TL;DR
The function of GmDREB1D as a transcriptional regulator in growth is revealed and it is revealed that GmDREB1D activates the expression of GmGA2ox8, which triggers the inactivation of GAs and reduces GA response to limit plant height.
The GmSNAT1 gene, which encodes a key enzyme involved in soybean melatonin biosynthesis, is crucial for abiotic stress tolerance. In the present study, the molecular mechanism by which GmSNAT1 enhances cold tolerance is elucidated. The cold tolerance of plants was significantly increased by GmSNAT1 overexpression and reduced by CRISPR/Cas9-mediated knockout, a phenotype that was effectively rescued by exogenous melatonin. Integrated transcriptomic, physiological, and biochemical analyses revealed that the GmSNAT1-mediated melatonin pathway activates calcium signaling; coordinates the crosstalk between auxin, abscisic acid, and ethylene; and mobilizes transcription factor networks to orchestrate bidirectional physiological responses. Additionally, the activation of antioxidant systems for reactive oxygen species scavenging and the upregulation of photosynthesis-related genes to maintain photosynthetic stability were explored. The physical interaction between GmSNAT1 and the plant sulfotyrosine peptide receptor GmPSYR1 was confirmed using co-immunoprecipitation, bimolecular fluorescence complementation, and yeast two-hybrid assays. This interaction may be involved in cold stress signal transduction, regulation of root development, and redox homeostasis through GmPSYR1. Collectively, these findings demonstrate that cold adaptation in soybeans is synergistically enhanced by GmSNAT1 via a multidimensional axis encompassing melatonin synthesis, signal transduction, and physiological protection, thereby providing a novel molecular target for breeding cold-tolerant crops.
Soybean (Glycine max (L.) Merr.) was originally domesticated in China and is a kind of significant leguminous crop, which can fix atmospheric nitrogen to bioavailable nitrogen in association with rhizobia. Ceramides, intermediates of sphingolipids, are crucial structural components in membrane formation and also function as signaling molecules, which play crucial roles in plant development and defense. Although Arabidopsis ceramide synthase genes AtLOH1 and AtLOH3 overexpression plants increased biomass compared to the wild type, the potential mechanism in plant growth was still unclear. A soybean ceramide synthase gene 1 (GmCS1) has a high expression level in the stem, and the protein is localized in the endoplasmic reticulum. Overexpression of GmCS1 promotes soybean lateral branch development for effective branch formation, significantly increasing the number of lateral branches and pods. Using transcriptomic profiles, we found that GmCS1 overexpression lines displayed the upregulation of plant hormone signal transduction pathway gene expression in developmental branches. Actually, Indole-3-acetic acid (IAA) induces bud outgrowth rather than initiation according to the determination of endogenous IAA and cytokinin (CKs) in soybean lateral branches. Collectively, these results suggest that GmCS1 may be a functional ceramide synthase gene in soybean, with the GmCS1-mediated regulatory network playing a crucial role in controlling branch development by IAA and CKs homeostasis. Exploring the regulation mechanisms by GmCS1 overexpression lines is essential for Ideal Soybean Architecture (ISA) innovation.
Soil inorganic nitrogen (N) availability is a critical determinant of symbiotic nitrogen fixation efficiency, making it essential for legumes to respond appropriately and effectively to N fluctuations. Here, we identify a pair of high N response factors GmNIGT2a/2b (NITRATE-INDUCIBLE GARP-TYPE TRANSCRIPTIONAL REPRESSOR). GmNIGT2a/2b are activated by GmNLP4a/b (NIN-like proteins) under high N. The nodules of gmnigt2a/2b double mutants exhibit exacerbated reduction in nitrogenase activity and accelerated senescence in response to high N. Integration of RNA-seq and DAP-seq analyses reveals that GmNIGT2a/2b negatively regulate a suite of core N-induced genes, including NAC, WRKY, and bZIP transcription factors as well as trehalose metabolism genes. GmNIGT2b binds to the promoters of SNAP3 and NAC039 and represses their expression, thereby delaying nodule senescence. Our results suggest that GmNIGT2a/2b-mediated transcriptional regulation prevents excessive nodule senescence in response to high N, highlighting the complexity of transcriptional reprogramming for environmental adaptation in nodules.
AP2/ERF (APETALA2/ethylene-responsive factor) represents one of the largest transcription factor superfamilies in plants, playing crucial roles in regulating plant growth and development as well as responding to abiotic stresses. Investigating the functions of maize (Zea mays L.) AP2/ERF family genes will provide novel genetic resources for maize genetic improvement. In this study, the AP2/ERF transcription factor superfamily member ZmEREB54 (GRMZM2G020054, Gene ID: 100,278,463) was cloned from maize and was systematically analyzed functionally. The full-length CDS of ZmEREB54 gene was 561 bp, encoding 186 amino acids with a typical AP2/ERF conserved domain. Its promoter region contained cis-acting elements associated with responses to various abiotic stresses and hormones. Maize expression pattern analysis revealed that ZmEREB54 was highly expressed in V12 roots, with significant expression changes under osmotic stress, drought, high salinity, and treatments with abscisic acid (ABA) and jasmonic acid (JA). Phenotypic analysis showed that transgenic Arabidopsis thaliana over-expressing ZmEREB54 exhibited significantly longer roots compared to wild-type plants under high salinity, drought, osmotic stress, and hormone treatments (JA, ABA). Stress-responsive marker genes RD29A and RD22 were upregulated in the transgenic A. thaliana lines. The significantly decreased malondialdehyde (MDA) accumulation and markedly increased peroxidase (POD) activity in transgenic A. thaliana further demonstrate the improvement of its stress tolerance. Yeast two-hybrid (Y2H) assays revealed an interaction between ZmEREB54 and ZmMADS24.6, suggesting potential cooperative regulation of ZmEREB54 and ZmMADS24.6 in maize root development and stress responses. This study establishes a solid foundation for further clarifying the biological functions and molecular mechanisms of ZmEREB54 in regulating maize root growth and development, as well as responding to drought and salt stresses.
Plants detect neighbours through a reduced red-to-far-red ratio (R:FR), triggering elongation growth that reduces crop yield. Although Gibberellin (GA) is required for the neighbour-proximity (NP) elongation response, bioactive GA levels do not increase sufficiently to account for elongation magnitude, suggesting GA sensitivity as an additional regulated variable. Here, we show that GID1C, one of three Arabidopsis GA receptors, is the primary GA receptor involved in NP-induced elongation. GID1C protein accumulates selectively in hypocotyls and root tips under low R:FR without an increase in bioactive GA. The gid1c mutant shows a reduced elongation response that exogenous GA treatment cannot rescue. Transcriptome profiling reveals that GID1C controls 86% of the NP-responsive transcriptome, including genes for cell growth, division, and transcriptional regulation. Hub analysis identifies ICE1 as a GID1C-repressed transcriptional brake. ICE1 transcript is suppressed under low R:FR in a GID1C-dependent manner, and a phosphorylation-resistant ICE1 allele blocks NP-induced elongation. Together, these findings establish GA perception as an additional regulatory layer in NP, with subfunctionalisation among GID1 paralogs shaping the response to neighbouring plants.