Complete genome sequence of RHGG3, a type species of the genus with plant growth-promoting traits and heavy metal resistance.

RHGG3, a novel type species in the genus , originally isolated from rhizosphere soil of watermelon (), has the ability to improve the growth of watermelon seedling and tolerate heavy metals. In vitro, RHGG3 was able to solubilize phosphate (80.56 mg L), produce indole-3-acetic acid (IAA) (11.58 mg L) and was resistant to multiple heavy metals (copper, zinc, cadmium, cobalt and lead). Inoculating watermelon with this strain increased shoot and root length by 22.1% and 43.7%, respectively, and the total number of lateral roots by 55.9% compared to non-inoculated watermelon. In this study, we present the complete genome sequence of RHGG3, which was comprised of a single circular chromosome of 5,659,202 bp with a G + C content of 69.25%. An annotation analysis revealed that the RHGG3 genome contained 5172 coding DNA sequences, 9 rRNA and 55 tRNA genes. Genes related to plant growth promotion (PGP), such as those associated with phosphate solubilization, nitrogen fixation, IAA, phenazine, volatile compounds, spermidine and cobalamin synthesis, were found in the RHGG3 genome. Some genes responsible for heavy metal tolerance were also identified. The genome sequence of strain RHGG3 reported here provides new insight into the molecular mechanisms underlying the promotion of plant growth and the resistance to heavy metals in . This study will be valuable for further exploration of the biotechnological applications of strain RHGG3 in agriculture.