Coordination of plant growth and abiotic stress responses by Tryptophan Synthase β Subunit1 through modulating tryptophan and ABA homeostasis in Arabidopsis

第一作者：Wen-Cheng Liu

第一单位：武汉大学

通讯作者：Ying-Tang Lu

 Abstarct 

背景回顾：To adjust to changing environments, plants have evolved elaborate regulatory mechanisms balancing their growth with their stress responses. It is currently unknown whether and how the growth-related hormone auxin and stress hormone abscisic acid (ABA) are coordinated in this trade-off. 

植物为了适应不断变化的环境，演化出复杂的调控机制以平衡生长与胁迫响应。目前，对于植物生长相关激素生长素和胁迫相关激素脱落酸（ABA）之间是否以及如何协调以平衡生长与胁迫响应尚不清楚。

主要研究：Here, we show that TRYPTOPHAN (Trp) SYNTHASE β SUBUNIT1 (TSB1) is involved in the coordination of Trp and ABA, thereby affecting plant growth and abiotic stress responses. 

本文中，作者发现色氨酸合酶β亚基TSB1参与了色氨酸与ABA之间的协调，从而影响植物的生长和胁迫响应。

结果1-TSB1表达模式及生物学功能：Plants experiencing high salinity or drought display reduced TSB1 expression, resulting in decreased tryptophan and auxin accumulation, and thus reduced growth.

植物在经历高盐胁迫或者干旱胁迫后会降低TSB1基因的表达，导致植株体内色氨酸和生长素的含量减少，从而减缓生长。

结果2-TSB1突变体表型：In comparison with the wild type, the amiR-TSB1 lines and TSB1 mutants exhibited repressed growth under non-stress conditions but have enhanced ABA accumulation and stress tolerance when subjected to salt or drought stress. 

与野生型相比，amiR-TSB1株系和TSB1功能缺失突变株系在非胁迫条件下生长受到明显抑制，但是在盐胁迫或者干旱胁迫条件下ABA含量增多，相关胁迫的抗性也得到了增强。

结果3-TSB1互作蛋白BG1：Furthermore, TSB1 interacts with and inhibits β-GLUCOSIDASE1 (BG1), which hydrolyses glucose-conjugated ABA into active ABA. The mutation of BG1 in the amiR-TSB1 lines compromised their increased ABA accumulation and enhanced stress tolerance. 

此外，TSB1能够与β-葡萄糖苷酶BG1互作，后者能够水解结合葡萄糖的ABA，释放出具生物活性的ABA。在amiR-TSB1株系中再突变BG1基因能够破坏原本ABA积累的增加和胁迫抗性的增强。

结果4-过氧化氢影响TSB1-BG1互作：Moreover, stress-induced H₂O2 interrupted the interaction between TSB1 and BG1 by sulfenylating cysteine-308 of TSB1, relieving the TSB1-mediated inhibition of BG1 activity. 

此外，胁迫诱导的过氧化氢通过磺酰化TSB1蛋白308号位的半胱氨酸，打断TSB1和BG1之间的互作，从而减缓了由TSB1介导的BG1活性抑制。

结论：Taken together, we revealed that TSB1 is a key coordinator of plant growth and stress responses through balancing Trp and ABA homeostasis.

综上，本文的研究揭示了TSB1通过平衡植物体内色氨酸与ABA的内稳态，介导植物生长和胁迫响应之间的平衡。

 吕应堂 

doi: https://doi.org/10.1016/j.molp.2022.04.009

Journal: Molecular Plant

Published date: April 28, 2022