BIOLOGICAL-CONTROL OF SHEATH BLIGHT OF RICE - INDUCTION OF SYSTEMIC RESISTANCE IN RICE BY PLANT-ASSOCIATED PSEUDOMONAS SPP

In previous studies on the biological suppression of fungal diseases o f rice with plant-associated rhizosphere bacteria we had reported that production of antifungal antibiotic (afa) by the bacterium is the maj or mechanism involved. In this study we report that the induction of s ystemic resistance in rice by strains of pseudomonads leads to suppres sion of sheath blight. A molecular tracking system (lacZY gene) was us ed to engineer strains of Pseudomonas fluorescens 7-14 and P. putida V 14i. We used the lacZ expression as tracking system to monitor the sur vival and migration of the biocontrol agents. In spite of the absence of bacteria on plant surfaces, the endophytic bacteria present in the stem led to suppression of rice sheath blight caused by Rhizoctonia so lani up to 18%.