Diversity of endophytic bacteria from Piper spp. with antagonistic property against Phytophthora capsici causing foot rot disease in black pepper ( Piper nigrum L.)

摘要

Endophytes, especially bacteria, which inhabit healthy plant tissues without causing any damage to the host, have immense potential as biological control agents against plant diseases. Though the presence of antagonistic endophytic bacteria have been reported from black pepper ( Piper nigrum L.), no information about antagonistic bacterial endophytes of Piper colubrinum , a wild exotic relative of black pepper resistant to the foot rot pathogen, are available. The culturable bacterial endophytic communities associated with Piper nigrum and Piper colubrinum were isolated and screened for antagonistic potential against Phytophthora capsici . Out of the 47 bacterial endophytic isolates obtained, 12 showed in vitro antagonism against P. capsici . The isolates were identified based on biochemical and molecular characterization. Phylogenetic analysis of 16S rRNA gene sequences showed considerable diversity of antagonistic bacterial endophytes present in Piper spp. It was observed that Bacillus spp. were predominant among the endophytes that have antagonistic activity against P. capsici . An endophytic bacterial isolate belonging to Rhizobium sp that showed in vitro antagonism against P. capsici was also obtained from P. colubrinum root tissues.