Rhizobium ecuadorense sp. nov., an indigenous N2-fixing symbiont of the Ecuadorian common bean (Phaseolus vulgaris L.) genetic pool

Abstract

Rhizobium ecuadorense sp. nov., an indigenous N 2 -fixing symbiont of the Ecuadorian common bean (Phaseolus vulgaris L.) genetic pool

Genetic and phenotypic diversity of Rhizobium isolates from Southern Ecuador

“…Although few studies have reported on the genetic diversity of Rhizobium in Ecuador (Ribeiro et al, 2013), this is the first report of species diversity in the southern region of the country. Similar to this study, R. etli, R. leguminosarum and R. tropici have been previously isolated from common bean nodules (Martínez-Romero, 2003;Aguilar;Riva;Peltzer, 2004;Oliveira et al, 2011) and are considered to be the predominant occupant species of bean nodules in the Andean region (Junier et al, 2014;Ribeiro et al, 2015). Ecuador, north of Peru, Colombia and the Andean Region are currently considered to be the centers of domestication/diversity of the common bean (Oliveira et al, 2011).…”

“…The analysis of natural bean populations has led to the proposal of two major centers of diversification: the Mesoamerican center (Mexico, Central America and Colombia) and the Andean center (Ecuador, Peru and Bolivia) (Beebe et al, 2001;Junier et al, 2014). However, the genetic diversity of rhizobianodulating beans in Ecuador is, for the most part, unknown (Ribeiro et al, 2015). In previous studies, Bernal and Graham (2001) and Ribeiro et al (2013) reported on the diazotrophic rhizobial communities in soils of northern and central Ecuador.…”

“…Recently, a new species, Rhizobium ecuadorense sp. nov., which was obtained from a common bean nodule, has been described as a lineage from Ecuador (Ribeiro et al, 2015). This suggests that Ecuador is the center of genetic diversification for the common bean (Debouck et al, 1993), and symbionts of the several species of Rhizobium should be isolated from this region (Ribeiro et al, 2013).…”

“…In Ecuador, an Andean region from which common bean originates (Rodiño et al, 2010), few rhizobia identification studies have been conducted, despite potentially being an important source of rhizobial diversity, which is a key determinant of common bean productivity (Baginsky et al, 2015). Recently, Ribeiro et al (2015) determined the taxonomic affiliations of isolated strains from Ecuadorian soil previously reported by Bernal and Graham (2001) and Mexican strains, showing that all the Ecuadorian isolates corresponded to three novel lineages from the Rhizobium etli group that fall into the R. phaseoli/R. etli/R.…”

La diversidad de rizobios nativos de México a la luz de la genómica

“…Posteriormente, se ha identificado una diversidad amplia de linajes de rizobios de los nódulos de Phaseolus vulgaris con análisis tanto moleculares (Miranda-Sánchez et al, 2016;Ribeiro et al 2013;Wang et al, 2011) como genómicos en distintas regiones de México, del Caribe (Carrascal et al, 2016;Díaz-Alcántara et al, 2014;Santamaría et al, 2017;Tong et al, 2018) y de China, donde el frijol fue introducido y es cultivado a gran escala (Cao et al, 2014). Se han reclasificado a algunas cepas previamente consideradas como R. etli en otras especies cercanas, R. phaseoli (Ramírez-Bahena et al, 2008), R. ecuadorense (Ribeiro et al, 2015) y R. esperanzae (Cordeiro et al, 2017), mientras otros linajes nuevos no han sido todavía nombrados como nuevas especies (López-Guerrero et al, 2012). Es notable que distintas especies de rizobios con capacidad de formar nódulos en P. vulgaris comparten un plásmido simbiótico conservado que representa al simbiovar phaseoli o tropici, lo que indica que los plásmidos pueden transferirse entre rizobios en condiciones naturales (Cao et al, 2014), y se ha confirmado en experimentos de laboratorio (Brom et al, 1988;Martínez et al, 1987;Rogel et al, 2001).…”