Diversity And Methods Research Of Vibrio Associated With Seaweeds Surfaces

The diversity of Vibrio associated with surfaces of 4 seaweeds: Gracilaria textorii,Ulva pertusa,Laminaria japonica and Polysiphonia urceolata was studied using different analysis methods.Totally 12 strains were obtained from the surfaces of 4 seaweeds with TCBS media. Strains G1, G2 were from G. textorii, U3 were from U. pertusa, L4, L5, L6 were from L. japonica, P7, P8, P9, P10, P11, P12 were from P. urceolata. They belong to Halomonas (G1, G2) and Vibrio genus (other strains).Enzymatic bioactivity, antibiotic resistance of the 12 strains were studied. The result showed most bacteria isolated can produce starch enzyme and glutin enzyme. Strains G1, G2, U3 are resistant to ampicillin, streptomycin and tetracyclinec.Molecular biology methods were used to study the diversity of 12 strains. The 12 strains obviously formed 4 clusters in phylogeny tree established based on 16S rRNA gene. Each of the strains isolated from the surfaces of G. textorii,U. pertusa,L. japonica formed 1 cluster. Therefore, these strains are specific to seaweeds.Four clusters were formed in phylogeny tree established based on gyrB gene. Strains L4, P9 formed 1 cluster. L6, P8, P10, P11, P12 formed 1 cluster. U3 formed 1 cluster. L5 formed 1 cluster. Strains G1 and G2 can not amplify gyrB gene with gyrB primers, which means that G1 and G2 were far from other strains and the primers designed are specific to Vibrio. Sequences analysis based on gyrB gene gave better resolution than 16S rDNA.16S rDNA restriction fragment length polymorphisms of 12 strains were analyzed with 2 restriction endonucleases. Digestion of 16S rDNA fragment with HinfI enzyme gave rise to 6 restriction patterns for 12 isolates and 4 with SmaI enzyme. Comparing with 16S rDNA and gyrB analysis, RFLP is suitable for differentiation of strains on species level.Finally, diversity of strains was studied with DGGE. The DGGE band of G1, G2 formed 1 band type, U3 formed 1 band type, L5 and L6 formed 1 band type. The result showed that DGGE is suitable for differentiation of strains on genus level.