study plant growth promoting bacillus isolates in tomato root colonization and meloidogyne javanica population reduction

in this study, high biocontrol potentially bacillus isolates, against root knot nematode were evaluated from viewpoint of biofilm formation and root colonization in vitro. among 139 bacillus isolates from tomato rhizosphere of several regions of razavi khorasan, 15 strains which show more ability to prevent egg hatch and cause larvae mortality of meloidogyne javanica, were tested in biofilm assay. based on biofilm amount, six isolates including md6.5, md1.8, bag2.13, n2.2, ft1.7 and b. subtilis were selected for pot experiments and colonization assay. according to our findings, isolates md1.8, md6.5 with 75 and 99 % larvae mortality, in vitro maximum biofilm production, tomato root colonization with 106 and 2x106 cfu/ml, reducing disease symptoms in comparison to infected control and development of tomato growth parameters, have been suggested as powerful bacillus isolates in field conditions. it seems, efficient colonization of tomato root, using bacillus strains, has an important role in plant protection of root knot agent.