Abstract

Hypericum silenoides Juss. 1804 is an important medicinal plant used in Mexico, but the bacterial community associated with it is unknown. The bacterial communities in the rhizosphere and roots of H. silenoides were isolated and identified by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR) and ribosomal types were determined by amplified ribosomal rDNA restriction analysis (ARDRA) and 16S rRNA gene sequences. Sixty-six strains were obtained from roots of H. silenoidesand 37 were isolated from the rhizosphere. ERIC fingerprinting distinguished 63 genetic patterns with 44 being unique and the remaining 19 containing 59 strains. Eighteen representative strains were distinguished with ARDRA analysis. 16S rRNA gene sequence analysis revealed that the bacteria isolated from the roots and rhizosphere of H. silenoides belonged to the genera Acinetobacter, Enterobacter, Pseudomonas, Sphingobium, Stenotrophomonas, Agrobacterium, Pantoea and Serratia. The largest number of isolates (30) belonged to the genus Agrobacterium. Richness and diversity of bacteria was higher on the roots than in the rhizosphere of H. silenoides.

Key words: Agrobacterium, endophytic bacteria, 16S rDNA, amplified ribosomal rDNA restriction analysis (ARDRA), enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR), phylogeny.