Genome features and metabolic properties of Ca. Methylomicrobium oryzae, the first Methylomicrobium member isolated from rice fields

Abstract

Abstract Methanotrophs represent a group of bacteria that oxidize methane and are therefore environmentally very important. The cultivation of methanotrophs poses a challenge due to their specific cultivation conditions. Rice fields are important habitats where methanotrophs play a vital role in methane mitigation. Very few laboratories in the world culture methanotrophs. We recently cultured Methylomicrobium strain RS1 and reported it as a member of putative novel species (Ca. Methylomicrobium oryzae) using draft genome-based ANI and DDH parameters [1]. In the present work, we present the polyphasic characterization of this novel species which is the first species of Methylomicrobium being reported from rice fields. Ca. Methylomicrobium oryzae is the first cultured methanotroph to be described from rice field habitats and could be an important player in these ecosystems and awaits further studies. Methylomicrobium sequences have been reported from rice fields but there were no reports of cultivation of members from this group, and ours was the first report. The culture was difficult and slow in growth and could not be cryopreserved. Therefore, it cannot be deposited in two international culture collections and has to be maintained as a live culture in our laboratory. In the present study, we describe the biochemical characteristics, metabolic properties, and salient genome features of Ca. Methylomicrobium oryzae strain RS1.