Profiling of rhizobacteria to alleviate drought stress in oil palm using ribosomal intergenic spacer analysis

During the drought stress period, oil palms experienced increasing ACC substance synthesis converted to ethylene. It decreases root growth and plant tolerance to drought stress. Ethylene production can be controlled by transforming ACC into α-ketobutyrate and ammonia via ACC deaminase (ACCd). This enzyme is produced by bacteria in the plant rooting system when the plant experiences drought stress. This study aimed to characterize ACCd bacteria diversity from selected oil palm progenies with difference responses to drought stress using ribosomal intergenic spacer analysis (RISA). The method used was by isolating bacteria from oil palm root surface using the Dworkin-Foster media enriched with ACC. Bacteria were then isolated, identified molecularly based on 16S rRNA genes, and profiling their population from selected oil palm progenies. The study results show that nine isolates managed to be isolated and characterized based on their morphology. Molecular identification based on their gene bank and phylogenetic analysis revealed that the ACCd bacteria community were divided into three major groups, i.e., Firmicutes, Actinobacteria, and Proteobacteria. Genus Pantoea, Acinetobacter, Pseudomonas, Burkholderia, Kocuria, and Bacillus were identified and could be utilized as bioagents to overcome the drought stress on oil palm crops. Based on the composition of the PCR-RISA fragments, showed that the oil palm rhizosphere of progeny P8 had a higher functional genetic diversity than progeny P1 and P13. Analysis of the similarity pattern of the ACC deaminase producing bacterial community divided 2 large clusters with a similar pattern of up to 69 . © Published under licence by IOP Publishing Ltd.