Li Mengsha, Li Teng, Zhou Ming, Li Mengdi, Zhao Yexin, Xu Jingjing, Hu Feng, Li Huixin
College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
College of Science & Technology, Ningbo University, Cixi 315300, China.
Microorganisms. 2021 Apr 30;9(5):970. doi: 10.3390/microorganisms9050970.
Inter-organismal metabolites play important roles in regulating organism behavior and the communication between organisms. Nematodes, the most abundant animals on earth, are crucial participants in soil ecosystems through their interactions with microbes. For example, bacterial-feeding nematodes increase the activity of indole-3-acetic acid (IAA)-producing bacteria and the IAA content in soil. However, the way in which these nematodes interact with bacteria and affect IAA biosynthesis is not well understood. Here, using the model nematode and the plant-beneficial bacterium ZZ21, we examined the effects of nematode excretions or extracts on bacterial IAA biosynthesis. To explore the underlying regulatory mechanism in more detail, we performed transcriptome sequencing and metabolomic analysis. Our findings suggest that extracts promote IAA biosynthesis in ZZ21 by increasing the expression of genes and the abundance of intermediates involved in the indole-3-pyruvic acid (IPyA) pathway. extracts also significantly influenced biosynthetic and metabolic activity in ZZ21. Treatment with extracts promoted pyruvate metabolism, the citrate cycle (TCA) cycle and the production of some TCA-cycle-related amino acids and inhibited oxidative phosphorylation, which induced the accumulation of reduced nicotinamide adenine dinucleotide (NADH). We propose that the extracts altered the metabolism of ZZ21 to help the bacteria resist stress caused by their predator. Our findings indicate that bacterial-feeding nematodes mediate the interaction between nematodes and bacteria via their extracts, providing insights into the ecological function of in soil.
生物间代谢产物在调节生物体行为和生物体间通讯方面发挥着重要作用。线虫是地球上数量最多的动物，通过与微生物的相互作用，它们是土壤生态系统的关键参与者。例如，以细菌为食的线虫会增加土壤中产生吲哚 - 3 - 乙酸（IAA）的细菌的活性以及土壤中的IAA含量。然而，这些线虫与细菌相互作用并影响IAA生物合成的方式尚不清楚。在这里，我们使用模式线虫和植物有益细菌ZZ21，研究了线虫排泄物或提取物对细菌IAA生物合成的影响。为了更详细地探究潜在的调控机制，我们进行了转录组测序和代谢组分析。我们的研究结果表明，提取物通过增加参与吲哚 - 3 - 丙酮酸（IPyA）途径的基因表达和中间体丰度来促进ZZ21中IAA的生物合成。提取物还显著影响了ZZ21中的生物合成和代谢活性。用提取物处理促进了丙酮酸代谢、柠檬酸循环（TCA循环）以及一些与TCA循环相关的氨基酸的产生，并抑制了氧化磷酸化，这导致了还原型烟酰胺腺嘌呤二核苷酸（NADH）的积累。我们提出提取物改变了ZZ21的代谢，以帮助细菌抵抗来自其捕食者的压力。我们的研究结果表明，以细菌为食的线虫通过其提取物介导线虫与细菌之间的相互作用，为土壤中[未提及的线虫名称]的生态功能提供了见解。
