Brazilian-adapted soybean Bradyrhizobium strains uncover IS elements with potential impact on biological nitrogen fixation. Issue 11 (12th March 2019)

• Record Type: Journal Article
• Authors: Barros-Carvalho, Gesiele Almeida; Hungria, Mariangela; Lopes, Fabrício Martins; Van Sluys, Marie-Anne
• Is Part Of: FEMS microbiology letters. Volume 366:Issue 11(2019)
• Publication Date: 2019-03-12
• Subjects: bioinformatics -- N-fixing bacteria -- symbiotic genomic island -- transposable elements; Microbiology -- Periodicals; 579
• DOI: 10.1093/femsle/fnz046
• Languages: English
• ISSNs: 0378-1097

Abstract

ABSTRACT: Bradyrhizobium diazoefficiens CPAC 7 and Bradyrhizobium japonicum CPAC 15 are broadly used in commercial inoculants in Brazil, contributing to most of the nitrogen required by the soybean crop. These strains differ in their symbiotic properties: CPAC 7 is more efficient in fixing nitrogen, whereas CPAC 15 is more competitive. Comparative genomics revealed many transposases close to genes associated with symbiosis in the symbiotic island of these strains. Given the importance that insertion sequences (IS) elements have to bacterial genomes, we focused on identifying the local impact of these elements in the genomes of these and other related Bradyrhizobium strains to further understand their phenotypic differences. Analyses were performed using bioinformatics approaches. We found IS elements disrupting and inserted at regulatory regions of genes involved in symbiosis. Further comparative analyses with 21 Bradyrhizobium genomes revealed insertional polymorphism with distinguishing patterns between B. diazoefficiens and B. japonicum lineages. Finally, 13 of these potentially impacted genes are differentially expressed under symbiotic conditions in B. diazoefficiens USDA 110. Thus, IS elements are associated with the diversity of Bradyrhizobium, possibly by providing mechanisms for natural variation of symbiotic effectiveness. Abstract : The contribution of insertion sequences to the diversity of soybean-nodulating Bradyrhizobium strains in Brazil.