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Enhancing stalk strength is a crucial strategy to reduce lodging. We identified a maize inbred line, QY1, with superior stalk mechanical strength. Comprehensive analyses of the microstructure, cell wall composition, and transcriptome of QY1 were performed to elucidate the underlying factors contributing to its increased strength. Notably, both the vascular bundle area and the thickness of the sclerenchyma cell walls in QY1 were significantly increased. Furthermore, analyses of cell wall components revealed a significant increase in cellulose content and a notable reduction in lignin content. RNA sequencing (RNA-seq) revealed changes in the expression of numerous genes involved in cell wall synthesis and modification, especially those encoding pectin methylesterase (PME). Variations in PME activity and the degree of methylesterification were noted. Additionally, glycolytic efficiency in QY1 was significantly enhanced. These findings indicate that QY1 could be a valuable resource for the development of maize varieties with enhanced stalk mechanical strength and for biofuel production. [ABSTRACT FROM AUTHOR]

SUMMARY: Heat stress is an environmental factor that significantly threatens crop production worldwide. Nevertheless, the molecular mechanisms governing plant responses to heat stress are not fully understood. Plant zinc finger CCCH proteins have roles in stress responses as well as growth and development through protein–RNA, protein–DNA, and protein–protein interactions. Here, we reveal an integrated multi‐level regulation of plant thermotolerance that is mediated by the CCCH protein C3H15 in Arabidopsis. Heat stress rapidly suppressed C3H15 transcription, which attenuated C3H15‐inhibited expression of its target gene HEAT SHOCK TRANSCRIPTION FACTOR A2 (HSFA2), a central regulator of heat stress response (HSR), thereby activating HEAT SHOCK COGNATE 70 (HSC70.3) expression. The RING‐type E3 ligase MED25‐BINDING RING‐H2 PROTEIN 2 (MBR2) was identified as an interacting partner of C3H15. The mbr2 mutant was susceptible to heat stress compared to wild‐type plants, whereas plants overexpressing MBR2 showed increased heat tolerance. MBR2‐dependent ubiquitination mediated the degradation of phosphorylated C3H15 protein in the cytoplasm, which was enhanced by heat stress. Consistently, heat sensitivities of C3H15 overexpression lines increased in MBR2 loss‐of‐function and decreased in MBR2 overexpression backgrounds. Heat stress‐induced accumulation of HSC70.3 promoted MBR2‐mediated degradation of C3H15 protein, implying that an auto‐regulatory loop involving C3H15, HSFA2, and HSC70.3 regulates HSR. Heat stress also led to the accumulation of C3H15 in stress granules (SGs), a kind of cytoplasmic RNA granule. This study advances our understanding of the mechanisms plants use to respond to heat stress, which will facilitate technologies to improve thermotolerance in crops. Significance Statement: Heat stress is a severe environmental factor that significantly inhibits plant growth and development, but the molecular mechanisms governing plant responses to heat stress are not fully understood. This study reveals a mechanism of multi‐level regulation for thermotolerance in Arabidopsis, which will facilitate creating heat‐tolerant crops. [ABSTRACT FROM AUTHOR]

Summary: Tree peony (Paeonia suffruticosa) undergoes bud endodormancy, and gibberellin (GA) pathway plays a crucial role in dormancy regulation. Recently, a key DELLA protein PsRGL1 has been identified as a negative regulator of bud dormancy release. However, the mechanism of GA signal to break bud dormancy remains unknown.In this study, yeast two‐hybrid screened PsSOC1 interacting with PsRGL1 through its MADS domain, and interaction was identified using pull‐down and luciferase complementation imaging assays Transformation in tree peony and hybrid poplar confirmed that PsSOC1 facilitated bud dormancy release. Transcriptome analysis of PsSOC1‐overexpressed buds indicated PsCYCD3.3 and PsEBB3 were its potential downstream targets combining with promoter survey, and they also accelerated bud dormancy release verified by genetic analysis.Yeast one‐hybrid, electrophoretic mobility shifts assays, chromatin immunoprecipitation quantitative PCR, and dual luciferase assays confirmed that PsSOC1 could directly bind to the CArG motif of PsCYCD3.3 and PsEBB3 promoters via its MADS domain. PsRGL1–PsSOC1 interaction inhibited the DNA‐binding activity of PsSOC1. Additionally, PsCYCD3.3 promoted bud dormancy release by rebooting cell proliferation.These findings elucidated a novel GA pathway, GA‐PsRGL1‐PsSOC1‐PsCYCDs, which expanded our understanding of the GA pathway in bud dormancy release. [ABSTRACT FROM AUTHOR]