Isolation of Plant Growth-Promoting Bacteria from Hilly Areas of Sheikh Badin, Khyber-Pakhtunkhwa Province, Pakistan

Abstract

Plant growth-promoting bacteria are playing pivotal role in agriculture field and such organisms are the main focus of the researchers. This study was designed to explore the diversity of bacteria from the Sheikh Badin hilly areas of Khyber-Pakhtunkhwa, Pakistan. Total twelve (12) bacterial strains IOM-1 to IOM-12 were isolated using culture dependent method.  The isolated bacterial strains were able to grow on T5 medium, R2A agar, TSA, and nutrient agar media. Optimum growth was recorded at 30-45 °C and at pH 7.0-7.2. All the isolated organisms were Gram-stain-negative, aerobic and small rod-shaped. Strains were positive for oxidase and catalase activities. Sequence similarities of 16S rRNA gene showed, that isolated strains were belonging to the genus Microvirga (97.93-100 %) and the closest neighbors were M. jeongseonensis, M. terrestrus, M. calopogonii, M. splendida, M. guangxiensis, M. vignae, M. tunisiensis and M. zambiensis. According to phylogenetic analysis result, isolates were forming eight clades with their closest reference type strains. Organisms IOM-6, IOM-8, IOM-10, IOM-11, and IOM-12 were found to have nitrogen fixation capabilities, which revealed that these isolated bacterial strains will play an important role in plant growth promotion.

Keywords: Plant-Growth-Promoting Bacteria (PGPB), Sheikh Badin hilly areas of KPK, Pakistan, Microvirga, 16S rRNA gene, Phylogenetic analysis