The flowering time regulator FLK controls pathogen defense in Arabidopsis thaliana
The flowering time regulator FLK controls pathogen defense in Arabidopsis thaliana
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DOI：
10.1093/plphys/kiad021
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发表时间：
2023-02-09
期刊：
影响因子：
7.4
通讯作者：
Lu，Hua
中科院分区：
文献类型：
--
作者：
Fabian，Matthew;Gao，Min;Lu，Hua
植物抗病性是一个复杂的过程，与发育保持着复杂的平衡。越来越多的证据表明RNA结合蛋白在转录后调控植物防御中的重要性。在拟南芥（Arabidopsis thaliana）加速细胞死亡6-1（acd 6 -1），一个小的组成型防御突变体，其防御水平是在一个反比例的植物大小的抑制基因的遗传筛选中，我们确定了一个典型的开花调控基因FLOWERLOCUS K同源结构域（FLK）的等位基因编码一个假定的蛋白质与三重K同源（KH）重复。KH重复序列是在来自不同生物体的蛋白质中发现的古老RNA结合基序。KH结构域蛋白在病原体抗性中的相关性在很大程度上未被探索。除了开花延迟，flk突变体表现出对细菌病原体假单胞菌的抗性降低和对坏死型真菌病原体灰葡萄孢的抗性增加。我们进一步发现，flk突变损害了基础防御和水杨酸（SA）介导的防御信号。突变分析揭示了FLK和几个主要SA途径基因之间复杂的遗传相互作用。RNA-seq数据显示，FLK调节一些主要的防御和发育相关基因的表达丰度，以及许多基因的选择性剪接。在受FLKisACD 6影响的基因中，其转录物的内含子保留增加受flk突变的影响。因此，本研究为facd 6 - 1的flk抑制机制提供了理论支持，并证实了flk是一个多功能基因，参与了植物的病原防御和发育。
Plant disease resistance is a complex process that is maintained in an intricate balance with development. Increasing evidence indicates the importance of posttranscriptional regulation of plant defense by RNA binding proteins. In a genetic screen for suppressors of Arabidopsis (Arabidopsis thaliana)accelerated cell death 6-1(acd6-1), a small constitutive defense mutant whose defense level is grossly in a reverse proportion to plant size, we identified an allele of the canonical flowering regulatory geneFLOWERING LOCUS K HOMOLOGY DOMAIN(FLK) encoding a putative protein with triple K homology (KH) repeats. The KH repeat is an ancient RNA binding motif found in proteins from diverse organisms. The relevance of KH-domain proteins in pathogen resistance is largely unexplored. In addition to late flowering, theflkmutants exhibited decreased resistance to the bacterial pathogenPseudomonas syringaeand increased resistance to the necrotrophic fungal pathogenBotrytis cinerea. We further found that theflkmutations compromised basal defense and defense signaling mediated by salicylic acid (SA). Mutant analysis revealed complex genetic interactions betweenFLKand several major SA pathway genes. RNA-seq data showed thatFLKregulates expression abundance of some major defense- and development-related genes as well as alternative splicing of a number of genes. Among the genes affected byFLKisACD6, whose transcripts had increased intron retentions influenced by theflkmutations. Thus, this study provides mechanistic support forflksuppression ofacd6-1and establishes thatFLKis a multifunctional gene involved in regulating pathogen defense and development of plants.