The sorting nexin Atg20/Snx42 plays an important role in autophagy. The wheat head blight pathogen Fusarium graminearum contains an FgAtg20 protein orthologous to Saccharomyces cerevisiae Atg20/Snx42, but its function remains largely unknown. Here, we report a role for FgAtg20 in regulating morphogenesis and fungal pathogenicity. Cytological observation and Western blot analysis revealed that ΔFgAtg20 mutants are defective in vacuolar transport and proteolysis of GFP‐FgAtg8, indicating that FgAtg20 is required for non‐selective macroautophagy. Furthermore, we found that FgATG20 is necessary for the maturation of FgApe1, an indicator of the cytoplasm‐to‐vacuole targeting (Cvt) pathway. Immunoblot analysis displayed lower level of FgPex14, a peroxisomal integral membrane protein in ΔFgAtg20 mutants, suggesting that pexophagy is impaired. Furthermore, we demonstrate that FgAtg20 forms a complex with FgAtg1, FgAtg11, FgAtg17 and FgAtg24. When considered together, we conclude that FgAtg20 plays a critical role in vegetative growth, conidiation and pathogenicity of the head blight pathogen, and is involved in the Cvt pathway, non‐selective macroautophagy and pexophagy.

中文翻译：

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分选 nexin FgAtg20 参与禾谷镰刀菌的 Cvt 通路、非选择性巨自噬、外自噬和发病机制。

分选连接蛋白 Atg20/Snx42 在自噬中起重要作用。小麦赤霉病病原体禾谷镰刀菌含有与酿酒酵母Atg20/Snx42直系同源的 FgAtg20 蛋白，但其功能在很大程度上仍然未知。在这里，我们报告了 FgAtg20 在调节形态发生和真菌致病性方面的作用。细胞学观察和蛋白质印迹分析表明，ΔFgAtg20突变体在 GFP-FgAtg8 的液泡转运和蛋白水解方面存在缺陷，表明 FgAtg20 是非选择性巨自噬所必需的。此外，我们发现FgATG20FgApe1 是细胞质到液泡靶向 (Cvt) 途径的指示剂，它是 FgApe1 成熟所必需的。免疫印迹分析显示 FgPex14 水平较低，FgPex14 是ΔFgAtg20突变体中的一种过氧化物酶体整合膜蛋白，表明外食道受损。此外，我们证明 FgAtg20 与 FgAtg1、FgAtg11、FgAtg17 和 FgAtg24 形成复合物。综合考虑，我们得出的结论是，FgAtg20 在赤霉病病原体的营养生长、分生孢子形成和致病性中起关键作用，并参与 Cvt 途径、非选择性巨自噬和自噬。