Managing gene expression in Pseudomonas simiae EGD-AQ6 for chloroaromatic compound degradation

Abstract

Pseudomonas simiae EGD-AQ6 showed utilization of chloroaromatic compound, 2-4dichlorophenoxyacetic acid (2,4-D) e ciently in its bio lm phenotype. The differential rates of accumulation of intermediate metabolite 4-chlorocatechol (4-CCA) were signi cant in both planktonic and bio lm phenotypes; also increased number of bio lm cells were observed during 2,4-D utilization.Interestingly, response surface analysis demonstrated the combined positive effects of 2,4-D degradation and 4-CCA accumulations. Also, gene expression pro les showed signi cant up-regulation of degradative and bio lm genes (particularly pellicle forming genes) in the bio lm phenotypes than their planktonic counterparts, thereby con rming occurrence of phenotype variations of Pseudomonas simiae EGD-AQ6 during chloroaromatic degradation. Furthermore, the sequence similarity of the 2-4-D catabolic genes and bio lm forming proteins (pel ABCDEFG and pga ABCD) which are responsible for building carbohydrate rich extracellular matrix, were signi cant with the respective organisms as revealed through genome analysis. This is the rst report, which endorses this Pseudomonas simiae species to be unique in chloroaromatic degradation through phenotype variation, thereby proving as a potential candidate in the improvement of bioremediation technologies.