Effect of Autophagy-related Gene PlATG12 on the Growth, Development and Pathogenicity of Peronophythora litchii
CHEN Tai-Xu1,2, YANG Cheng-Dong1,2, YU Ge1,2, LUO Man-Fei1,2, ZHANG Xue1,2, LYU Lin1,2, CHEN Qing-He1,2,*
1 Sanya Nanfan Research Institute/School of Tropical Agriculture and Forestry, Hainan University, Sanya 572025, China; 2 Key Laboratory of Green Prevention and Control of Tropical Agricultural and Forestry Biological Disasters, Ministry of Education, Haikou 570228, China.
Abstract：Autophagy plays an important role in plant resistance to pathogen infection. The autophagy-related protein 12 (ATG12), is mainly involved in the formation and extension of the double-layer membrane of autophagy. However, its role in plant pathogens, especially Oomycetes, has been rarely reported. In order to clarify the role of Peronophythora litchii PlATG12 (GeneBank No. OR909654) in the growth and development, and pathogenesis, the PlATG12 knockout mutants were obtained by CRISPR/Cas9 gene editing and PEG mediated protoplast transformation technology, and the in situ complementation was performed. Phenotypic assay results showed that compared with the wild-type strain SHS3 (WT), the average mycelial growth rate of the ΔPlatg12-77 and ΔPlatg12-315 mutants was decreased by 6.50% and 7.49%, respectively, and the average sporangium number was reduced by 33.86% and 34.02%, respectively. Meanwhile, the zoospore release rate of the mutants was significantly lower than those of WT after incubating at 12 ℃ for 0.5 and 2 h. In addition, the oospore production was only 20.25% and 22.00% of the WT, respectively, and the oospore of type Ⅲ and type Ⅳ increased significantly. The pathogenicity of PlATG12 knockout mutants on litchi (Litchi chinensis) leaves was lower than that of WT. However, the phenotypic defects of PlATG12 knockout mutants were rescued after in situ complementation of PlATG12. These results indicated that autophagy-related gene PlATG12 plays a key role in the growth and development, and pathogenesis of P. litchii. This study provides theoretical basis for the functions of autophagy pathway in the pathogenic process of oomycetes.
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