AUTHOR=Jiang Zhu-Ming , Deng Yang , Han Xue-Fei , Su Jing , Wang Hao , Yu Li-Yan , Zhang Yu-Qin 

TITLE=Geminicoccus flavidas sp. nov. and Geminicoccus harenae sp. nov., two IAA-producing novel rare bacterial species inhabiting desert biological soil crusts

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1034816

DOI=10.3389/fmicb.2022.1034816

ISSN=1664-302X

ABSTRACT=<p>Two Gram-staining negative strains (CPCC 101082<sup>T</sup> and CPCC 101083<sup>T</sup>) were isolated from biological sandy soil crusts samples collected from Badain Jaran desert, China. Both isolates were heterotrophic phototroph, could produce indole-3-acetic acid. The 16S rRNA gene sequences of these two strains were closely related to the members of the family <italic>Geminicoccaceae</italic>, showing high similarities with <italic>Geminicoccus roseus</italic> DSM 18922<sup>T</sup> (96.9%) and <italic>Arboricoccus pini</italic> B29T1<sup>T</sup> (90.1%), respectively. In phylogenetic tree based on 16S rRNA gene sequences, strain CPCC 101082<sup>T</sup> and CPCC 101083<sup>T</sup> formed a robust distinct clade with <italic>Geminicoccus roseus</italic> DSM 18922<sup>T</sup> within the family <italic>Geminicoccaceae</italic>, which indicated that these two isolates could be classified into the genus <italic>Geminicoccus</italic>. The growth of strain CPCC 101082<sup>T</sup> occurred at 15–42°C and pH 4.0–10.0 (optima at 28–37°C and pH 6.0–8.0). The growth of strain CPCC 101083<sup>T</sup> occurred at 4–45°C and pH 4.0–10.0 (optima at 25–30°C and pH 6.0–8.0). The major cellular fatty acids of CPCC 101082<sup>T</sup> and CPCC 101083<sup>T</sup> contained C<sub>18:1</sub><italic>ω</italic>7<italic>c</italic>/C<sub>18:1</sub><italic>ω</italic>6<italic>c</italic>, cyclo-C<sub>19:0</sub><italic>ω</italic>8<italic>c</italic>, and C<sub>16:0</sub>. Q-10 was detected as the sole respiratory quinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, phosphatidylethanolamine, an unidentified phospholipid and an unidentified aminolipid were tested in the polar lipids profile. The genomes of the two isolates were characterized as about 5.9 Mbp in size with the G + C content of nearly 68%. The IAA-producing encoding genes were predicated in both genomes. The values of average nucleotide identity were 80.6, 81.2 and 92.4% based on a pairwise comparison of the genomes of strains CPCC 101082<sup>T</sup> and CPCC 101083<sup>T</sup> and <italic>Geminicoccus roseus</italic> DSM 18922<sup>T</sup>, respectively. On the basis of the genotypic, chemotaxonomic and phenotypic characteristics, the strains CPCC 101082<sup>T</sup> (=NBRC 113513<sup>T</sup> = KCTC 62853<sup>T</sup>) and CPCC 101083<sup>T</sup> (=NBRC 113514<sup>T</sup> = KCTC 62854<sup>T</sup>) are proposed to represent two novel species of the genus <italic>Geminicoccus</italic> with the names <italic>Geminicoccus flavidas</italic> sp. nov. and <italic>Geminicoccus harenae</italic> sp. nov.</p>