Department of Microbial and Molecular Systems (M2S), CMPG Laboratory for Process Microbial Ecology and Bioinspirational Management (PME&BIM), KU Leuven, Leuven, Belgium.
Leuven Plant Institute (LPI), KU Leuven, Leuven, Belgium.
PLoS One. 2022 Sep 6;17(9):e0273791. doi: 10.1371/journal.pone.0273791. eCollection 2022.
Entomopathogenic fungi can adopt an endophytic lifestyle and provide protection against insect herbivores and plant pathogens. So far, most studies have focused on Beauveria bassiana to increase plant resistance against abiotic and biotic stresses, while only little is known for other entomopathogenic fungi. In this study, we investigated whether root inoculation of sweet pepper (Capsicum annuum L.) by the entomopathogenic fungi Akanthomyces muscarius ARSEF 5128 and B. bassiana ARSEF 3097 can improve resistance against the tobacco peach aphid Myzus persicae var. nicotianae. First, dual-choice experiments were performed to test the hypothesis that the fungi deter aphids via modifying plant volatile profiles. Next, we tested the hypothesis that endophytic colonization negatively affects aphid life history traits, such as fecundity, development and mortality rate. Aphids were significantly attracted to the odor of plants inoculated with A. muscarius over non-inoculated plants. Plants inoculated with A. muscarius emitted significantly higher amounts of β-pinene than non-inoculated plants, and significantly higher amounts of indole than B. bassiana-inoculated and non-inoculated plants. Inoculation with the fungal strains also caused significantly higher emission of terpinolene. Further, both aphid longevity and fecundity were significantly reduced by 18% and 10%, respectively, when feeding on plants inoculated with A. muscarius, although intrinsic rate of population increase did not differ between inoculated and non-inoculated plants. Sweet pepper plants inoculated with B. bassiana ARSEF 3097 did not elicit a significant behavioral response nor affected the investigated life history traits. We conclude that endophytic colonization by entomopathogenic fungi has the potential to alter olfactory behavior and performance of M. persicae var. nicotianae, but effects are small and depend on the fungal strain used.
昆虫病原真菌可以采用内生生活方式，并为昆虫食草动物和植物病原体提供保护。到目前为止，大多数研究都集中在球孢白僵菌上，以提高植物对非生物和生物胁迫的抗性，而对于其他昆虫病原真菌知之甚少。在这项研究中，我们研究了内生真菌蜡蚧轮枝菌 ARSEF 5128 和球孢白僵菌 ARSEF 3097 对甜椒（Capsicum annuum L.）根系接种是否可以提高对烟蚜 Myzus persicae var. nicotianae 的抗性。首先，进行了双选择实验，以测试真菌通过改变植物挥发性图谱来阻止蚜虫的假设。接下来，我们测试了内生定殖是否会对蚜虫的生活史特征（如繁殖力、发育和死亡率）产生负面影响的假设。蚜虫明显被接种 A. muscarius 的植物气味所吸引，而不是未接种的植物。与未接种的植物相比，接种 A. muscarius 的植物β-蒎烯的释放量显著增加，与 B. bassiana 接种和未接种的植物相比，吲哚的释放量也显著增加。接种真菌菌株还导致萜品烯的释放量显著增加。此外，当蚜虫在接种 A. muscarius 的植物上取食时，其寿命和繁殖力分别显著降低了 18%和 10%，尽管接种和未接种的植物的种群内增长率没有差异。接种 B. bassiana ARSEF 3097 的甜椒植物没有引起明显的行为反应，也没有影响所研究的生活史特征。我们得出的结论是，内生真菌的定殖有可能改变烟蚜 Myzus persicae var. nicotianae 的嗅觉行为和表现，但效果很小，取决于所用的真菌菌株。
