Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China.
J Appl Microbiol. 2020 Aug;129(2):411-421. doi: 10.1111/jam.14619. Epub 2020 Mar 9.
Mitochondrial fission is an essential dynamics that maintains mitochondrial morphology and function. This study seeks to determine the roles of mitochondrial fission in the filamentous entomopathogenic fungus Beauveria bassiana.
Three fission-related genes (BbFis1, BbMdv1 and BbDnm1) were functionally characterized via protein intracellular localization and construction of gene disruption mutants.
Mitochondrial localization was only observed for BbFis1 which interacts with BbMdv1, but BbMdv1 did not have interaction with BbDnm1. Single disruption mutant of three genes generated the elongated and enlarged mitochondria which could not be eliminated via the mitophagy. Three mutant strains displayed the reduced ATP synthesis and vegetative growth compared with the wild type. Three genes were involved in the early stage of conidiation and unnecessary for the late stage. However, all three genes significantly contribute to blastospore development under submerged condition, and the loss of BbMdv1 had the greatest effects compared with the losses of BbFis1 or BbDnm1. Finally, disruption of three genes significantly attenuated fungal virulence, but their mutations had different influences.
In addition to their consistent roles in mitochondrial division and mitophagy, three fission-related genes perform divergent roles in the development and virulence of the entomopathogenic fungus B. bassiana.
This study shows that mitochondrial fission is associated with lifecycle of B. bassiana. These findings provide information for the manipulation of fungal physiology and facilitate the application of entomopathogenic fungi.
线粒体裂变是维持线粒体形态和功能的基本动态过程。本研究旨在确定线粒体裂变在丝状昆虫病原真菌球孢白僵菌中的作用。
通过蛋白质细胞内定位和基因敲除突变体的构建，对三个与裂变相关的基因（BbFis1、BbMdv1 和 BbDnm1）进行了功能表征。
只有 BbFis1 观察到线粒体定位，它与 BbMdv1 相互作用，但 BbMdv1 与 BbDnm1 没有相互作用。三个基因的单一敲除突变导致线粒体伸长和增大，无法通过线粒体自噬消除。与野生型相比，三个突变株的 ATP 合成和营养生长能力降低。三个基因参与了早期分生孢子的形成，但对后期阶段不是必需的。然而，在浸没条件下，所有三个基因都显著促进了芽生孢子的发育，并且与 BbFis1 或 BbDnm1 的缺失相比，BbMdv1 的缺失影响最大。最后，三个基因的敲除显著削弱了真菌的毒力，但它们的突变有不同的影响。
除了在线粒体分裂和线粒体自噬中发挥一致作用外，三个与裂变相关的基因在昆虫病原真菌白僵菌的发育和毒力中发挥着不同的作用。
这项研究表明，线粒体裂变与白僵菌的生命周期有关。这些发现为真菌生理学的操纵提供了信息，并促进了昆虫病原真菌的应用。
