Multifunctional potential of endophytic and rhizospheric microbial isolates associated with Butia purpurascens roots for promoting plant growth

Abstract

The functional diversity of endophytic and rhizospheric microorganisms associated with the promotion of plant growth includes increased availability of plant nutrients, phytohormone synthesis and phytopathogen suppression. We used the hypothesis that the unknown root and rhizospheric community associated with the Butia purpurascens palm, an endemic species of the Cerrado, could be composed of microbiota with great functional diversity. Thus, the potential of the isolates of this community for four functional traits was evaluated: solubilization of calcium phosphate (CaHPO) and iron phosphate (FePO), synthesis of indoleacetic acid (IAA) and suppression of seed- and fruit-spoilage fungi of B. purpurascens. A total of 166 bacterial isolates, most belonging to the phylum Proteobacteria (94%), and 46 fungal isolates (Ascomycota) were tested. None of the isolates showed the four functional traits tested, but 72% presented two traits (CaHPO solubilization and IAA synthesis). Fifteen fungi (27% of the isolates) presented only the trace for IAA, whereas the capacity for antibiosis was observed in only eight bacteria. CaHPO-solubilization capacity was evidenced by all bacterial isolates and by some fungal isolates. The functional trait for IAA production was present in all isolates, and production levels were significantly above 100 μg mL for some bacteria. Isolates of the genus Bacillus efficiently suppressed the growth of spoilage fungi tested, with relative inhibition rates reaching levels higher than 60% when using Bacillus subtilis. These results attest to the multifunctionality of the endophytic and rhizospheric isolates of B. purpurascens for the promotion of plant growth. This is the first study that sought to identify the root endophytic and rhizospheric microbiota associated with the B. purpurascens palm for the bioprospection of species with functional traits related to the promotion of plant growth, thus opening the way for in vivo tests in plants of commercial or ecological interest.

Microbial Inoculation Improves Growth, Nutritional and Physiological Aspects of Glycine max (L.) Merr.

“…Eight microbial isolates (04 fungi and 04 bacteria), rhizospheric or endophytic, were evaluated; six were previously isolated from H. courbaril (H) [ 34 ], a species widely distributed in the Cerrado biome, and two from B. purpurascens (BP) [ 35 ], an Arecaceae endemic to this biome ( Table 1 ). These strains belong to the culture collection of the Laboratory of Agricultural Microbiology at IFGoiano, Rio Verde campus.…”

Agricultural and Other Biotechnological Applications Resulting from Trophic Plant-Endophyte Interactions

“…It was earlier emphasized that the endophyte microbiota is able to use several mechanisms to stimulate drought stress tolerance in plants [46,80,87], as they can:…”

The synergistic action of <i>Azospirillum brasilense</i> and effective microorganisms promotes growth and increases the productivity of green corn

“…In this context, the development and application of technologies that guarantee productivity and that do not generate negative environmental effects have been stimulated. Researchers that prospect new microbial strains that use functional traits of microorganisms to control phytopathogens or promote plant growth have become very common [1,2,3], aiming at alternatives to pesticide and fertilizer use in crops [4].…”