Genome sequence of Ensifer adhaerens OV14 provides insights into its ability as a novel vector for the genetic transformation of plant genomes

Abstract

Additional file 1:Figure S1. Circular representation of the four replicons of E. adhaerens OV14.

Figure S2. Synteny plots showing total sequence of Ensifer adhaerens OV14 pOV14 (top bar) vs Agrobacterium tumefaciens C58 pTi (bottom bar), computed using DoubleACT version2 on tBLASTx setting with cut off set at 100. Visualised in Artemis ACT.

Additional file 2; BLAST of Ensifer adhaerens OV14 replicons.xlsx. Excel file includes tables of BLAST search of individual Ensifer adhaerens OV14 replicons

Additional file 3. BLAST of Agrobacterium tumefaciens C58 replicons.xlsx. Excel file includes tables of BLAST searches of individual Agrobacterium tumefaciens C58

Background: Recently it has been shown that Ensifer adhaerens can be used as a plant transformation technology, transferring genes into several plant genomes when equipped with a Ti plasmid. For this study, we have sequenced the genome of Ensifer adhaerens OV14 (OV14) and compared it with those of Agrobacterium tumefaciens C58 (C58) and Sinorhizobium meliloti 1021 (1021); the latter of which has also demonstrated a capacity to genetically transform crop genomes, albeit at significantly reduced frequencies. Results: The 7.7 Mb OV14 genome comprises two chromosomes and two plasmids. All protein coding regions in the OV14 genome were functionally grouped based on an eggNOG database. No genes homologous to the A. tumefaciens Ti plasmid vir genes appeared to be present in the OV14 genome. Unexpectedly, OV14 and 1021 were found to possess homologs to chromosomal based genes cited as essential to A. tumefaciens T-DNA transfer. Of significance, genes that are non-essential but exert a positive influence on virulence and the ability to genetically transform host genomes were identified in OV14 but were absent from the 1021 genome. Conclusions: This study reveals the presence of homologs to chromosomally based Agrobacterium genes that support T-DNA transfer within the genome of OV14 and other alphaproteobacteria. The sequencing and analysis of the OV14 genome increases our understanding of T-DNA transfer by non-Agrobacterium species and creates a platform for the continued improvement of Ensifer-mediated transformation (EMT).