Isolation and phenotypic characterization of rhizobia that nodulate cowpea in the Cerrado in Tocantins State, Brazil

Abstract

Depending on the nutritional characteristics and hardiness, the cowpea has become an important source of protein in North and Northeast regions of Brazil. The cowpea benefits from biological nitrogen fixation (BNF) and may receive part of the nitrogen needed for culture via symbiosis, which reduces production costs. Aiming to contribute to the optimization of the BNF in the culture of cowpea (Vigna unguiculata (L) Walp) in the cerrado of Tocantins, through the effectiveness of populations and diversity of rhizobia obtained in seven areas with and without crops , phenotypic isolation and characterization were performed (pH, time of growth characteristics of the colonies and mucus). We obtained 72 rhizobia and evaluated in a dendrogram showed a great diversity, with the formation of 18 groups and the five large groups with 70% similarity. The study of morphological and physiological characteristics reveals a fairly wide diversity of rhizobia and is usually related to studies at the DNA level.

Nodulation potential and phenotypic diversity of rhizobia nodulating cowpea isolated from major growing areas of Ethiopia

“…This indicates the nonspecific nodulation of cowpea by rhizobial species. Different studies have already expounded that both groups of rhizobia—fast and slow growing—can induce nodules on cowpea (Chagas et al., 2013; Martins et al., 1997; Mpepereki et al., 1996; Ondieki et al., 2017). Degefu et al.…”

“…Chagas et al. (2013) reported the formation of two clusters and five more subclusters by cowpea rhizobial isolates and suggested the wide diversity of native rhizobial isolates. Hence, the formation of six subclusters in this study indicates rhizobia nodulating cowpea are phenotypically diversified.…”

“…(1989) to characterize the rhizobial population in different ecosystems. These evaluation methods have the advantage of being fast, allowing a preliminary analysis of diversity and providing important information for their identification and grouping (Chagas et al., 2013).…”

“…comprising a large number of slow‐growing strains. This has led to a fallacy about their diversity as reports revealed the existence of both slow‐ and fast‐growing rhizobial isolates in the root nodule of cowpea (Chagas et al., 2013; Kenasa et al., 2018; Mpepereki et al., 1996; Ondieki et al., 2017). Notwithstanding, the diversity and biogeographic distribution of rhizobial symbionts nodulating cowpea in sub‐Saharan Africa are not well understood, although it is necessary for improved crop production (Chidebe et al., 2018).…”

Eco-physiological and physiological characterization of cowpea nodulating native rhizobia isolated from major production areas of Ethiopia

“…Chen et al (2005) reported that the study of rhizobia uses molecular techniques in investigating novel groups of rhizobia capable of nodulation and nitrogen fixation in different legume crops. However, Chagas Junior et al (2013) stated that the eco-physiological and physiological characterization of rhizobia has also been used to study and identify novel groups of rhizobia.…”