Shaikhul Islam
EXIM Bank Agricultural University Bangladesh (EBAUB), Bangladesh
Title: Endophytic PGPR Isolates from Cucumber Rhizosphere Ensure Enhanced Plant Growth and Suppress Phytophthora Blight of Cucumber
Biography
Biography: Shaikhul Islam
Abstract
Plant growth promoting rhizobacteria (PGPR) are the rhizosphere bacteria that may be utilized to augment plant growth and subdue plant diseases. The objectives of this study were to isolate and characterize PGPR indigenous to cucumber rhizosphere in Bangladesh, and to evaluate their ability to suppress Phytophthora crown rot in cucumber. A total of sixty six isolates were isolated, out of which ten (PPB1, PPB2, PPB3, PPB4, PPB5, PPB8, PPB9, PPB10, PPB11 and PPB12) were chosen based on their in vitro plant growth promoting traits and antagonism of phytopathogens. Phylogenetic analysis of 16S rRNA sequences identified these isolates as new strains of Pseudomonas stutzeri, Bacillus subtilis, Stenotrophomonas maltophilia and B. amyloliquefaciens. The selected isolates produced high levels (26.78 to 51.28 μg mL−1) of indole-3-acetic acid, while significant acetylene reduction activities (1.79 to 4.9 µmole C2H4 mg-1 protein h-1) were witnessed in eight isolates. PGPR treatment of cucumber seeds demonstrated significantly higher germination; enhanced seedling vigor, growth, and N content in root and shoot tissue compared to non-treated control plants. All selected isolates successfully colonized the cucumber roots. Moreover, treating cucumber seeds with these isolates significantly inhibited Phytophthora crown rot caused by Phytophthora capsici, and characteristic morphological alterations in Ph. capsici hyphae that grew towards PGPR colonies were detected. Since these PGPR inoculants had revealed numerous traits advantageous to the host plants, they may be applied in the development of novel, eco-friendly, and effective seed treatments as an alternative to chemical fungicides.