The Amino Acid Permease MoGap1 Regulates TOR Activity and Autophagy in Magnaporthe oryzae

Abstract

Rice is an important food crop all over the world. It can be infected by the rice blast fungus Magnaporthe oryzae, which results in a significant reduction in rice yield. The infection mechanism of M. oryzae has been an academic focus for a long time. It has been found that G protein, AMPK, cAMP-PKA, and MPS1-MAPK pathways play different roles in the infection process. Recently, the function of TOR signaling in regulating cell growth and autophagy by receiving nutritional signals generated by plant pathogenic fungi has been demonstrated, but its regulatory mechanism in response to the nutritional signals remains unclear. In this study, a yeast amino acid permease homologue MoGap1 was identified and a knockout mutant of MoGap1 was successfully obtained. Through a phenotypic analysis, a stress analysis, autophagy flux detection, and a TOR activity analysis, we found that the deletion of MoGap1 led to a sporulation reduction as well as increased sensitivity to cell wall stress and carbon source stress in M. oryzae. The ΔMogap1 mutant showed high sensitivity to the TOR inhibitor rapamycin. A Western blot analysis further confirmed that the TOR activity significantly decreased, which improved the level of autophagy. The results suggested that MoGap1, as an upstream regulator of TOR signaling, regulated autophagy and responded to adversities such as cell wall stress by regulating the TOR activity.

MoLst8 regulates autophagy and lipid homeostasis inMagnaporthe oryzae

“…TOR's activity is modulated by various proteins like MoVast1/2, MoGap1, ASD4, TIP41, and IMP1, influencing different aspects of fungal physiology and pathogenicity. Mutations in these proteins alter TOR signaling, leading to phenotypic changes [19,24,31,[48][49][50]. Our study revealed the genome of rice blast fungus contains TOR complex proteins, with MoLst8 as a significant component.…”

A New Insight into 6-Pentyl-2H-pyran-2-one against Peronophythora litchii via TOR Pathway

“…According to previous research reports, the TOR pathway plays a crucial role in regulating the vegetative growth and virulence of phytopathogenic fungi [25,36]. TOR and autophagy play a key role in cell growth and virulence-related processes in pathogens, and TOR is one of the negative regulatory factors of autophagy [37]. Comparative transcriptomic analyses revealed significant difference in the expression pattern of four TOR pathway-related genes compared to autophagy-related genes in P. litchii strains challenged with 6PP.…”