文献类型： 外文期刊

作者： Yin, Kai ¹ ; Cui, Guobing ¹ ; Bi, Xinping ¹ ; Liang, Meiling ³ ; Hu, Zhijian ¹ ; Deng, Yi Zhen ¹ ;

作者机构： 1.South China Agr Univ, Coll Plant Protect, Key Lab Conservat & Utilizat Subtrop Agrobioresour, Guangzhou 510642, Peoples R China

2.South China Agr Univ, Integrat Microbiol Res Ctr, Guangdong Prov Key Lab Microbial Signals & Dis Con, Guangzhou, Peoples R China

3.Guangdong Acad Agr Sci, Guangdong Prov Key Lab High Technol Plant Protect, Plant Protect, Res Inst, Guangzhou, Peoples R China

关键词： cAMP-PKA signalling pathway; pathogenesis; polyamines; redox; sexual mating/filamentation; Sporisorium scitamineum

期刊名称：MOLECULAR PLANT PATHOLOGY （ 影响因子：4.9； 五年影响因子：5.9 ）

ISSN： 1464-6722

年卷期： 2023 年

页码：

收录情况： SCI

摘要： Sugarcane smut caused by Sporisorium scitamineum seriously impairs sugarcane production and quality. Sexual mating/filamentation is a critical step of S. scitamineum pathogenesis, yet the regulatory mechanisms are not fully understood. In this study, we identified the SsAGA, SsODC, and SsSAMDC genes, which are involved in polyamine biosynthesis in S. scitamineum. Deletion of SsODC led to complete loss of filamentous growth after sexual mating, and deletion of SsAGA or SsSAMDC caused reduced filamentation. Double deletion of SsODC and SsSAMDC resulted in auxotrophy for putrescine (PUT) and spermidine (SPD) when grown on minimal medium (MM), indicating that these two genes encode enzymes that are critical for PUT and SPD biosynthesis. We further showed that low PUT concentrations promoted S. scitamineum filamentation, while high PUT concentrations suppressed filamentation. Disrupted fungal polyamine biosynthesis also resulted in a loss of pathogenicity and reduced fungal biomass within infected plants at the early infection stage. SPD formed a gradient from the diseased part to nonsymptom parts of the cane stem, suggesting that SPD is probably favourable for fungal virulence. Mutants of the cAMP-PKA (SsGPA3-SsUAC1-SsADR1) signalling pathway displayed up-regulation of the SsODC gene and elevated intracellular levels of PUT. SsODC directly interacted with SsGPA3, and sporidia of the ss1uac1 Delta odc Delta mutant displayed abundant pseudohyphae. Furthermore, we found that elevated PUT levels caused accumulation of intracellular reactive oxygen species (ROS), probably by suppressing transcription of ROS-scavenging enzymes, while SPD played the opposite role. Overall, our work proves that polyamines play important roles in the pathogenic development of sugarcane smut fungus, probably by collaboratively regulating intracellular redox homeostasis with the cAMP-PKA signalling pathway.