Plant growth promoting bacteria in Brachiaria brizantha

Abstract

Brachiaria brizantha is considered one of the preferred fodders among farmers for having high forage yield and large production of root mass. The association of beneficial bacteria with these grasses can be very valuable in the recovery of the pasture areas with nutritional deficiency. With the aim of studying this possibility, we carried out the sampling of soil and roots of B. brizantha in three areas (Nova Odessa-SP, São Carlos-SP and Campo Verde-MT, Brazil). Seventy-two bacterial strains were isolated and used in tests to evaluate their biotechnological potential. Almost all isolates presented at least one positive feature. Sixty-eight isolates produced analogues of indole-3-acetic acid, ten showed nitrogenase activity when subjected to the method of increasing the concentration of total nitrogen (total N) in the culture medium and sixty-five isolates showed nitrogenase activity when subjected to acetylene reduction technique. The partial sequencing of 16S rRNA of these isolates allowed the identification of seven main groups, with the prevalence of those affiliated to the genus Stenotrophomonas (69 %). At the end, this work elected the strains C4 (Pseudomonadaceae) and C7 (Rhodospirillaceae) as promising organisms for the development of inoculants due to their higher nitrogenase activity.

The Resurrection Plant Tripogon Spicatus (Poaceae) Harbors a Diversity of Plant Growth Promoting Bacteria in Northeastern Brazilian Caatinga

“…isolate ESA 0014. These results corroborate results from other studies, in which efficient diazotrophic and phytohormone producing bacteria were isolated from cultivated (Kuss et al, 2007;Ferrara et al, 2012;Silva et al, 2013;Santos et al, 2015) and wild species (Doty et al, 2009;Jha et al, 2012).…”

“…In the present study, among the 16 bacterial isolates evaluated, only two were not related to Enterobacteriaceae or Firmicutes, and they were classified as Rhizobium and stenotrophomonas. Both genera are known to include PGPB associated with non-legume crops and wild species (Ferrara et al, 2012;Jha et al, 2012;Silva et al, 2013). …”

“…The diazotrophic capacity of the bacterial isolates grown in semi-solid medium was assessed through quantification of total N content after pellicle formation of the putative diazotrophic bacteria (Kuss et al, 2007;Silva et al, 2013). The bacteria were grown in vials containing 10 mL of BMGM semi-solid medium at 28 °C in a growing chamber for 7 days.…”

Diazotrophic Bacterial Community of Degraded Pastures

“…Based on the criteria for pasture degradation established by Stoddart et al [18] and in the application time of the N, three areas were selected for the collection of plant and rhizospheric soil samples to evaluate the bacterial community: highly degraded pasture, with 30 of N was applied broadcast, annually split along the rainy period (May to August). The N source was urea and P and K were not applied.…”

“…The association between diazotrophic bacteria and forage grasses can be able to overcome part of this limitation to plant development [30]. However, natural and anthropic imbalances can influence the bacterial community, interfering with its biochemical activity [31] and genetic diversity [27].…”