Isolation and functional characterization of a mVOC producing plant-growth-promoting bacterium isolated from the date palm rhizosphere

Abstract

In this study, various bacterial strains were isolated from date palm (Phoenix dactylifera L.) rhizosphere grown in an orchard with high soil salinity and tested for plant growth-promoting properties by producing microbial volatile compounds (mVOC). An Enterobacter cloacae SQU-2 (SQU-2) bacterial strain was identified, which enhanced the growth of Arabidopsis thaliana Columbia (Col-0) seedlings under both normal and salt stress conditions by producing mVOC. This rhizobacterium also possesses various growth promotion traits such as zinc and phosphorus solubilization, indole acetic acid (IAA), ammonia and siderophore production. Seeing these beneficial traits that the rhizobacterium commands, we sequenced the genome using next-generation sequencing methods to identify the potential growth promotion genes present in this rhizobacterium. Sequence annotation of the genome resulted in identifying various plant growth-promoting gene clusters, including siderophore production and the biosynthesis of mVOC such as 2,3-butanediol and acetoin. The presence of mVOC gene clusters in the genome provides genomic evidence on this bacterium's ability to produce mVOC, through which it enhanced the growth of Arabidopsis seedlings in vitro. The results obtained from this project may open an avenue toward further studies aimed to use this strain in agriculture and to determine the mechanism of plant-microbe interaction, which led to enhancing growth.