Loss-of-Function Mutations in CsMLO1 Confer Durable Powdery Mildew Resistance in Cucumber (Cucumis sativus L.).
Loss-of-Function Mutations in CsMLO1 Confer Durable Powdery Mildew Resistance in Cucumber (Cucumis sativus L.).
复制标题
CsMLO1 的功能缺失突变赋予黄瓜 (Cucumis sativus L.) 持久的白粉病抗性
DOI：
10.3389/fpls.2015.01155
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发表时间：
2015
影响因子：
5.6
通讯作者：
Cai R
中科院分区：
文献类型：
--
作者：
Nie J;Wang Y;He H;Guo C;Zhu W;Pan J;Li D;Lian H;Pan J;Cai R
黄瓜白粉病是一种严重的世界性真菌病害。黄瓜抗病基因的鉴定对黄瓜抗病育种和生产具有重要意义。在这里，发现在MLO同源基因座CsMLO 1处的自然功能丧失突变赋予黄瓜持久的PM抗性。CsMLO 1编码一种细胞膜蛋白，主要在叶片和子叶中表达，在寄主-病原菌互作早期被PM上调。CsMLO 1的异位表达拯救了拟南芥中PM抗性Atmlo 2 Atmlo 12双突变体对PM敏感的表型。来自世界不同地理区域的驯化和野生抗性黄瓜被发现含有三个独立的自然突变，导致CsMLO 1功能丧失。此外，对抗感PM近等基因系S1003和近等基因系（Pm5.1）进行定量RT-PCR分析，结果表明，乙烯、茉莉酸和水杨酸途径中的几个基因的表达水平没有差异。此外，两个近等基因系用于转录组分析，以探索耐药性的机制。与细胞壁增厚相关的基因可能参与了植物对PM的抗性。这项研究表明，CsMLO 1的功能丧失赋予持久的PM抗性，并且这种功能丧失是必要的，但单独可能不足以使黄瓜具有PM抗性。这些研究结果将有助于黄瓜PM抗性品种的分子育种，以控制这一毁灭性疾病。
Powdery mildew (PM) is a serious fungal disease of cucumber worldwide. The identification of resistance genes is very important for resistance breeding to ensure cucumber production. Here, natural loss-of-function mutations at an MLO homologous locus, CsMLO1, were found to confer durable PM resistance in cucumber. CsMLO1 encoded a cell membrane protein, was mainly expressed in leaves and cotyledons, and was up-regulated by PM at the early stage of host–pathogen interaction. Ectopic expression of CsMLO1 rescued the phenotype of the PM resistant Atmlo2 Atmlo12 double mutant to PM susceptible in Arabidopsis. Domesticated and wild resistant cucumbers originating from various geographical regions of the world were found to harbor three independent natural mutations that resulted in CsMLO1 loss of function. In addition, between the near-isogenic lines (NILs) of PM resistant and susceptible, S1003 and NIL(Pm5.1), quantitative RT-PCR revealed that there is no difference at expression levels of several genes in the pathways of ethylene, jasmonic acid or salicylic acid. Moreover, the two NILs were used for transcriptome profiling to explore the mechanism underlying the resistance. Several genes correlated with plant cell wall thickening are possibly involved in the PM resistance. This study revealed that loss of function of CsMLO1 conferred durable PM resistance, and that this loss of function is necessary but alone may not be sufficient for PM resistance in cucumber. These findings will facilitate the molecular breeding of PM resistant varieties to control this destructive disease in cucumber.