Species And Functional Diversity Of Rhizobacteria Of Rice Plant In The Coastal Soils Of Indonesia

Rhizobacteria are important components of soil and directlyor indirectly influence the soils quality and plant growth formaintaining adequate plant nutrition and reducing the negativeenvironmental effects of fertilizers. Applying high dose ofchemical fertilizers in most of rice fields in the coastal areascould reduce the quality of the soil in the long time. There arefew studies addressed to verify the species and functionaldiversity of cultivable rhizobacteria associated with rice plantin the coastal soils. The objective of the study was to verify thespecies and functional diversity of rhizobacteria isolated fromthe coastal soils of two rice production areas of Subang andIndramayu, West Java. Special focus was given to verifyphosphate solubilization, nitrogen fixation, IAA and cellulaseproduction of the selected 78 strains of rice rhizobacteriaisolated from the coastal paddy field, as well as taxonomicalanalyses based on 16S rRNA. The results showed that among 78bacterial isolates from the coastal paddy field, mostly werebelonging to the Firmicutes, most of them affiliated withgenera Bacillus, 75 strains produced IAA, 32 strains fixednitrogen, 37 strains solubilized phosphate and 33 strainsproduced cellulase. Several strains of the rhizobacteria werecapable of producing plant growth promoting substances(PGPR), alone or in combination, such as IAA, fixing nitrogen,solubilizing phosphate, and producing cellulase. Taking all ofthese diverse PGPR characteristics into account, it is clear thatthe 78 identified isolates have great potential for improvingsaline soils of the coastal paddy fields in Indonesia.[Keywords: Rhizobacteria, functional diversity, rice plant, coastalsoil] Indonesian Journal of Agriculture Science Vol 16 No. 1. April 2015, 39-50