Abscisic acid facilitates phosphate acquisition through the transcription factor ABA INSENSITIVE5 in Arabidopsis

第一作者：Yu Zhang

第一单位：河南大学

通讯作者：Wen-Cheng Liu

 Abstarct 

背景回顾：Low phosphate (LP) in soil is a common nutrient stress that severely restricts agricultural production, but the role, if any, of the major stress phytohormone abscisic acid (ABA) in plant phosphate (Pi) starvation responses remains elusive. 

土壤低磷是一个比较常见的营养胁迫，严重限制了农作物的产量；但是，植物激素脱落酸（ABA）是否在植物磷饥饿响应中发挥作用还不清楚。

主要发现：Here, we report that LP-induced ABA accumulation promotes Pi uptake in an ABA INSENSITIVE5 (ABI5)-dependent manner in Arabidopsis thaliana. 

本文中，作者发现低磷诱导的ABA积累会促进拟南芥对Pi的吸收，并且该过程依赖于ABI5。

结果1-低磷诱导ABA合成：LP significantly activated plant ABA biosynthesis, metabolism, and stress responses, suggesting a role of ABA in plant response to Pi availability. 

低磷能够显著激活植株体内的ABA生物合成、代谢和胁迫响应，说明ABA在植物响应磷可用性中发挥某种作用。

结果2-低磷响应依赖于内源ABA合成：LP-induced ABA accumulation and expression of two major high-affinity phosphate transporter genes PHOSPHATE TRANSPORTER1;1/1;4 (PHT1;1/1;4) were severely impaired in a mutant lacking BETA-GLUCOSIDASE1 (BG1), which converts conjugated ABA to active ABA, and the mutant had shorter root and less Pi content than the wild-type plant under LP. 

BG1作用于水解结合葡萄糖的ABA，释放出具生物活性的ABA，而BG1的功能缺失会导致低磷不再能诱导植株ABA积累以及两个高亲和力磷酸转运蛋白基因PHT1;1/1;4的表达，并且相比于野生型，bg1突变体在低磷条件下的根长更短、含Pi量更低。

结果3-ABI5参与低磷响应：Moreover, a mutant of ABI5, the central transcription factor in ABA signaling, also exhibited suppressed root elongation and had reduced Pi content under LP. ABI5 facilitated phosphate acquisition by activating the expression of PHT1;1 by directly binding to its promoter, while overexpressing PHT1;1 completely rescued its reduced Pi content under LP. 

此外，ABA信号转导核心转录因子ABI5的功能缺失突变也会导致植株在低磷条件下根伸长受抑制、含Pi量降低的表型。ABI5会通过直接结合到PHT1;1基因的启动子上，激活后者的表达，从而促进植株对Pi的获取。过表达PHT1;1能够完全互补abi5突变体在低磷条件下的含Pi量降低表型。

结论：Together, our findings illustrate a molecular mechanism by which ABA positively modulates phosphate acquisition through ABI5 in Arabidopsis response to phosphate deficiency.

综上，本文的研究揭示了ABA能够通过ABI5正调控植株在低磷条件下对于磷的获取。

 刘文成 

doi: https://doi.org/10.1111/tpj.15791

Journal: the plant journal

​First Published: May 04, 2022