The TDIF-PXY signaling module is best known for its role in vascular development, a process closely linked to phloem function and long-distance sugar transport. However, the molecular mechanisms by which TDIF-PXY-mediated vascular development links phloem sugar transport and signaling to leaf senescence remain largely unclear. Here, we show that Arabidopsis TDIF-PXY-defective mutants exhibit accelerated leaf senescence, accompanied by impaired phloem transport and increased vein callose deposition, together with transcriptional reprogramming of sugar metabolism and carbohydrate accumulation. Inducible PXY knockdown further suggests that changes in sugar metabolism-related gene expression associated with TDIF-PXY attenuation arise primarily from impaired phloem transport rather than from a direct transcriptional output of this pathway. Genetic and metabolic analyses identify trehalose-6-phosphate (T6P) as a key signal contributing to the premature senescence of the pxy mutant. Mechanistically, the T6P-inhibited SnRK1 catalytic subunit KIN10 directly interacts with and phosphorylates the senescence regulator ORE1 at S115, promoting ORE1 destabilization. Elevated T6P inhibits KIN10 activity, thereby reducing S115-dependent ORE1 phosphorylation and stabilizing ORE1. During natural leaf aging, the expression of TDIF-PXY pathway genes and phloem transport capacity decline, whereas T6P accumulation and vein callose deposition increase. Maintaining TDIF expression in phloem tissues preserves phloem transport and delays senescence. Together, these findings reveal a T6P-KIN10-ORE1 regulatory axis that links vascular function to leaf aging, supporting the idea that vascular status serves as an intrinsic cue for the onset of leaf senescence.
Junjie Liu, Yong-Lin Lv, Zhenpei Pang et al.· Plant Communications· 0 citations
Plant development and stress responses are coordinated through phytohormone-mediated gene networks, yet resolving their spatiotemporal crosstalk remains challenging. Here, we generate a single-nucleus transcriptomic atlas of Arabidopsis seedlings, capturing early (0.5 h, 3 h) responses to 9 hormones across ~500,000 nuclei, including auxin, cytokinin, ABA, gibberellin, strigolactone, brassinosteroid, ethylene, JA, and SA. Within this window, most hormones showed rapid and cell-type-specific responses, whereas JA, SA, ABA showed more sustained and convergent responses by 3 h. Co-directional transcriptomic overlap was strongest at 0.5 h, while the JA-, SA-, and ABA-related responses showed the highest overlap at 3 h. Pathway-level analysis indicated asymmetric relationships among JA, SA, and ABA across biosynthetic and catabolic layers. Spatially, transcriptomic response overlap separated shoots from other tissues, with guard cells as shoot-side outliers showing weak JA–SA–ABA overlap. We further identified an SA-induced guard-cell-specific MYB60-centered module linked to ABA-associated stomatal regulators, suggesting a circuit that may fine-tune stomatal dynamics. Together, this atlas provides a high-resolution view of phytohormone response dynamics and interactions. Here the authors describe cell-type-specific responses of Arabidopsis seedlings to nine phytohormones. They characterize transcriptional crosstalk among them, and identify a guard-cell MYB60 module linked to stomatal regulation.
Zhijian Liu, Zhuowen Li, Yuzhuo Wang et al.· Nature Communications· 0 citations
The roles and molecular mechanisms of diverse RNA types, the roles of RNA structures and modifications in regulatory processes, and the translational application of RNA-based strategies for improving agronomic traits are discussed.
Yijun Qi, Yue-Qin Chen, Hongwei Guo et al.· Science China Life Sciences· 0 citations