Methane Oxidation Potentials of Rice-associated Plant Growth Promoting Methylobacterium Species

• Published in: Hanguk hwangyeong nonghak hoeji Vol. 41; no. 2; pp. 115 - 124
• Main Authors: Kang, Yeongyeong, Walitang, Denver I., Seshadri, Sundaram, Shin, Wan-Sik, Sa, Tongmin
• Format: Journal Article
• Language: English
• Published: 한국환경농학회 01.06.2022
• Subjects: 농학
• ISSN: 1225-3537; 2233-4173
• DOI: 10.5338/KJEA.2022.41.2.15

BACKGROUND: Methane is a major greenhouse gas at-tributed to global warming partly contributed by agricul-tural activities from ruminant fermentation and rice pad-dy fields. Methanotrophs are microorganisms that utilize methane. Their unique metabolic lifestyle is enabled by enzymes known as methane monooxygenases (MMOs) catalyzing the oxidation of methane to methanol. Rice ab-sorbs, transports, and releases methane directly from soil water to its stems and the micropores and stomata of the plant epidermis. Methylobacterium species associated with rice are dependent on their host for metabolic sub-strates including methane. METHODS AND RESULTS: Methylobacterium spp. isolated from rice were evaluated for methane oxidation activities and screened for the presence of sMMO mmoCgenes. Qualitatively, the soluble methane mono-oxygenase (sMMO) activities of the selected strains of Methylobacterium spp. were confirmed by the naphthalene oxidation assay. Quantitatively, the sMMO activity ranged from 41.3 to 159.4 nmol min--1 mg of protein-1. PCR-based amplification and sequencing confirmed the presence and identity of 314 bp size fragment of the mmoC gene showing over 97% similarity to the CBMB27 mmoC gene indicating that Methylobacterium strains be-long to a similar group. CONCLUSION(S): Selected Methylobacterium spp. contained the sMMO mmoC gene and possessed methane oxidation activity. As the putative methane oxidizing strains were isolated from rice and have PGP properties, they could be used to simultaneously reduce paddy field methane emission and promote rice growth. KCI Citation Count: 0