Abstract：
Metarhizium spp. have emerged as an alternative to chemical pesticides for protecting crops from insect pest. Here, we investigated midgut microbial community and metabolites of Spodoptera litura at three different timepoints after infection with Metarhizium flavoviride. The innate immune system of S. litura was activated with levels of polyphenol oxidase, carboxylesterase, multifunctional oxidase, and glutathione S-transferase activity significantly increasing. Exposure to the fungal pathogen also altered bacterial abundance and diversity in host\'s midgut, and these changes varied depending on the time elapsed since exposure. We identified more operational taxonomic units in the treated samples as compared to the control samples at all tested time points. A total of 372 metabolites were identified, and 88, 149, and 142 differentially accumulated metabolites (DAMs) were identified between the treatment and control groups at 3 timepoints after treatment, respectively. Based on the changes of DAMs in response to M. flavoviride infection at different timepoints and significantly enriched KEGG pathways, we speculated that \"tyrosine metabolism,\" \"galactose metabolism,\" \"ATP-binding cassette transporters,\" \"neuroactive ligand-receptor interaction,\" \"purine metabolism,\" \"arginine and proline metabolism,\" \"beta-alanine metabolism,\" \"lysosome,\" and \"carbon metabolism\" may participate in the metabolic-level defense response. An integrated pathway-level analysis of the 16S-rDNA and metabolomic data illustrated the connections and interdependencies between the metabolic responses of S. litura and the midgut microorganisms to M. flavoviride infection. This work emphasizes the value of integrated analyses of insect-pathogen interactions, provides a framework for future studies of critical microorganisms and metabolic determinants of these interactions, establishes a theoretical basis for the sustainable use of M. flavoviride.
摘要：
绿僵菌属。已经成为化学农药的替代品，用于保护作物免受虫害。这里,我们调查了斜纹夜蛾感染黄花绿僵菌后三个不同时间点的中肠微生物群落和代谢产物。Litura的先天免疫系统被多酚氧化酶水平激活，羧酸酯酶，多功能氧化酶，谷胱甘肽S-转移酶活性显著增加。暴露于真菌病原体也改变了宿主中肠的细菌丰度和多样性，这些变化取决于曝光后经过的时间。在所有测试的时间点,与对照样品相比,我们在处理的样品中鉴定了更多的操作分类单位。总共鉴定出372种代谢物，在治疗后的3个时间点，在治疗组和对照组之间鉴定出88、149和142种差异积累的代谢物（DAMs），分别。基于不同时间点DAMs对Flavoviride感染的反应变化，并显着丰富了KEGG途径，我们推测，“酪氨酸代谢，“\”半乳糖代谢，\“\”ATP结合盒转运蛋白，神经活性配体-受体相互作用，嘌呤代谢，精氨酸和脯氨酸代谢，β-丙氨酸代谢，\"\"溶酶体,“碳代谢”和“碳代谢”可能参与代谢水平的防御反应。对16S-rDNA和代谢组学数据的综合途径水平分析说明了斜纹链球菌和中肠微生物对黄花支原体感染的代谢反应之间的联系和相互依赖性。这项工作强调了昆虫-病原体相互作用综合分析的价值，为这些相互作用的关键微生物和代谢决定因素的未来研究提供了框架，为黄维脲的可持续利用奠定了理论基础。
