Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance
Differential activities of maize plant elicitor peptides as mediators of immune signaling and herbivore resistance
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DOI：
10.1111/tpj.15022
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发表时间：
2020-12-02
期刊：
影响因子：
7.2
通讯作者：
Huffaker，Alisa
中科院分区：
文献类型：
--
作者：
Poretsky，Elly;Dressano，Keini;Huffaker，Alisa
植物激发子多肽(Pep)是保守的防御反应调节因子，也是研究损伤相关分子模式诱导免疫的模型。虽然在大多数物种中以多基因家族的形式存在，但这些多基因家族的功能相关性在很大程度上仍未确定。虽然拟南芥Pep似乎在功能上存在很大的冗余，但以前研究Pep诱导的玉米反应(Zm)的工作暗示了功能的特异性。为了更好地确定单个ZmPep及其同源受体(ZmPEPR)的功能，通过评估防御相关植物激素、特殊代谢产物和全球基因表达模式的变化，结合异源表达分析和CRISPR/Cas9基因敲除植物的分析，对ZmPEPR的活性进行了检测。除了简单地描述单独的ZmPep和ZmPEPR活动外，这些实验还导致了对PEP信号机制的一些新的见解。ZmPROPEP和其他油质前体被发现含有多个活性PEP，这是以前在这个家族中没有观察到的现象。总共鉴定了七个新的ZmPep，发现这些肽具有特定的活性，由其响应输出的相对大小定义，而不是由唯一性定义。ZmPep诱导的茉莉酸和乙烯水平的变化与诱导的防御反应的大小之间存在显著的相关性，表明ZmPep可能通过调节植物激素水平的变阻器来集体调节免疫输出。多肽结构-功能研究和配体-受体模型揭示了ZmPep功能的关键结构特征，并导致ZmPep5a被确定为一种潜在的拮抗肽，能够竞争性地抑制其他ZmPep的活性，这是该家族以前没有观察到的调节机制。
Plant elicitor peptides (Peps) are conserved regulators of defense responses and models for the study of damage‐associated molecular pattern‐induced immunity. Although present as multigene families in most species, the functional relevance of these multigene families remains largely undefined. While Arabidopsis Peps appear largely redundant in function, previous work examining Pep‐induced responses in maize (Zm) implied specificity of function. To better define the function of individual ZmPeps and their cognate receptors (ZmPEPRs), activities were examined by assessing changes in defense‐associated phytohormones, specialized metabolites and global gene expression patterns, in combination with heterologous expression assays and analyses of CRISPR/Cas9‐generated knockout plants. Beyond simply delineating individual ZmPep and ZmPEPR activities, these experiments led to a number of new insights into Pep signaling mechanisms. ZmPROPEP and other poaceous precursors were found to contain multiple active Peps, a phenomenon not previously observed for this family. In all, seven new ZmPeps were identified and the peptides were found to have specific activities defined by the relative magnitude of their response output rather than by uniqueness. A striking correlation was observed between individual ZmPep‐elicited changes in levels of jasmonic acid and ethylene and the magnitude of induced defense responses, indicating that ZmPeps may collectively regulate immune output through rheostat‐like tuning of phytohormone levels. Peptide structure–function studies and ligand–receptor modeling revealed structural features critical to the function of ZmPeps and led to the identification of ZmPep5a as a potential antagonist peptide able to competitively inhibit the activity of other ZmPeps, a regulatory mechanism not previously observed for this family.