Symbiotic Burkholderia Species Show Diverse Arrangements of nif/fix and nod Genes and Lack Typical High-Affinity Cytochrome cbb3 Oxidase Genes

• DOI: 10.1094/mpmi-05-16-0091-r
• Publication Date: 2016-06-06T16:08:13Z
• Authors: Sofie E. De Meyer; Leah Briscoe; Pilar Martínez-Hi...; Christina M. Agap...; Paulina Estrada d...; Rekha Seshadri; Wayne Reeve; George Weinstock; Graham O’Hara; John G. Howieson; Ann M. Hirsch
• Keywords: 570; 16S; Mimosa; 572; Gene Transfer, Horizontal; Burkholderia; Nitrogen; Plant Biology & Botany; Gene Transfer; 610; Plant Biology; Microbiology; Plant Root Nodulation; Horizontal; Electron Transport Complex IV; 03 medical and health sciences; Bacterial Proteins; Nitrogen Fixation; RNA, Ribosomal, 16S; Medicine and Health Sciences; Genetics; Symbiosis; Phylogeny; Ribosomal; Plant biology; 0303 health sciences; Genome; Cupriavidus; Bacterial; Botany; Life Sciences; Biological Sciences; QR1-502; QK1-989; RNA; Genome, Bacterial; Transcription Factors

Genome analysis of fourteen mimosoid and four papilionoid beta-rhizobia together with reference alpha-rhizobia for both nodulation (nod) nitrogen-fixing (nif/fix) genes has shown phylogenetic congruence between 16S rRNA/MLSA (combined rRNA gene sequencing multilocus sequence analysis) nif/fix genes, indicating a free-living diazotrophic ancestry the beta-rhizobia. However, deeper genomic revealed complex symbiosis acquisition history in that clearly separates nodulating groups. Mimosoid-nodulating have nod tightly clustered nodBCIJHASU operon, whereas papilionoid-nodulating Burkholderia nodUSDABC nodIJ although their arrangement is not canonical because are subdivided by insertion nif other genes. Furthermore, spp. contain duplications several The nifHDKEN fixABC very closely related to those found diazotrophs. In contrast, nifA highly divergent groups, but species more similar than Surprisingly, all Burkholderia, fixNOQP fixGHIS required cbb3 cytochrome oxidase production assembly missing. symbiotic Cupriavidus strains fixNOQPGHIS revealing divergence evolution two distinct electron transport chains nitrogen fixation within