Host-induced gene silencing of an essential chitin synthase gene confers durable resistance to Fusarium head blight and seedling blight in wheat
Host-induced gene silencing of an essential chitin synthase gene confers durable resistance to Fusarium head blight and seedling blight in wheat
复制标题
宿主诱导的必需几丁质合酶基因的基因沉默赋予小麦对赤霉病和苗枯病的持久抗性
DOI：
10.1111/pbi.12352
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发表时间：
2015-12-01
影响因子：
13.8
通讯作者：
Liao, Yu-Cai
中科院分区：
文献类型：
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作者：
Cheng, Wei;Song, Xiu-Shi;Liao, Yu-Cai
小麦赤霉病（Fusarium head blight，FHB）和赤霉病（Fusarium seedling blight，FSB）是由镰刀菌属病原体引起的世界性病害。我们报告了来自禾谷镰刀菌（Fg）必需毒力基因甲壳素合成酶（Chs）3b的RNA干扰（RNAi）序列的表达，作为增强小麦植物对真菌病原体抗性的方法。Chs 3b的缺失对Fg是致命的;其他Chs基因家族成员的破坏产生对Fg具有不同影响的敲除突变体。比较表达分析表明，在Chs基因家族成员中，Chs 3b在小麦Fg定殖过程中的表达水平最高。在转基因Fg菌株中，发现对应于Chs 3b的不同区域的三个发夹RNAi构建体使Chs 3b沉默。这三种RNAi构建体在两个独立的优良小麦栽培品种转基因系中的共表达在整个T-3至T-5代中赋予了对FHB和FSB的高水平的稳定、一致的抗性（组合的I型和II型抗性）。共聚焦显微镜显示，在Fg感染的转基因小麦植株的菌丝体受到严重限制。通过北方杂交证实了这三种特异性短干扰RNA在转基因小麦植株中的存在，并且这些RNA有效地下调了定殖在小麦幼苗和穗上的镰刀菌病原体中的Chs 3 b。我们的研究结果表明，宿主诱导的基因沉默的一个重要的真菌几丁质合成酶基因是一种有效的策略，在田间试验条件下提高作物的抗性。
Fusarium head blight (FHB) and Fusarium seedling blight (FSB) of wheat, caused by Fusarium pathogens, are devastating diseases worldwide. We report the expression of RNA interference (RNAi) sequences derived from an essential Fusarium graminearum (Fg) virulence gene, chitin synthase (Chs) 3b, as a method to enhance resistance of wheat plants to fungal pathogens. Deletion of Chs3b was lethal to Fg; disruption of the other Chs gene family members generated knockout mutants with diverse impacts on Fg. Comparative expression analyses revealed that among the Chs gene family members, Chs3b had the highest expression levels during Fg colonization of wheat. Three hairpin RNAi constructs corresponding to the different regions of Chs3b were found to silence Chs3b in transgenic Fg strains. Co-expression of these three RNAi constructs in two independent elite wheat cultivar transgenic lines conferred high levels of stable, consistent resistance (combined type I and II resistance) to both FHB and FSB throughout the T-3 to T-5 generations. Confocal microscopy revealed profoundly restricted mycelia in Fg-infected transgenic wheat plants. Presence of the three specific short interfering RNAs in transgenic wheat plants was confirmed by Northern blotting, and these RNAs efficiently down-regulated Chs3b in the colonizing Fusarium pathogens on wheat seedlings and spikes. Our results demonstrate that host-induced gene silencing of an essential fungal chitin synthase gene is an effective strategy for enhancing resistance in crop plants under field test conditions.