Targeted Knockout of Eukaryotic Translation Initiation Factor 4E Confers Bymovirus Resistance in Winter Barley.
Targeted Knockout of Eukaryotic Translation Initiation Factor 4E Confers Bymovirus Resistance in Winter Barley.
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DOI：
10.3389/fgeed.2021.784233
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发表时间：
2021
影响因子：
--
通讯作者：
Kumlehn J
中科院分区：
文献类型：
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作者：
Hoffie RE;Otto I;Perovic D;Budhagatapalli N;Habekuß A;Ordon F;Kumlehn J
真核翻译起始因子4 E（EIF 4 E）是许多植物物种中马铃薯Y病毒属感染的众所周知的易感因子。大麦黄花叶病是由大麦黄花叶病毒（Barley yellow mosaic virus，BaYMV）和大麦轻花叶病毒（Barley mild mosaic virus，BaMMV）引起的一种重要病害，可使冬大麦的产量损失高达50%。在秋季，大麦幼苗的根部被土传疟原虫寄生虫禾谷多粘虫（Polymyxa graminis L.）感染。作为病毒载体在病毒建立和系统传播到植物的上部时，黄色马赛克作为叶子上的第一症状出现。在植物发育的进一步过程中，该疾病导致叶片坏死并增加对霜冻损害的敏感性。由于HvEIF 4 E基因的rym 4和rym 5等位基因变体，目前欧洲超过三分之二的冬大麦品种对BaYMV和BaMMV具有抗性。然而，BaYMV和BaMMV的几个株系已经克服了rym 4和rym 5介导的抗性。因此，大麦育种需要新的抗性赋予等位基因。因此，我们在BaMMV/BaYMV敏感的冬大麦cv.伊格里产生小的插入，导致翻译阅读框的移位，从而导致EIF 4 E的功能丧失。突变发生在原代突变体中的纯合状态。他们的后代证明总是纯合子和完全抗机械接种BaMMV。EIF 4 E基因敲除植物表现出正常的生长习性，并产生籽粒，但表现出产量惩罚。
The Eukaryotic Translation Initiation Factor 4E (EIF4E) is a well-known susceptibility factor for potyvirus infections in many plant species. The barley yellow mosaic virus disease, caused by the bymoviruses Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV), can lead to yield losses of up to 50% in winter barley. In autumn, the roots of young barley plants are infected by the soil-borne plasmodiophoraceous parasite Polymyxa graminis L. that serves as viral vector. Upon viral establishment and systemic spreading into the upper parts of the plants, yellow mosaics occur as first symptoms on leaves. In the further course of plant development, the disease entails leaf necrosis and increased susceptibility to frost damage. Thanks to the rym4 and rym5 allelic variants of the HvEIF4E gene, more than two thirds of current European winter barley cultivars are resistant to BaYMV and BaMMV. However, several strains of BaYMV and BaMMV have already overcome rym4- and rym5-mediated resistance. Accordingly, new resistance-conferring alleles are needed for barley breeding. Therefore, we performed targeted mutagenesis of the EIF4E gene by Cas9 endonuclease in BaMMV/BaYMV-susceptible winter barley cv. “Igri”. Small insertions were generated, resulting in a shift of the translational reading frame, thereby causing the loss-of-function of EIF4E. The mutations occurred in the homozygous state already in the primary mutants. Their progeny proved invariably homozygous and fully resistant to mechanical inoculation with BaMMV. EIF4E knockout plants showed normal growth habit and produced grains, yet exhibited a yield penalty.