Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Department of Plant Pathology, South China Agricultural University, Guangzhou, China.
Guangdong Provincial Key Laboratory of New Technology in Rice Breeding, Guangzhou, China.
Mol Plant Pathol. 2021 Dec;22(12):1587-1598. doi: 10.1111/mpp.13130. Epub 2021 Aug 27.
Rice sheath blight, caused by the soilborne fungus Rhizoctonia solani, causes severe yield losses worldwide. Elucidation of the pathogenic mechanism of R. solani is highly desired. However, the lack of a stable genetic transformation system has made it challenging to examine genes' functions in this fungus. Here, we present functional validation of pathogenicity genes in the rice sheath blight pathogen R. solani by a newly established tobacco rattle virus (TRV)-host-induced gene silencing (HIGS) system using the virulent R. solani AG-1 IA strain GD-118. RNA interference constructs of 33 candidate pathogenicity genes were infiltrated into Nicotiana benthamiana leaves with the TRV-HIGS system. Of these constructs, 29 resulted in a significant reduction in necrosis caused by GD-118 infection. For further validation of one of the positive genes, trehalose-6-phosphate phosphatase (Rstps2), stable rice transformants harbouring the double-stranded RNA (dsRNA) construct for Rstps2 were created. The transformants exhibited reduced gene expression of Rstps2, virulence, and trehalose accumulation in GD-118. We showed that the dsRNA for Rstps2 was taken up by GD-118 mycelia and sclerotial differentiation of GD-118 was inhibited. These findings offer gene identification opportunities for the rice sheath blight pathogen and a theoretical basis for controlling this disease by spray-induced gene silencing.
稻纹枯病由土传病原菌立枯丝核菌引起，在全球范围内造成严重的产量损失。阐明立枯丝核菌的致病机制是非常需要的。然而，由于缺乏稳定的遗传转化系统，使得研究该真菌中基因的功能具有挑战性。在这里，我们使用新建立的烟草脆裂病毒（TRV）-寄主诱导基因沉默（HIGS）系统，以强毒力的立枯丝核菌 AG-1 IA 菌株 GD-118 验证了稻纹枯病病原菌中致病性基因的功能。用 TRV-HIGS 系统将 33 个候选致病性基因的 RNA 干扰构建体注入到黄花烟叶片中。其中 29 个构建体导致由 GD-118 感染引起的坏死显著减少。为了进一步验证其中一个阳性基因，海藻糖-6-磷酸磷酸酶（Rstps2），我们创建了携带 Rstps2 的双链 RNA（dsRNA）构建体的稳定水稻转化体。转化体表现出 Rstps2 的基因表达降低、毒力降低和海藻糖积累减少。我们表明，dsRNA 被 GD-118 菌丝体吸收，并且 GD-118 的菌核分化受到抑制。这些发现为稻纹枯病病原菌的基因鉴定提供了机会，并为通过喷雾诱导基因沉默控制这种疾病提供了理论依据。
