Metataxonomics 16S rDNA of maize rhizospheric soil with seed bacterization with Bacillus thuringiensis RZ2MS9 WT and mutant daiiA

The plant growth-promoting bacteria (PGPB) <em>Bacillus thuringiensis</em> (Bt) RZ2MS9 have been described as a potential bioinoculant for maize (<em>Zea mays</em> L.). Quorum quenching (QQ) is an important system that has evolved in some bacteria as a competitive advantage for niche colonization. The <em>aiiA</em> gene, a homoserine lactonase involved in QQ, was identified in Bt RZ2MS9 genome and the ability to degrade quorum sensing (QS) molecules was validated through a QQ biosensor assay. The knockout of RZ2MS9 <em>aiiA</em> was performed using the CRISPR-Cas9 system, confirming this gene function <em>in vitro</em>. The influence of QQ activity of RZ2MS9 for maize growth promotion and its implications in the persistence of the PGPB in the microbial community were investigated in a greenhouse experiment. Maize seeds were inoculated with the strains RZ2MS9 WT and RZ2MS9 <em>ΔaiiA</em> and sowed in pots. Twenty five days after sowing (DAS), samples of rhizospheric soil were collected for total DNA extraction and 16S rDNA sequencing by Illumina MiSeq (2x250 bp) and plant phenotypic traits were evaluated. Our aim was to investigate whether the ability of RZ2MS9 interfering in QS communication is relevant for the establishment of the PGPB in a native microbial community and, consequently, for plant growth promotion.