Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China.
mBio. 2023 Apr 25;14(2):e0304922. doi: 10.1128/mbio.03049-22. Epub 2023 Feb 21.
Many filamentous fungi develop a conidiation process as an essential mechanism for their dispersal and survival in natural ecosystems. However, the mechanisms underlying conidial persistence in environments are still not fully understood. Here, we report that autophagy is crucial for conidial lifespans (i.e., viability) and vitality (e.g., stress responses and virulence) in the filamentous mycopathogen Beauveria bassiana. Specifically, Atg11-mediated selective autophagy played an important, but not dominant, role in the total autophagic flux. Furthermore, the aspartyl aminopeptidase Ape4 was found to be involved in conidial vitality during dormancy. Notably, the vacuolar translocation of Ape4 was dependent on its physical interaction with autophagy-related protein 8 (Atg8) and associated with the autophagic role of Atg8, as determined through a truncation assay of a critical carboxyl-tripeptide. These observations revealed that autophagy acted as a subcellular mechanism for conidial recovery during dormancy in environments. In addition, a novel Atg8-dependent targeting route for vacuolar hydrolase was identified, which is essential for conidial exit from a long-term dormancy. These new insights improved our understanding of the roles of autophagy in the physiological ecology of filamentous fungi as well as the molecular mechanisms involved in selective autophagy. Conidial environmental persistence is essential for fungal dispersal in ecosystems while also serving as a determinant for the biocontrol efficacy of entomopathogenic fungi during integrated pest management. This study identified autophagy as a mechanism to safeguard conidial lifespans and vitality postmaturation. In this mechanism, the aspartyl aminopeptidase Ape4 translocates into vacuoles via its physical interaction with autophagy-related protein 8 (Atg8) and is involved in conidial vitality during survival. The study revealed that autophagy acted as a subcellular mechanism for maintaining conidial persistence during dormancy, while also documenting an Atg8-dependent targeting route for vacuolar hydrolase during conidial recovery from dormancy. Thus, these observations provided new insight into the roles of autophagy in the physiological ecology of filamentous fungi and documented novel molecular mechanisms involved in selective autophagy.
许多丝状真菌通过形成分生孢子来进行繁殖，这是它们在自然生态系统中进行扩散和生存的重要机制。然而，分生孢子在环境中的持久性的相关机制仍然没有完全被理解。在这里，我们报告说自噬对于丝状真菌虫生真菌白僵菌的分生孢子的寿命（即活力）和活力（例如应激反应和毒力）至关重要。具体来说，Atg11 介导的选择性自噬在总自噬通量中发挥了重要作用，但不是主要作用。此外，发现天冬氨酰氨基肽酶 Ape4 参与了休眠期间的分生孢子活力。值得注意的是，Ape4 的液泡易位依赖于它与自噬相关蛋白 8（Atg8）的物理相互作用，并与 Atg8 的自噬作用相关，这通过关键的羧基三肽截断实验来确定。这些观察结果表明，自噬作为一种亚细胞机制，用于在环境中休眠期间恢复分生孢子。此外，鉴定了一种新的液泡水解酶依赖 Atg8 的靶向途径，这对于分生孢子从长期休眠中逸出至关重要。这些新的见解提高了我们对自噬在丝状真菌生理生态中的作用以及参与选择性自噬的分子机制的理解。分生孢子对环境的持久性对于真菌在生态系统中的扩散至关重要，同时也是在综合虫害管理中进行生防时，虫生真菌生物防治效果的决定因素。本研究鉴定了自噬作为一种保障分生孢子成熟后寿命和活力的机制。在这种机制中，天冬氨酰氨基肽酶 Ape4 通过与自噬相关蛋白 8（Atg8）的物理相互作用易位到液泡中，并参与了生存过程中的分生孢子活力。研究表明，自噬作为一种亚细胞机制，在休眠期间维持分生孢子的持久性，同时也记录了自噬相关蛋白 8（Atg8）在分生孢子从休眠中恢复过程中用于液泡水解酶的靶向途径。因此，这些观察结果为自噬在丝状真菌生理生态中的作用提供了新的见解，并记录了参与选择性自噬的新的分子机制。
