Abstract:
In this study, we investigated the role of quorum sensing (QS) in expression of the Sinorhizobium
meliloti cell division gene ftsZ2 in free-living cells and within nodules of its host plant, Medicago
truncatula. Using a ftsZ2 promoter reporter fusion, we were able to track the expression of this gene in
wild-type S. meliloti cells and QS mutant backgrounds in planta. Our findings revealed that expression
of ftsZ2 in free-living cells was changed or reduced in sinI mutant cells compared with wild-type cells
while expression in planta was substantially higher in the absence of sinI. The results further clarify the
involvement of quorum sensing in the control of bacterial cell division during the symbiosis in planta.