Genetic and Phenotypic Diversity of Plant Growth Promoting Rhizobacteria Isolated from Sugarcane Plants Growing in Pakistan

Abstract

Bacteria were isolated from roots of sugarcane varieties grown in the fields of Punjab. They were identified by using API20E/NE bacterial identification kits and from sequences of 16S rRNA and amplicons of the cpn60 gene. The majority of bacteria were found to belong to the genera of Enterobacter, Pseudomonas, and Klebsiella, but members of genera Azospirillum, Rhizobium, Rahnella, Delftia, Caulobacter, Pannonibacter, Xanthomonas, and Stenotrophomonas were also found. The community, however, was dominated by members of the Pseudomonadaceae and Enterobacteriaceae, as representatives of these genera were found in samples from every variety and location examined. All isolates were tested for the presence of five enzymes and seven factors known to be associated with plant growth promotion. Ten isolates showed lipase activity and eight were positive for protease activity. Cellulase, chitinase, and pectinase were not detected in any strain. Nine strains showed nitrogen fixing ability (acetylene reduction assay) and 26 were capable of solubilizing phosphate. In the presence of 100 mg/l tryptophan, all strains except one produced indole acetic acid in the growth medium. All isolates were positive for ACC deaminase activity. Six strains produced homoserine lactones and three produced HCN and hexamate type siderophores. One isolate was capable of inhibiting the growth of 24 pathogenic fungal strains of Colletotrichum, Fusarium, Pythium, and Rhizoctonia spp. In tests of their abilities to grow under a range of temperature, pH, and NaCl concentrations, all isolates grew well on plates with 3% NaCl and most of them grew well at 4 to 41 o C and at pH 11.

A comprehensive study on algal–bacterial communities shift during thiocyanate degradation in a microalga-mediated process

“…Although the relevant interaction mechanisms are not clearly identified in this study, the sequencing results obtained in the present work suggest that there may be positive symbiotic interactions between Rhizobium and microalgae in the system. Furthermore, the loads of other rhizobacteria, including Devosia, Exiguobacterium, Mesorhizobium, Ochrobactrum, Pannonibacter, and Sphingopyxis (Dias et al, 2009;Mehnaz et al, 2010;Paulucci et al, 2013) also increased during microalgal growth in this study (Supplementary Table S4). …”

Uncovering potential ‘herbal probiotics’ in Juzen-taiho-to through the study of associated bacterial populations

“…36 Many strains in this genus are known as rhizobacteria with plant growth-promoting activities. 37–39 The current study raised a possibility that some Rahnella species are enriched in A. sinensis and contribute to its immunostimulatory activity. Further studies are underway to characterize the bacteria in A. sinensis and other herbs in JTT.…”

Cultivable Nitrogen Fixing Bacteria from Extremely Alkaline-Saline Soils

“…Paenibacillus spp. are ubiquitous, and frequently isolated from the rhizosphere of maize, wheat, sugarcane, and pioneer plants growing on mine tailings [28] [45]- [47]. Nitrogen fixing species are also characterized by their capacity to produce phytohormones, solubilize phosphorous and control the access of phytopathogens in plants [45] [46] [48] [49].…”