Isolation and characterization of Metapseudomonas agri sp. nov. and Metapseudomonas agrisoli sp. nov. isolated from the rhizosphere soil of agricultural fields

Two novel strains MAHUQ-55 T and MAHUQ-62 T were isolated from the rhizosphere soils of rice and pumpkin, respectively. Both strains were Gram-negative, catalase- and oxidase-positive, motile and rod-shaped. Strains MAHUQ-55 T and MAHUQ-62 T grew at 10–45 °C and 10–40 °C and pH 5.5–10.0 and 5.0–10.0 and tolerated 0–3.0% and 0–4.0% (wt/v) NaCl, respectively. Both strains hydrolysed l -tyrosine, Tween 20 and Tween 80. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains MAHUQ-55 T and MAHUQ-62 T belong to the genus Metapseudomonas , showing the highest sequence similarities to Metapseudomonas furukawaii KF707 T (98.9%) and Metapseudomonas lalkuanensis PE08 T (99.4%), respectively. The genome sizes of strains MAHUQ-55 T and MAHUQ-62 T were 6,415,999 and 6,038,011 bp, respectively, with DNA G+C contents of 65.1 and 63.0 mol%. The average nucleotide identity (ANI) and digital DNA–DNA hybridization (dDDH) values between the two strains and their closest relatives were below the species delineation thresholds (ANI: 95–96%; dDDH: 70%). Both strains exhibited ubiquinone 9 as the predominant respiratory quinone and C 12 : 0 , C 16 : 0 , summed feature 3 (C 16 : 1 ω 7c and/or C 16 : 1 ω 6c) and summed feature 8 (C 18 : 1 ω7c and/or C 18 : 1 ω 6c) as major fatty acids. Based on dDDH, ANI value, genotypic analysis and chemotaxonomic and physiological data, strains MAHUQ-55 T and MAHUQ-62 T represent two novel species within the genus Metapseudomonas . Therefore, the names Metapseudomonas agri sp. nov. (type strain MAHUQ-55 T =KACC 22002 T =CGMCC 1.18516 T ) and Metapseudomonas agrisoli sp. nov. (type strain MAHUQ-62 T =KACC 22243 T =CGMCC 1.18999 T ) are proposed.