ARTICLE | doi:10.20944/preprints202207.0157.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: Methylococcaceae; methanotroph; Indian rice field; Methylmonas; novel species
Online: 11 July 2022 (09:56:06 CEST)
An aerobic methanotroph, strain Kb3T, was isolated from a rhizospheric soil sample collected from a tropical Indian rice field. The cells were motile, Gram-negative bacilli, formed pink colonies and pink turbid/pellicles in the liquid medium. Biochemical characteristics showed that strain Kb3T utilised only methane and methanol as its sole carbon and energy sources. The isolate's 16S rRNA gene sequence expressed 99.52% similarity to the recently described valid species Methylomonas fluvii EbB (Mmf), with 92% query cover. But examining the genome similarity between Kb3 and EbB, a DDH value of 44.20% [41.6 - 46.7%] and an Ortho-ANI value of 91.48 was observed that were below the current cut-off values for species differentiation. Also, the 16S rRNA gene phylogeny and the phylogenomic analysis branched the two species separately. The major fatty acid in Methylomonas sp. Kb3 was C14:0, followed by C16:1 ω5c. The genome sequence revealed the size of strain Kb3 is 5.1 Mb, with the G + C content of 51.8%. Strain Kb3T shared the closest relatedness with Methylomonas sp. LW13 reveals a 99.66% 16S rRNA gene similarity, an Ortho-ANI value of 97.9%, a DDH value of 87.3%, and a close branching in the phylogenomic tree Kb3 and LW13 together form a new species. The genomic and phylogenetic distinction between species Mmf and strain Kb3 supports Kb3T to be described as a novel species within the genus Methylomonas, with the proposed name, Methylomonas aquatica sp. nov. (Mma) and the type strain being Kb3T (=MCC 4012, =JCM 33634, =KCTC 72521).