Capsicum annuum HsfB2a Positively Regulates the Response to Ralstonia solanacearum Infection or High Temperature and High Humidity Forming Transcriptional Cascade with CaWRKY6 and CaWRKY40
Capsicum annuum HsfB2a Positively Regulates the Response to Ralstonia solanacearum Infection or High Temperature and High Humidity Forming Transcriptional Cascade with CaWRKY6 and CaWRKY40
复制标题
辣椒 HsfB2a 正向调节对青枯菌感染或高温高湿的反应，与 CaWRKY6 和 CaWRKY40 形成转录级联
DOI：
10.1093/pcp/pcy181
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发表时间：
2018-12-01
影响因子：
4.9
通讯作者：
He, Shuilin
中科院分区：
文献类型：
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作者：
Ashraf, Muhammad Furqan;Yang, Sheng;He, Shuilin
辣椒（Capsicum annuum）植物接种病原细菌青枯雷尔氏菌和高温高湿（HTHH）条件的反应先前被发现是由转录因子CaWRKY 6和CaWRKY 40协调的;然而，潜在的分子机制尚不清楚。在此，我们确定和功能特点CaHsfB 2a，一个核定位的热休克因子参与辣椒免疫力的R。青枯菌接种（RSI）和对HTHH的耐受性。CaHsfB 2a在辣椒植物中由RSI或HTHH以及由水杨酸（SA）、茉莉酸甲酯（MeJA）、乙烯（ETH）或脱落酸（阿坝）的外源施用诱导转录。病毒诱导的基因沉默（VIGS）的CaHsfB 2a显着削弱辣椒免疫RSI，阻碍HTHH的耐受性，并减少表达的免疫和耐热性相关的标记基因，如CaHIR 1，CaNPR 1，CaABR 1和CaHSP 24。同样，瞬时过表达的CaHsfB 2a在辣椒叶片诱导过敏反应（HR）样细胞死亡和H2 O2的积累和上调上述标记基因以及CaWRKY 6和CaWRKY 40。染色质免疫沉淀（ChIP）和微量热泳（MST）分析表明，CaHsfB 2a绑定的CaWRKY 6和CaWRKY 40的启动子。在平行实验中，我们通过ChIP-PCR和MST确定CaHsfB 2a直接受CaWRKY 40调节，但间接受CaWRKY 6调节。累积起来，我们的研究结果表明，CaHsfB 2a积极调节植物对RSI的免疫力和耐受HTHH，通过转录级联反应和正反馈回路涉及CaWRKY 6和CaWRKY 40。
The responses of pepper (Capsicum annuum) plants to inoculation with the pathogenic bacterium Ralstonia solanacearum and to high-temperature-high-humidity (HTHH) conditions were previously found to be coordinated by the transcription factors CaWRKY6 and CaWRKY40; however, the underlying molecular mechanism was unclear. Herein, we identified and functionally characterized CaHsfB2a, a nuclear-localized heat shock factor involved in pepper immunity to R. solanacearum inoculation (RSI) and tolerance to HTHH. CaHsfB2a is transcriptionally induced in pepper plants by RSI or HTHH and by exogenous application of salicylic acid (SA), methyl jasmonate (MeJA), ethylene (ETH), or abscisic acid (ABA). Virus-induced gene silencing (VIGS) of CaHsfB2a significantly impaired pepper immunity to RSI, hampered HTHH tolerance, and curtailed expression of immunity- and thermotolerance-associated marker genes such as CaHIR1, CaNPR1, CaABR1, and CaHSP24. Likewise, transient overexpression of CaHsfB2a in pepper leaves induced hypersensitive response (HR)-like cell death and H2O2 accumulation and upregulated the above-mentioned marker genes as well as CaWRKY6 and CaWRKY40. Chromatin immunoprecipitation (ChIP) and microscale thermophoresis (MST) analysis revealed that CaHsfB2a bound the promoters of both CaWRKY6 and CaWRKY40. In a parallel experiment, we determined by ChIP-PCR and MST that CaHsfB2a was regulated directly by CaWRKY40 but indirectly by CaWRKY6. Cumulatively, our results suggest that CaHsfB2a positively regulates plant immunity against RSI and tolerance to HTHH, via transcriptional cascades and positive feedback loops involving CaWRKY6 and CaWRKY40.