Uttarotai Toungporn, McGenity Terry J, Sutheeworapong Sawannee, Mhuantong Wuttichai, Khongdee Nuttapon, Bovonsombut Sakunnee, Chitov Thararat
Department of Highland Agriculture and Natural Resources, Faculty of Agriculture, Chiang Mai University, Chiang Mai 50200, Thailand.
Environmental Science Research Center, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Curr Res Microb Sci. 2025 Mar 27;8:100382. doi: 10.1016/j.crmicr.2025.100382. eCollection 2025.
Isoprene, a biogenic volatile compound emitted largely by plants, can form greenhouse gases when it reacts with atmospheric radicals. A significant amount of isoprene is absorbed into soil and can be degraded by soil microorganisms, but our understanding of the microbial biodegradation of isoprene in tropical ecosystems remains limited. This study investigated isoprene degradation by soil microbes indigenous to a tropical evergreen forest, focusing on those associated with coffee and tea plants grown as integrated crops and their genome characteristics in relation to their biodegradation capabilities. Following a 96-hour incubation with 7.2 × 10⁵ parts per billion by volume (ppbv) of isoprene, soil samples exhibited degradation levels ranging from 11.95 % to 36.54 %. From these soils, bacterial isolates belonging to the genera and (Actinomycetota) were recovered. These isolates demonstrated high isoprene biodegradation activity (50.3 %-69.1 % over seven days) and carried the gene associated with isoprene metabolism. According to genome analysis, the organization of genes in the cluster was homologous, and the encoded amino acid sequences were highly similar to those of previously known isoprene-degrading members of the same genera. These findings emphasized the contribution of these widespread isoprene-degrading bacterial genera in the biodegradation of isoprene and the role of their isoprene monooxygenases in modulating atmospheric isoprene flux.
异戊二烯是一种主要由植物释放的生物源挥发性化合物，当它与大气自由基反应时会形成温室气体。大量的异戊二烯被吸收到土壤中，并可被土壤微生物降解，但我们对热带生态系统中异戊二烯的微生物降解的了解仍然有限。本研究调查了热带常绿森林原生土壤微生物对异戊二烯的降解情况，重点关注与作为间作作物种植的咖啡和茶树相关的微生物及其与生物降解能力相关的基因组特征。在与体积分数为7.2×10⁵十亿分之一（ppbv）的异戊二烯孵育96小时后，土壤样品的降解水平在11.95%至36.54%之间。从这些土壤中，分离出了属于 属和 属（放线菌门）的细菌。这些分离物表现出较高的异戊二烯生物降解活性（七天内为50.3%-69.1%），并携带与异戊二烯代谢相关的 基因。根据基因组分析， 基因簇中的基因组织是同源的，编码的氨基酸序列与同一属中先前已知的异戊二烯降解成员的氨基酸序列高度相似。这些发现强调了这些广泛存在的异戊二烯降解细菌属在异戊二烯生物降解中的贡献以及它们的异戊二烯单加氧酶在调节大气异戊二烯通量中的作用。
