Ralstonia wenshanensis sp. nov., a novel bacterium isolated from a tobacco field in Yunnan, China

Abstract

A Gram-negative, aerobic, motile with paired polar flagella and rod-shaped bacterium strain (56D2T) was isolated from tobacco planting soil in Yunnan, PR China. Major fatty acids were C16 : 1 ω7c (summed feature 3), C16 : 0 and C18 : 1 ω7c (summed feature 8). The polar lipid profile of strain 56D2T consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid and one unidentified glycolipid. Moreover, strain 56D2T contained ubiquinone Q-8 as the sole respiratory quinone. 16S rRNA gene sequence analysis showed that strain 56D2T was closely related to members of the genus Ralstonia and the two type strains with the highest sequence identities were R. mannitolilytica LMG 6866T (98.36 %) and R. pickettii K-288T (98.22 %). The 16S rRNA gene sequence identities between strain 56D2T and other members of the genus Ralstonia were below 98.00 %. Genome sequencing revealed a genome size of 5.87 Mb and a G+C content of 63.7 mol%. The average nucleotide identity values between strain 56D2T and R. pickettii K-288T, R. mannitolilytica LMG 6866 T and R. insidiosa CCUG 46789T were less than 95 %, and the in silico DNA–DNA hybridization values (yielded by formula 2) were less than 70 %. Based on these data, we conclude that strain 56D2T represents a novel species of the genus Ralstonia , for which the name Ralstonia wenshanensis sp. nov. is proposed. The type strain of Ralstonia wenshanensis sp. nov. is 56D2T (=CCTCC AB 2021466T=GDMCC 1.2886T=JCM 35178T).

Proposal to classify Ralstonia solanacearum phylotype I strains as Ralstonia nicotianae sp. nov., and a genomic comparison between members of the genus Ralstonia

“…The overall G + C content of strain RS T was 67.10 mol%, which is in the range of 63.0–67.3 mol% (avg. 65.86 mol%) for Ralstonia species ( Lu et al, 2022a ). The assembled genome of strain RS T comprised 5,613,239 bp in two replicons: a circular chromosome of 3,618,724 bp and a megaplasmid of 1,994,515 bp.…”

“…The protocol used to analyze the strains’ physiological and chemical characteristics was as described previously ( Lu et al, 2022a ). Culture media, including CPG agar ( Kelman, 1954 ), Kelman’s TZC ( García et al, 2019 ), Luria-Bertani (LB) agar (LA), modified selective medium South Africa (mSMSA) agar ( Elphinstone et al, 1996 ), nutrient agar (NA), potato dextrose agar (PDA), and trypticase soy agar (TSA, BD Difco, Franklin Lakes, NJ, United States), were used to analyze the growth of the strains when incubated at 28°C for 5 days.…”

“…Oxidase activities of the strains were tested using 1% (w/v) tetramethyl- p -phenylenediamine, with Escherichia coli K-12 strain MG 1655 as the negative control and Pseudomonas lijiangensis LJ2 T as the positive control. The production of bubbles detected catalase activity after adding a drop of 3% (v/v) H 2 O 2 ( Lu et al, 2022a ). Cells from the tested strains grown on TSA at 28°C for 48 h were harvested to analyze their fatty acid profile ( Sasser, 1990 ).…”

“…Therefore, the genus Wautersia was created to accommodate the R. eutropha lineage ( Vaneechoutte et al, 2004 ), which has been transferred to the genus Cupriavidus ( Vandamme and Coenye, 2004 ). According to the List of Prokaryotic names with Standing in Nomenclature 1 ( Parte et al, 2020 ), the genus Ralstonia currently comprises seven species with validly published names, including R. mannitolilytica , R. insidiosa , R. pickettii , R. pseudosolanacearum , R. solanacearum , R. syzygii , and R. wenshanensis ( Safni et al, 2014 ; Meier-Kolthoff et al, 2022 ; Lu et al, 2022a ). Recently, we proposed three novel species of the genus Ralstonia , including R. chuxiongensis , R. mojiangensis , and R. soli ( Lu et al, 2023 ).…”

“…Bacteria from the genus Ralstonia have a broad range of niches, including soil, water, plant tissues, and human specimens. The type strains of R. chuxiongensis , R. mojiangensis , R. soli , and R. wenshanensis have been isolated from tobacco planting soils ( Lu et al, 2022a , 2023 ). The type strains of R. mannitolilytica , R. insidiosa , and R. pickettii were described as pathogens in various human infections ( Ralston et al, 1973 ; De Baere et al, 2001 ; Coenye et al, 2003 ).…”