Culture Dependent Analysis of Bacterial Diversity Associated with Malus domestica (B.)

Abstract

The surfaces of fresh fruits harbour a wide variety of bacterial communities, but less is known about their type. The main objective of the current study was to analyze the bacterial diversity isolated from apple (Malus domestica (B.). Samples collected from different locations of Lahore; Pakistan were processed by direct plate count method using 0.1 % peptone water. Sampling was done periodically four times from moderate to cold temperatures (September, October, November and December). Almost 60 strains isolated were characterized based on morphological and biochemical characterization. A total of 24 screened bacterial strains were identified by using 16S rRNA gene sequencing. Results revealed that these bacteria belonged to Bacillus, Marichromatium, Staphylococcus and Enterobacteriaceae genera. The antibiotic susceptibility profile of bacterial strains was assessed against Gentamycin (10 µg), Streptomycin (10µg), Tetracycline (30 µg) and Chloramphenicol (30 µg). All bacterial strains were resistant to Tetracycline. Colorimetric estimation of bacterial auxin manifested significant levels of auxin biosynthesis. B. aerius, Enterobacter cloacea, Klebsiella pneumoniae and B. marisflavi exhibited production of 62.10 µg/ml, 37.67 µg/ml, 126.67 µg/ml, 66.38 µg/ml, 20.53 µg/ml conc. of auxin, respectively. The presence of E. cloaceae, B. cereus, K. pneumoniae on the surface of apple fruit manifests that it was contaminated with different types of potential pathogenic bacterial strains. Albeit bacterial auxin production suggests that they may be beneficial for agricultural productivity.