Acyl-Butyrolactones Bacteria (microorganisms) Bacterial Proteins Gene Expression Regulation, Bacterial Genes, Reporter Models, Biological Quorum Sensing Rhizobiaceae Rhizobium etli Rhizobium leguminosarum Trans-Activators animal experiment article bacterial protein bacterial spore bacterial strain biological model biosynthesis cloning colony formation controlled study cross coupling reaction downstream processing enzyme activity exopolysaccharide gamma butyrolactone derivative gene expression regulation gene identification gene mutation glucan synthase