Abstract:The study aimed at investigation the effect of the transgenic biocontrol bacteria 308R(pCPP430) on the tomato rhizosphere bacterial communities. Strain 308R (Pantoea agglomerans), an adnascent bacterium isolated from tomato, was a biocontrol bacterium. The recombinant cosmid pCPP430 contained the hrp gene cluster of Erwinia amylovora was transformed into 308R Strain. Transgenic biocontrol bacterium 308R(pCPP430) produced Harpin protein which induce hypersensitive response and disease resistance in plants and, surprisingly, increase plant growth. Two complementary methods, sole-carbon-source utilization tests (SCSU) and ERIC-PCR, were used to compare the characterization of bacterial communities from three groups of tomato roots dipped in sterilized water, 308R suspended liquid and 308R(pCPP430) suspended liquid. The cluster analysis and principal components analysis of the number of colonies from SCSU indicated consistent differences in the rhizosphere of each group. Cluster analysis of SCSU data showed that there were consistent differences in the rhizosphere of each group. The rhizosphere bacteria communities of root dipped with 308R(pCPP 430) and 308R have a relative good replication, but the differences of corresponding replicates in dipped with distilled water was increased by degrees. Cluster analysis of ERIC-PCR fingerprints revealed that most of results (eight in ten) have overlaps between roots dipped in water and those dipped in 308R liquid. The methods used in this study may prove a useful approach for the comparison of bacterial communities.
