Research Article
Yuliar
Abstract
The bacteria isolated from mangrove plants are largely unexplored source for biocontrol agents with the potential to produce biologically active secondary metabolism. Therefore endophytic bacteria for biocontrol agent of bacterial blight (BB) caused by Xanthomonas oryzae isolated from Avicenia alba, A.marina and Bruguiera ghymnorhiza, were explored. Fifty five bacteria strains were isolated from leaves, stems, flowers, fruits, and stalks of the mangrove plants in Bali and Manado, Indonesia. Seven out of the 55 strains, were antibiosis to the growth of Rhizoctonia solani, five strains were antibiosis to the growth of Fusarium oxysporum, while the two others were antibiosis to X. oryzae. None of them was antibiosis to Pythium aphanidermatum and P.ultimum. Eleven consortia of biocontrol agents (BCAs) which consist five of them were tested for suppression of rice BB. Sodium chloride 0.7% was added into the soil in order to know the ability of the BCAs consortia on suppression of BB in saline soil. The objective of this experiment was to screen the consortia of endophytic bacteria isolated from mangrove plants for biocontrol agents of bacterial blight caused by X.oryzae in saline soil. The results showed that BCAs03 reduced the highest BB by 67%, and the lowest was BCAs11 by 22%. FDA hydrolitic in soil on day 29 th, increased by the application of BCAs, except by BCAs11. All of BCAs tested (BCAs01 to BCAs11) were able to increase grain weight.