Polyphasic characterization of bacteria obtained from upland rice cultivated in Cerrado soil

Abstract

This work aimed to characterize 20 isolates obtained from upland rice plants, based on phenotypic (morphology, enzymatic activity, inorganic phosphate solubilization, carbon source use, antagonism), genotypic assays (16S rRNA sequencing) and plant growth promotion. Results showed a great morphological, metabolic and genetic variability among bacterial isolates. All isolates showed positive activity for catalase and protease enzymes and, 90% of the isolates showed positive activity for amylase, catalase and, nitrogenase. All isolates were able to metabolize sucrose and malic acid in contrast with mannitol, which was metabolized only by one isolate. For the other carbon sources, we observed a great variability in its use by the isolates. Most isolates showed antibiosis against Rhizoctonia solani (75%) and Sclerotinia sclerotiorum (55%) and, 50% of them showed antibiosis against both pathogens. Six isolates showed simultaneous ability of antibiosis, inorganic phosphate solubilization and protease activity. Based on phylogenetic analysis of the 16S rRNA gene all the isolates belong to Bacillus genus. Under greenhouse conditions, two isolates (S4 and S22) improved to about 24%, 25%, 30% and 31% the Total N, leaf area, shoot dry weight and root dry weight, respectively, of rice plants, indicating that they should be tested for this ability under field conditions.

Consortia of Plant-Growth-Promoting Rhizobacteria Isolated from Halophytes Improve Response of Eight Crops to Soil Salinization and Climate Change Conditions

“…Except in the case of alfalfa and flax, for which there are no previous data, we obtained lower growth for the rest of the crops than that recorded in other studies. Naveed et al [30] observed that an endophyte increased maize shoot and root dry masses up to 48% and 47%, respectively, while these increases were up to 73% and 79% for sunflower and 30% and 31% for rice, respectively, when these crops were inoculated with isolates obtained from their rhizospheres [33,34]. Vestberg et al [35] found that strawberry inoculated with Bacillus subtilis and Pseudomonas fluorescens increased shoot dry weight by 73% and 24%, respectively.…”

High-throughput sequencing-based analysis of the composition and diversity of endophytic bacterial community in seeds of upland rice

“…Compared with traditional rice crops, upland rice has stronger ability of drought resistance and drought tolerance, can adapt to the arid climate, and can greatly save labor and production costs (Kumar and Ladha, 2011;Xia et al 2019). However, up to now, the researches on upland rice mainly focus on the functional genes, genetic diversity and growth promoting microorganisms (Lyu et al 2014;Tuhina-Khatun et al 2015;Ferrari et al 2018;Braga et al 2018;de Sousa et al 2018), and there are few studies on endophytes of upland rice at home and abroad, especially the high-throughput sequencing technology.…”

Screening of beneficial bacteria associated with Calophyllum brasiliense Cambess so as to develop microbial inoculants for agriculture

“…Brazilian savanna soils are generally acidic and deficient of nutrients (Lopes and Guilherme, 2016), and therefore solubilization of inorganic phosphate ability is of great interest for selection of microorganisms with potential to be explored as MI in agriculture. An evaluation of potential phosphate solubilizers of 20 rice root isolates, grown in the Brazilian savanna region, verified that 75% presented solubilizing ability in Pikovskaya medium, and the 16S rRNA gene sequencing analysis revealed that all evaluated isolates showed high similarity with the Bacillus genus (Braga et al, 2018). Phosphorus solubilizing activity is determined by the microbial ability to produce and release organic acids, which through their carboxylic groups chelate the cations bound to phosphorus or decrease the pH, converting phosphorus into soluble forms (Gupta et al, 2012;Awais et al, 2017).…”