Entomopathogenic fungi (EPF) can be experimentally established in several plant species as endophytes. Ecological effects of EPF inoculations on plant growth and plant-herbivore interactions have been demonstrated, potentially by altering plant physiological responses. However, the role of these responses in plant-fungus-herbivore tripartite interactions has not been well elucidated. Steroidal glycoalkaloids (SGAs) are plant specialized metabolites with bioactive properties against arthropod herbivores. Here, the effects of seed treatments by three EPF isolates, representing Beauveria bassiana, Metarhizium brunneum, and M. robertsii, on population growth of two-spotted spider mites (Tetranychus urticae Koch) were evaluated on tomato (Solanum lycopersicum). The levels of two SGAs, α-tomatine and dehydrotomatine, were determined in tomato leaves by LC-MS with and without T. urticae infestations after EPF inoculations. Interestingly, the population growth of T. urticae was significantly highest with M. brunneum and lowest with M. robertsii and B. bassiana at 15 days after infestation. Overall there was a significant negative correlation between SGAs content and the number of T. urticae. The levels of SGAs were significantly induced by T. urticae presence in all treatments, while only M. robertsii showed significantly higher levels of SGAs than M. brunneum and control in one of two experiments. Contrastingly, the effects on SGAs accumulation and population growth of T. urticae did not directly correlate with EPF endophytic colonization patterns of the inoculated plants. This study suggests a link between ecological effects and physiological responses mediated by EPF inoculations and T. urticae infestation with potential implications for plant protection.

昆虫病原真菌 (EPF) 可以通过实验在几种植物物种中建立为内生菌。EPF 接种对植物生长和植物-食草动物相互作用的生态影响已经得到证实，可能是通过改变植物生理反应来实现的。然而，这些反应在植物-真菌-食草动物三方相互作用中的作用尚未得到很好的阐明。甾体糖苷生物碱 (SGA) 是植物特有的代谢物，对节肢动物食草动物具有生物活性。在这里，三种 EPF 分离株（代表白僵菌、绿僵菌和罗伯氏绿僵菌）的种子处理对二斑叶螨（Tetranychus urticae）种群增长的影响Koch) 对番茄 ( Solanum lycopersicum )进行了评估。在 EPF 接种后，在有和没有荨麻疹感染的情况下，通过 LC-MS 在番茄叶片中测定了两种 SGA（α-番茄碱和脱氢番茄碱）的水平。有趣的是，在侵染后 15 天，T. urticae的种群增长在M. brunneum 中显着最高，在M. robertsii和B. bassiana中最低。总体有策略性增长地区的内容和数量之间的显著负相关T.螨。SGAs 的水平在所有处理中都被T. urticae显着诱导，而只有M. robertsii在两个实验之一中，SGA 水平显着高于M. brunneum和对照。相比之下，对T. urticae 的SGA 积累和种群增长的影响与接种植物的 EPF 内生定植模式没有直接关联。这项研究表明生态效应和由 EPF 接种和荨麻疹介导的生理反应之间存在联系，对植物保护具有潜在影响。