The radiation of nodulated Chamaecrista species from the rainforest into more diverse habitats has been accompanied by a reduction in growth form and a shift from fixation threads to symbiosomes.

All non-Mimosoid nodulated genera in the legume subfamily Caesalpinioideae confine their rhizobial symbionts within cell wall-bound 'fixation threads' (FTs). The exception is the large genus Chamaecrista in which shrubs and subshrubs house their rhizobial bacteroids more intimately within symbiosomes, whereas large trees have FTs. This study aimed to unravel the evolutionary relationships between Chamaecrista growth habit, habitat, nodule bacteroid type, and rhizobial genotype.

The large mimosoid genus Inga Mill. (tribe Ingeae, Caesalpinioideae) is nodulated by diverse Bradyrhizobium strains in its main centers of diversity in Brazil.

Inga (Caesalpinioideae) is the type genus of the Ingeae tribe in the mimosoid clade. It comprises about 300 species, all trees or treelets, and has an exclusively neotropical distribution, with Brazil as its main center of diversity. In this study, we analyzed the diversity of 40 strains of rhizobia isolated from root nodules collected from ten species of Inga belonging to different types of vegetation in Brazil.

Brazilian species of Calliandra Benth. (tribe Ingeae) are nodulated by diverse strains of Paraburkholderia.

The Chapada Diamantina in NE of Brazil is a biodiversity hotspot and a center of radiation for many Neotropical legume genera, such as Calliandra and Mimosa. The present study aimed to evaluate nodulation in Calliandra species endemic to various environments, and to characterize the diversity of their symbiotic rhizobia using housekeeping (16S rRNA, recA) and plasmid-borne, symbiosis-related (nifH and nodC) genes. The nodulation ability of selected isolates was assessed.

Diverse genotypes of Bradyrhizobium nodulate herbaceous Chamaecrista (Moench) (Fabaceae, Caesalpinioideae) species in Brazil.

The genus Chamaecrista comprises more than 330 species which are mainly distributed across tropical America, especially in Brazil (256 spp.), the main center of radiation. In this study, nodulation of herbaceous Chamaecrista species that are commonly found growing in different vegetation types in the north eastern Brazilian state of Bahia was assessed together with the diversity of rhizobia isolated from their root nodules.

Burkholderia species are the most common and preferred nodulating symbionts of the Piptadenia group (tribe Mimoseae).

Burkholderia legume symbionts (also called α-rhizobia) are ancient in origin and are the main nitrogen-fixing symbionts of species belonging to the large genus Mimosa in Brazil. We investigated the extent of the affinity between Burkholderia and species in the tribe Mimoseae by studying symbionts of the genera Piptadenia (P.), Parapiptadenia (Pp.