Background

Xanthomonas oryzae (Xo) is one of the important pathogenic bacterial groups affecting rice production. Its pathovars Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) cause bacterial blight and bacterial leaf streak in rice, respectively. Xo infects host plants by relying mainly on its transcription activator-like effectors (TALEs) that bind to host DNA targets, named effector binding elements (EBEs), and induce the expression of downstream major susceptibility genes. Blocking TALE binding to EBE could increase rice resistance to the corresponding Xo.

Findings

We used CRISPR/Cas9 to edit the EBEs of three major susceptibility genes (OsSWEET11, OsSWEET14 and OsSULTR3;6) in the rice varieties Guihong 1 and Zhonghua 11. Both varieties have a natural one-base mutation in the EBE of another major susceptibility gene (OsSWEET13) which is not induced by the corresponding TALE. Two rice lines GT0105 (from Guihong 1) and ZT0918 (from Zhonghua 11) with target mutations and transgene-free were obtained and showed significantly enhanced resistance to the tested strains of Xoo and Xoc. Furthermore, under simulated field conditions, the morphology and other agronomic traits of GT0105 and ZT0918 were basically the same as those of the wild types.

Conclusions

In this study, we first reported that the engineering rice lines obtained by editing the promoters of susceptibility genes are resistant to Xoo and Xoc, and their original agronomic traits are not affected.

中文翻译：

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水稻对白叶枯病和细菌叶片条纹的工程抗性

背景

水稻黄单胞菌（Xohomonas oryzae，Xo）是影响水稻生产的重要致病细菌群之一。它的可怜的Xanthomonas oryzae pv。米（Xoo）和黄单胞菌（Xanthomonas oryzae）。空心稗（XOC）原因分别白叶枯病和水稻细菌性条斑。Xo主要依靠其转录激活因子样效应物（TALE）感染宿主植物，该效应物与宿主DNA靶标结合，称为效应子结合元件（EBE），并诱导下游主要易感基因的表达。阻断TALE与EBE的结合可以增加水稻对相应Xo的抗性。

发现

我们使用CRISPR / Cas9编辑了水稻品种贵红1号和中华11号中三个主要易感基因（OsSWEET11，OsSWEET14和OsSULTR3; 6）的EBE。两个品种在另一个主要易感基因的EBE中均具有天然的一碱基突变。 （OsSWEET13），这不是由相应的TALE引起的。获得了两个具有靶点突变且无转基因的水稻品系GT0105（来自桂红1号）和ZT0918（来自中华11号），并显示出对Xoo和Xoc菌株的抗性显着增强。此外，在模拟田间条件下，GT0105和ZT0918的形态和其他农艺性状与野生型基本相同。

结论

在这项研究中，我们首先报道了通过编辑易感基因的启动子获得的工程水稻品系对Xoo和Xoc具有抗性，并且它们的原始农艺性状不受影响。