T6P-KIN10-ORE1调控轴在TDIF-PXY信号传导的下游起作用，将拟南芥韧皮部糖转运与叶片衰老联系起来
The T6P-KIN10-ORE1 regulatory axis acts downstream of TDIF-PXY signaling to connect phloem sugar transport with leaf senescence in Arabidopsis.
摘要(中文译文)
TDIF-PXY信号模块最为人所知的功能是参与维管发育，而维管发育与韧皮部功能及长距离糖运输密切相关。然而，TDIF-PXY介导的维管发育如何将韧皮部糖运输和信号传导与叶片衰老联系起来，目前仍 largely 不清楚。本研究表明，TDIF-PXY信号通路缺陷的拟南芥突变体表现出叶片衰老加速、韧皮部运输受损、叶脉胼胝质沉积增加、糖代谢转录重编程以及碳水化合物积累。利用诱导型PXY敲低实验表明，TDIF-PXY信号减弱后所观察到的糖代谢相关基因表达变化主要源于韧皮部运输受损，而非该通路的直接转录输出。遗传学和代谢分析鉴定出海藻糖-6-磷酸（T6P）是导致pxy突变体早衰的关键信号。在机制上，KIN10（SnRK1的催化亚基，受T6P抑制）直接与衰老调控因子ORE1相互作用，并在S115位点将其磷酸化，从而促进其不稳定化。T6P升高抑制KIN10活性，进而减少ORE1在S115位点的磷酸化并稳定ORE1。在叶片自然衰老过程中，TDIF-PXY通路基因的表达和韧皮部运输能力下降，而T6P积累和叶脉胼胝质沉积增加。在韧皮部组织中维持TDIF表达可保持韧皮部运输并延缓衰老。综上所述，这些发现揭示了一条连接维管功能与叶片衰老的T6P-KIN10-ORE1调控轴，提示维管状态可作为叶片衰老启动的内在信号。
Abstract
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, how TDIF-PXY-mediated vascular development connects phloem sugar transport and signaling to leaf senescence remains largely unclear. Here, we show that Arabidopsis mutants defective in TDIF-PXY signaling exhibit accelerated leaf senescence, impaired phloem transport, increased vein callose deposition, transcriptional reprogramming of sugar metabolism, and carbohydrate accumulation. Experiments using inducible PXY knockdown showed that changes in sugar metabolism-related gene expression observed following TDIF-PXY attenuation arise primarily from impaired phloem transport rather than from a direct transcriptional output of this pathway. Genetic and metabolic analyses identified trehalose-6-phosphate (T6P) as a key signal contributing to premature senescence in the pxy mutant. Mechanistically, KIN10, a T6P-inhibited catalytic subunit of SnRK1, interacts directly with the senescence regulator ORE1 and phosphorylates it at S115, thereby promoting its destabilization. Elevated T6P inhibits KIN10 activity, thereby reducing ORE1 phosphorylation at S115 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, suggesting that vascular status serves as an intrinsic cue for the onset of leaf senescence.
如何引用
AMA
Junjie Liu, Yonglun Lv, Zhenpei Pang, Yishan Chu, Wentian Chen, Yang Peng, et al. The T6P-KIN10-ORE1 regulatory axis acts downstream of TDIF-PXY signaling to connect phloem sugar transport with leaf senescence in Arabidopsis.. Plant communications. 2026; doi:10.1016/j.xplc.2026.102029.
APA
Junjie Liu, Yonglun Lv, Zhenpei Pang, Yishan Chu, Wentian Chen, Yang Peng, et al (2026). The T6P-KIN10-ORE1 regulatory axis acts downstream of TDIF-PXY signaling to connect phloem sugar transport with leaf senescence in Arabidopsis.. Plant communications. https://doi.org/10.1016/j.xplc.2026.102029
GB/T 7714
Junjie Liu, Yonglun Lv, Zhenpei Pang, Yishan Chu, Wentian Chen, Yang Peng, et al. The T6P-KIN10-ORE1 regulatory axis acts downstream of TDIF-PXY signaling to connect phloem sugar transport with leaf senescence in Arabidopsis.[J]. Plant communications, 2026 doi:10.1016/j.xplc.2026.102029.
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