Novel, non-symbiotic isolates of Neorhizobium from a dryland agricultural soil

PeerJ

article

Amalia Soenens¹  Juan Imperial¹ 

[1] Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria;Instituto de Ciencias Agrarias

关键词: Non-symbiotic;    Direct isolation;    rpoB;    16S rDNA;    nifH;    nodC;    repABC;    Phylogeny;    Genome sequencing;    Neorhizobium;   

DOI  :  10.7717/peerj.4776

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

Semi-selective enrichment, followed by PCR screening, resulted in the successful direct isolation of fast-growing Rhizobia from a dryland agricultural soil. Over 50% of these isolates belong to the genus Neorhizobium, as concluded from partial rpoB and near-complete 16S rDNA sequence analysis. Further genotypic and genomic analysis of five representative isolates confirmed that they form a coherent group within Neorhizobium, closer to N. galegae than to the remaining Neorhizobium species, but clearly differentiated from the former, and constituting at least one new genomospecies within Neorhizobium. All the isolates lacked nod and nif symbiotic genes but contained a repABC replication/maintenance region, characteristic of rhizobial plasmids, within large contigs from their draft genome sequences. These repABC sequences were related, but not identical, to repABC sequences found in symbiotic plasmids from N. galegae, suggesting that the non-symbiotic isolates have the potential to harbor symbiotic plasmids. This is the first report of non-symbiotic members of Neorhizobium from soil.

【 授权许可】

CC BY