yield. However, diversified physiological and molecular responses enable it to cope with adverse factors. It includes the integration of numerous signaling in which protein phosphatase 1 (PP1) plays a pivotal role. Research on PP1 has been mostly limited to the PP1 catalytic subunit in numerous cellular progressions. Therefore, we focused on the role of PP1 regulatory subunits (PP1r), OsINH2 and OsINH3, homologs of AtINH2 and AtINH3 in Arabidopsis, in rice growth and stress adaptations. Our observations revealed that these are ubiquitously expressed regulatory subunits that interacted and colocalized with their counter partners, type 1 protein phosphatase (OsTOPPs) but could not change their subcellular localization. The mutation in OsINH2 and OsINH3 reduced pollen viability, thereby affected rice fertility. They were involved in abscisic acid (ABA)-mediated inhibition of seed germination, perhaps by interacting with osmotic stress/ABA-activated protein kinases (OsSAPKs). Meanwhile, they positively participated in osmotic adjustment by proline biosynthesis, detoxifying reactive oxygen species (ROS) through peroxidases (POD), reducing malondialdehyde formation (MDA), and regulating stress-responsive genes. Moreover, their co-interaction proposed they might mediate cellular processes together or by co-regulation; however, the special behavior of two different PP1r is needed to explore. In a nutshell, this research enlightened the involvement of OsINH2 and OsINH3 in the reproductive growth of rice and adaptive strategies under stress. Hence, their genetic interaction with ABA components and deep mechanisms underlying osmotic regulation and ROS adjustment would explain their role in complex signaling. This research offers the basis for introducing stress-resistant crops.

Panicle Apical Abortion 7 Regulates Panicle Development in Rice (Oryza sativa L.)

The number of grains per panicle significantly contributes to rice yield, but the regulatory mechanism remains largely unknown. Here, we reported a loss-of-function mutant, panicle apical abortion 7 (paa7), which exhibited panicle abortion and degeneration of spikelets on the apical panicles during the late stage of young panicle development in rice. High accumulations of H₂O₂ in paa7 caused programmed cell death (PCD) accompanied by nuclear DNA fragmentation in the apical spikelets. Map-based cloning revealed that the 3 bp "AGC" insertion and 4 bp "TCTC" deletion mutation of paa7 were located in the 3'-UTR regions of LOC_Os07g47330, which was confirmed through complementary assays and overexpressed lines. Interestingly, LOC_Os07g47330 is known as FRIZZY PANICLE (FZP). Thus, PAA7 could be a novel allele of FZP. Moreover, the severe damage for panicle phenotype in paa7/lax2 double mutant indicated that PAA7 could crosstalk with Lax Panicle 2 (LAX2). These findings suggest that PAA7 regulates the development of apical spikelets and interacts with LAX2 to regulate panicle development in rice.

Jasmonates in plant growth and development and elicitation of secondary metabolites: An updated overview

Secondary metabolites are incontestably key specialized molecules with proven health-promoting effects on human beings. Naturally synthesized secondary metabolites are considered an important source of pharmaceuticals, food additives, cosmetics, flavors, etc., Therefore, enhancing the biosynthesis of these relevant metabolites by maintaining natural authenticity is getting more attention. The application of exogenous jasmonates (JAs) is well recognized for its ability to trigger plant growth and development. JAs have a large spectrum of action that covers seed germination, hypocotyl growth regulation, root elongation, petal expansion, and apical hook growth. This hormone is considered as one of the key regulators of the plant's growth and development when the plant is under biotic or abiotic stress. The JAs regulate signal transduction through cross-talking with other genes in plants and thereby deploy an appropriate metabolism in the normal or stressed conditions. It has also been found to be an effective chemical elicitor for the synthesis of naturally occurring secondary metabolites. This review discusses the significance of JAs in the growth and development of plants and the successful outcomes of jasmonate-driven elicitation of secondary metabolites including flavonoids, anthraquinones, anthocyanin, xanthonoid, and more from various plant species. However, as the enhancement of these metabolites is essentially measured via in vitro cell culture or foliar spray, the large-scale production is significantly limited. Recent advancements in the plant cell culture technology lay the possibilities for the large-scale manufacturing of plant-derived secondary metabolites. With the insights about the genetic background of the metabolite biosynthetic pathway, synthetic biology also appears to be a potential avenue for accelerating their production. This review, therefore, also discussed the potential manoeuvres that can be deployed to synthesis plant secondary metabolites at the large-scale using plant cell, tissue, and organ cultures.

Understanding of Hormonal Regulation in Rice Seed Germination

Seed germination is a critical stage during the life cycle of plants. It is well known that germination is regulated by a series of internal and external factors, especially plant hormones. In Arabidopsis, many germination-related factors have been identified, while in rice, the important crop and monocot model species and the further molecular mechanisms and regulatory networks controlling germination still need to be elucidated. Hormonal signals, especially those of abscisic acid (ABA) and gibberellin (GA), play a dominant role in determining whether a seed germinates or not. The balance between the content and sensitivity of these two hormones is the key to the regulation of germination. In this review, we present the foundational knowledge of ABA and GA pathways obtained from germination research in Arabidopsis. Then, we highlight the current advances in the identification of the regulatory genes involved in ABA- or GA-mediated germination in rice. Furthermore, other plant hormones regulate seed germination, most likely by participating in the ABA or GA pathways. Finally, the results from some regulatory layers, including transcription factors, post-transcriptional regulations, and reactive oxygen species, are also discussed. This review aims to summarize our current understanding of the complex molecular networks involving the key roles of plant hormones in regulating the seed germination of rice.

OsNAC016 regulates plant architecture and drought tolerance by interacting with the kinases GSK2 and SAPK8

Ideal plant architecture and drought tolerance are important determinants of yield potential in rice (Oryza sativa). Here, we found that OsNAC016, a rice NAC (NAM, ATAF, and CUC) transcription factor, functions as a regulator in the crosslink between brassinosteroid (BR)-mediated plant architecture and abscisic acid (ABA)-regulated drought responses. The loss-of-function mutant osnac016 exhibited erect leaves and shortened internodes, but OsNAC016-overexpressing plants had opposite phenotypes. Further investigation revealed that OsNAC016 regulated the expression of the BR biosynthesis gene D2 by binding to its promoter. Moreover, OsNAC016 interacted with and was phosphorylated by GSK3/SHAGGY-LIKE KINASE2 (GSK2), a negative regulator in the BR pathway. Meanwhile, the mutant osnac016 had improved drought stress tolerance, supported by a decreased water loss rate and enhanced stomatal closure in response to exogenous ABA, but OsNAC016-overexpressing plants showed attenuated drought tolerance and reduced ABA sensitivity. Further, OSMOTIC STRESS/ABA-ACTIVATED PROTEIN KINASE8 (SAPK8) phosphorylated OsNAC016 and reduced its stability. The ubiquitin/26S proteasome system is an important degradation pathway of OsNAC016 via the interaction with PLANT U-BOX PROTEIN43 (OsPUB43) that mediates the ubiquitination of OsNAC016. Notably, RNA-sequencing analysis revealed global roles of OsNAC016 in promoting BR-mediated gene expression and repressing ABA-dependent drought-responsive gene expression, which was confirmed by chromatin immunoprecipitation quantitative PCR analysis. Our findings establish that OsNAC016 is positively involved in BR-regulated rice architecture, negatively modulates ABA-mediated drought tolerance, and is regulated by GSK2, SAPK8, and OsPUB43 through posttranslational modification. Our data provide insights into how plants balance growth and survival by coordinately regulating the growth-promoting signaling pathway and response under abiotic stresses.