Prospecting of efficient rhizobia for peanut inoculation in a Planosol under different vegetation covers

Abstract

Peanut (Arachis hypogaea L.) is capable of establishing an efficient symbiosis with a wide range of rhizobia, nevertheless, the inoculation of this legume is under used due to lack of information on the bacteria naturally established in soils and the agronomic and economic viabil ity of the practice. The aim of this study was to evaluate the diversity and the symbiotic efficiency of peanut rhizobia from a Planosol under different vegetation covers (native vegetation, sugarcane cultivation and fallow after sugarcane cultivation), located in Zona da Mata, Northeast of Brazil. A total of 177 isolates were obtained from peanut nodules, most of them having the characteristic of rapid growth and acidification of the Yeast Mannitol Agar (YMA) medium. The isolates obtained from soil sample s with native vegetation cover showed higher relative abundance, higher species richness and greater uniformity of morphological groups of rhizobia. Eighteen isolates were evaluated for their ability to nodulate peanuts, of which 13 have been authenticated and submitted to evaluation of symbiotic efficiency in pots with soil. The isolate 23M showed the best symbiotic performance in pots with soil. In the field, plants inoculated with the isolate 23M showed better performance than non-inoculated plants, in addition to a grain yield (kg ha -1 ) similar to that of plants inoculated with recommended bacteria or receiving 200 kg ha -1 N.

Can Bradyrhizobium strains inoculation reduce water deficit effects on peanuts?

“…Bradyrhizobium strains are the favorite micro-symbionts of peanut and large amounts of nitrogen can be fixed in trials under field conditions (Thies et al 1991;Valetti et al 2016). Within the Bradyrhizobium group, peanuts can nodulate with bacteria belonging to the B. elkanii clade, such as the commercial strain SEMIA 6144 or the clade B. japonicum, as several isolated strains from the semi-arid region of Brazil (Santos et al 2017a).…”

“…Comparison of the almost complete sequence (1268 nt) of the 16S rRNA gene of strain ESA 123 showed that this isolate is classified within the B. japonicum clade with the most similarity to the strain type 14-3 T B. kavangense. This species has recently been described, isolated from peanut nodules in Namibia (Grönemeyer et al 2015) and bacteria with sequences of the 16S rRNA gene related to B. kavangense were later isolated in South Africa (Jaiswal et al 2017) and in Brazil (Santos et al 2017a). Although the 16S rRNA gene sequence shows high similarity (98.97%) to B. kavangense, the ESA 123 strain may represent a new species, since the taxonomy of Bradyrhizobium is complex and cannot be elucidated only with the 16S rRNA allele (Hungria et al 2015).…”

“…Peanut is able to associate efficiently with different rhizobial strains (Melo et al 2016), presenting higher efficiency the Bradyrhizobium genus (Valetti et al 2016;Santos et al 2017a). During the last years, some studies have been carried out in Brazil aiming to evaluate the biodiversity (Lyra et al 2013;Torres-Júnior et al 2014;Santos et al 2017a), the symbiotic efficiency (Torres-Júnior et al 2014;Santos et al 2017a, b), and the agronomic efficiency of new rhizobium strains (Sizenando et al 2016). However, the potential of these bacteria to reduce the abiotic stresses, as water deficit, for example, has not been investigated.…”

“…The ESA 123 strain of Bradyrhizobium sp., native from a soil in the municipality of Barbalha (Ceará, Brazil), has already been indicated as a bacterium with high symbiotic efficiency (Santos et al 2017a) and agronomic efficiency in different sites of the Brazilian semi-arid region (Sizenando et al 2016). This strain may present certain drought tolerance since it is from a dry region and is efficient in fixing N in association with peanut.…”

Diversidade rizobiana em função de solo e clima no semiárido pernambucano

“…A diversidade microbiana é afetada pelas características climáticas como o aumento da temperatura atmosférica (MENDES et al, 2017) e por características edafoclimáticas (SILVA et al, 2017). Para esta pesquisa através dos registros climatológicos, percebe-se que Bom Jardim (1678mm e 28 °C) tem um regime de chuvas mais frequente, porém com temperaturas semelhantes às de Serra Talhada (686mm e 29 °C).…”