Hanaa A. Abo-Kora ., Mahdy, M.E and Galaall, Neveen M.( 2016). Effect of Immobilized PGPRs Bacteria in Different Forms Against Root-Knot Nematodes on Tomato PlantsNature and Science 14(8).
Abstract: Plant growth-promoting rhizobacterium (PGPR) suppresses root–knot nematode Meloidogyne javanica through directly or indirectly effect. In our research four different PGPRs namely Pseudomonas fluorescens, Azotobacter chroococcum, Bacillus polymyxa and Azospirillum brasilense were used at three different formulated types as follows: encapsulated with sodium alginate beads, formulated with mixture of carboxymethyl-cellulose with talcum powder and suspension of culture, to investigate the potential effect against root–knot nematode M. javanica under greenhouse conditions. The viability of the bacterial strains studied by using two polymers; sodium alginate and carboxymethyl cellulose (CMC) in vitro. Viability was measured at four temperatures i.e. - 5, 10, 20 and 30oC after 10, 20, 30 and 40 days from stored (zero time). In vivo treatments classified into two groups; one group inoculated only one from all tested bacteria, whereas the second group inoculated twice after 15 days from the first one with the same treatments. Results showed that significantly effects on nematode and vegetative growth parameters compared to plants treated with nematode alone. All treatment reduced the nematode parameters i.e. number of galls and egg masses/root system between 25-99 % compared to control. The highest reduction percentage in galls number recorded with P. fluorescens at all application forms as ranged between 83-93%, the highest one 91 and 93% recorded with alginate beads types either at one or two inoculation times, respectively. The same trend of results recorded with egg masses as the reduction percentage ranged between 94 and 99%. The highest one also recorded with P. fluorescens alginate beads as ranged between 96 and 99 % at one and two inoculation time, respectively. The lowest effect on nematode parameters observed with A. brasilense at all inoculation forms and times. Moreover, results found that inoculation with encapsulated of all bacterial strains gave a significant increase in rhizosphere enzymatic microbial activities compared to other treatments and control. Also, inoculation with all bacterial strains at all forms and times significantly increased the chemical components i.e. total chlorophyll (a+b), caroteinoids contents as well as total protein content in all treatments compared to control.
Keywords: (PGPRs - Biological control- Meloidogyne javanica- formulation microorganisms- tomato plants (Lycopersicon esculentum L.). )
