第1458回生物科学セミナー

Effects of microbial volatiles on fungi and plants

Hao-Jen Huang(Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan)

2023年03月28日(火)    15:00-16:30  理学部2号館223号室   

Plant-microbe interaction plays diverse roles in the modulation of plant growth, stress tolerance and disease resistance. Chemical communication is one of the strategies that coordinate plant-microbe-microbe interactions. Microbial volatile compounds (mVCs) are volatile metabolites emitted by microorganisms and serve as the gaseous signals in chemical communication between plants and microorganisms. Bacteria and fungi are often found living together in ecosystems. However, the molecular mechanisms involved in bacterial-fungal interactions (BFIs) are largely unknown. Here, we found that Paenarthrobacter ureafaciens volatile compounds (VCs) inhibited the growth of several fungal pathogens and model yeast Saccharomyces cerevisiae. To further examine the antifungal mechanisms, we took advantages in fungal model organism S. cerevisiae. Antifungal volatiles treatment resulted in 1030 differentially expressed genes (DEGs). Based on GO and KEGG enrichment analysis, the identified genes were involved in mitochondial dysfunction, cell wall and membrane integrity, mitophagy, cellular metabolims, iron uptake. In addition, we found that P. ureafaciens mVCs inhibited yeast growth mainly through Slt2/Mpk1 MAPK. In nature, plant-deleterious mVCs comprise a large proportion of mVCs and cause growth inhibition in plants. Stomatal closure and ROS accumulation are triggered in plants at the early stage of plant-deleterious mVCs exposure. Prolonged plant-deleterious mVCs exposure induces stomatal closure and callose deposition. The NADPH oxidase RBOHD regulates plant-deleterious mVCs-induced stomatal closure at the early exposure stage, whereas the inducible DAMP receptor THE1-1 contributes to the induction of stomatal closure after prolonged mVCs exposure. In addition, both MKK1 and MKK3 are required in the activation of callose deposition. Auxin response is involved in plant-deleterious mVCs-induced growth inhibition. Furthermore, genes involved in induced systemic resistance (ISR) and antimicrobial metabolites camalexin and coumarin biosynthesis are up-regulated after prolonged plant-deleterious mVCs exposure. MKK1 mediates camalexin biosynthesis gene expression in response to plant-deleterious mVCs, while MKK3 regulates coumarin biosynthesis gene expression. Collectively, our results may provide a deeper understanding of the molecular defense mechanism in the response to microbial volatiles in fungi and plants.

担当: 東京大学大学院理学系研究科・生物科学専攻・生体制御研究室