Fusariosis control in black pepper plants with bacterial endophytes: Survival and morphophysiological responses

Eight endophytic bacteria from black pepper seedlings were tested under gre enhouse conditions aiming to control Fusarium solani f sp. piperis and to e valuate some morphophysiological responses in plants treated with the bioco ntrol agents. Four-month old plants had their roots treated with the bacter ial suspensions(10(9) cfu mL(-1)) for 10 minutes and were planted in pots c ontaining soil artificially infested with the pathogen (0.25%). The experim ental design was completely randomized, with three replications to evaluate photosynthetic behavior, and biomass production and allocation, and five r eplications to evaluate plant mortality. Evaluations were made 120 days aft er the establishment of the experiment. The isolate B0 (Methylobacterium ra diotolerans) significantly reduced seedling mortality by fusariosis. No sig nificant effect in seedling mortality reduction could be detected for the o ther bacterial isolates. In the absence of the pathogen, M, radiotolerans a cted as a plant growth promoter. The application of the bacterial endophyte s had no effect on the instantaneous photosynthetic rate, with the exceptio n of B6, that had a negative effect. Plants treated with M. radiotolerans a llocated carbon preferentially to the above ground tissues.