Soil inoculation with Pseudomonas aeruginosa 3mT eliminates the inhibitory effect of 3-chloro- and 4-chlorobenzoate on tomato seed germination

The effects of 3-chloro- and 4-chlorobenzoate (3-CBA, 4-CBA) on the germination of different crop seeds were tested. Brinjal (egg plant) and tomato seeds were highly sensitive to 200 mg l−1 of either 3-CBA or 4-CBA and showed marked reduction in germination percentage and seedling vigour index. A number of abnormalities were observed in all seedlings at higher concentrations of the chemicals. At 400 μg ml−1 germination of tomato seeds was completely inhibited on moist filter paper. A marked reduction in protease activity was observed in germinating tomato seeds treated with these chemicals. Inoculation of 3-CBA- or 4-CBA-treated soil with a chlorobenzoate-degrading Pseudomonas aeruginosa 3mT (1 μg g−1 soil) completely protected the tomato seeds and seedlings. The inoculated bacterial strain grew well in the soil utilizing the chlorobenzoates and developed 1×109 and 8×108 cfu g−1 in 3-CBA- and 4-CBA-treated soil, respectively, as against of 3×107 cfu g−1 in the absence of these chlorobenzoates.