Genetic diversity and growth promoting characteristics of diazotrophic bacteria isolated from 20 genotypes of Brachiaria spp.

The occurrence of rhizobacteria from Paspalum genotypes and their effects on plant growth

“…Bacterial strains isolated from roots (7) and rhizospheric soil (2) of Paspalum genotypes BGP 098, BGP 343, BGP 318, BGP 343, BGP 215, and BGP 032 produced IC ranged from 2.79 to 36.62 μg of IAA mL -1 OD -1 , all genotypes are closely related to genera Paraburkholderia, Bacillus, Enterobacter, Pseudomonas, and Acinetobacter. The production of indolic compounds by PGPR agrees with reports of other authors (Cássan et al, 2013;Chaves et al, 2015;Ribeiro et al, 2020), who found values of indole production in vitro ranging from 10 to 50 IAA μg mL -1 OD -1 for PGPR isolated from sugarcane and Brachiaria. Exogenous indole compounds are known to play a role in root development (Costacurta and Vanderleyden, 1995;Patten and Glick, 1996) and act during plant drought stress (Nabti et al, 2010).…”

“…The greatest number of rhizobacteria was found in roots of P. notatum genotype (BGP 318); however, the largest number of bacterial isolates was detected in P. regnellii genotype (BGP 215) (Table 1). Ribeiro et al (2020) observed similar results evaluating 20 genotypes of Brachiaria in semisolid NFb and LGI media, where a great bacterial population did not correlate with a larger number of isolates.…”

“…However, only 130 isolates remained viable after storage in the appropriate medium. The PGPR population was also variable for many grass genotypes, including elephant grass (Videira et al, 2012), Brachiaria (Ribeiro et al, 2020), sugarcane (Reis Jr. et al, 2000), and Bahia grass (Dobereiner, 1966).…”

“…Soil bacteria benefit soil properties and plants and can be an alternative N source in tropical grasslands. Many bacterial genera associated to various managed grassland ecosystems are classified as diazotrophic bacteria, belonging to genera Azospirillum, Azotobacter, Rhizobium, Bacillus, Pseudomonas, and others (Antunes et al, 2019;Döbereiner, 1966;Ribeiro et al, 2020;Souza et al, 2017).…”

“…Plant Growth Promoting Rhizobacteria (PGPR) fix N, enhance production of different enzymes that stimulate plant development, aid solubilization of nutrients, and increase production of different phytohormones and other metabolites, such as siderophores, which are antagonistic to pathogens (Backer et al, 2018;Ribeiro et al, 2020).…”