Bacterial blight of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is a devastating rice disease in Southeast Asia and West Africa. OsSWEET14, encoding a sugar transporter, is known to be a major susceptible gene of bacterial blight targeted by four different transcription activator-like (TAL) effectors from either Asian or African Xoo strains. However, the OsSWEET14 single knockout or promoter mutants in the Kitaake background are moderately resistant or even susceptible to African Xoo strains. Therefore, in this study, we knocked out OsSWEET14 in rice cv. Zhonghua 11 background for disease assessment. In this study, CRISPR/Cas9 was utilized to disrupt the function of OsSWEET14 by modifying its corresponding coding region in the genome of rice cv. Zhonghua 11 (CR-S14). In total, we obtained nine different OsSWEET14-mutant alleles. Besides conferring broad-spectrum resistance to Asian Xoo strains, tested mutant alleles also showed strong resistance to African Xoo strain AXO1947. Moreover, the expression of OsSWEET14 was detected in vascular tissues, including the stem, leaf sheath, leaf blade and root. The disruption of OsSWEET14 led to increased plant height without a reduction in yield. Disruption of OsSWEET14 in the Zhonghua 11 background is able to confer strong resistance to African Xoo strain AXO1947 and Asian Xoo strain PXO86. CR-S14 has normal reproductive growth and enhanced plant height under normal growth conditions. These results imply that CR-S14 may serve as a better tester line than sweet14 single-knockout mutant in the Kitaake background for the diagnostic kit for rice blight resistance. The genetic background and increased plant height need to be taken into consideration when utilizing OsSWEET14 for resistant rice breeding.

中文翻译：

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CRISPR / Cas9介导的水稻简历中OsSWEET14突变。中华11赋予对米氏黄单胞菌（Xanthomonas oryzae pv）的抵抗力。水稻没有产量损失。

水稻黄萎病菌引起的细菌性枯萎病。稻米（Xoo）是东南亚和西非的毁灭性水稻病。编码糖转运蛋白的OsSWEET14是细菌性枯萎病的主要易感基因，被来自亚洲或非洲Xoo菌株的四种不同的转录激活因子样（TAL）效应子靶向。然而，在Kitaake背景中的OsSWEET14单敲除或启动子突变体对非洲Xoo菌株具有中等抵抗力甚至敏感。因此，在这项研究中，我们剔除了水稻Cv中的OsSWEET14。中华11疾病评估背景。在这项研究中，CRISPR / Cas9被用于通过修饰水稻cv基因组中相应的编码区来破坏OsSWEET14的功能。中华11（CR-S14）。总共，我们获得了9个不同的OsSWEET14突变等位基因。除了赋予对亚洲Xoo菌株的广谱抗性外，测试的突变等位基因还显示出对非洲Xoo菌株AXO1947的强抗性。此外，在包括茎，叶鞘，叶片和根的血管组织中检测到OsSWEET14的表达。OsSWEET14的破坏导致植物高度增加而产量没有降低。在中华11号背景中破坏OsSWEET14能够赋予非洲Xoo菌株AXO1947和亚洲Xoo菌株PXO86强大的抗性。CR-S14在正常生长条件下具有正常的生殖生长并提高了株高。这些结果表明，在用于抗白叶枯病的诊断试剂盒的Kitaake背景中，CR-S14可以比sweet14单敲除突变体更好地用作测试品系。