Plant Growth Promoting Endophytic Bacteria from Mangrove Plants in South West Coast of Kerala
The use of micro organisms as soil inoculants to promote plant growth and to protect the plant from pests and diseases is an emerging area in sustainable agricultural practices. Plant Growth Promoting Bacteria (PGPB) may promote plant growth directly by facilitating nutrient acquisition or modulating plant hormone levels and indirectly by decreasing the inhibitory effects of various pathogenic agents. Plant Growth Promoting Rhizobacteria have been reported to enhance plant growth by a variety of mechanisms. Endophytes or micro organisms living within the tissue of a plant as endosymbionts, without causing symptoms of disease also contribute to plant growth along with rhizospheric bacteria. In the present study endophytic bacteria isolated from mangrove plants were screened for their plant growth promoting traits like phosphate solubilisation, nitrogen fixation, ammonia production, Indole Acetic Acid production, ACC deaminase production, HCN production and siderophore production. All isolates exhibited at least one plant growth promoting trait. Most of them exhibited a combination of different traits. Out of 15 isolates, six exhibited phosphate solubilization ability. N2 fixing ability and ammonia production was shown by nine isolates. IAA production was very common and 14 isolates were able to produce IAA in different concentrations. Six isolates were found to produce ACCdeaminase. Antagonistic properties like HCN production and siderophore production were shown by 13 isolates and three isolates respectively. Thus the endophytes screened were found to be contributing to plant growth and survival and hence hold potential to be utilized as soil inoculants or in other agro industrial applications. Field trials with these isolates and their characterization need to be further researched on.