Abstract:
Edible seaweed - Caulerpa lentillifera is being cultivated along the coast
of Khanh Hoa province, Vietnam, and makes a relatively large
contribution to the economic development of this region. Bacterial strains
originating from marine sources such as those associated with seaweed
and hard coral were screened for properties of promote plant growth with
the capacity of indole-3-acetic acid (IAA) - a phytohormone belonging to
auxin group, the phosphate solubilization ability and antibacterial activity
of IAA-producing strains were also performed in this study. Robust
strains were identified by morphological methods with biochemical tests
and analysis of 16s RNA sequences. Isolate RN06 produced high amounts of IAA, utilized inorganic phosphate, and inhibited Bacillus subtilis
ATCC6633, Escherichia coli 0157, and Serratia marcescens PDL100.
The IAA producer HRA5 isolated from hard coral demonstrated the
ability to solubilize phosphate and exhibited antibacterial activity against
B. subtilis. Morphological analysis and 16sRNA sequencing showed that
isolate RN06 was the closest strain to Bacillus amyloliquefaciens and
HRA5 was linked to Pseudomonas sp. This is the first report of isolated
bacteria from seaweed and corals from the Vietnamese sea served as
potential strains for further research of the application of biological
inoculants specifically for seaweed farming.