High-quality draft genome sequence of Ensifer meliloti Mlalz-1, a microsymbiont of Medicago laciniata (L.) miller collected in Lanzarote, Canary Islands, Spain

Abstract

Ensifer melilotiMlalz-1 (INSDC = ATZD00000000 ) is an aerobic, motile, Gram-negative, non-spore-forming rod that was isolated from an effective nitrogen-fixing nodule of Medicago laciniata(L.) Miller from a soil sample collected near the town of Guatiza on the island of Lanzarote, the Canary Islands, Spain. This strain nodulates and forms an effective symbiosis with the highly specific host M. laciniata. This rhizobial genome was sequenced as part of the DOE Joint Genome Institute 2010 Genomic Encyclopedia for Bacteria and Archaea-Root Nodule Bacteria (GEBA-RNB) sequencing project. Here the features of E. melilotiMlalz-1 are described, together with high-quality permanent draft genome sequence information and annotation. The 6,664,116 bp high-quality draft genome is arranged in 99 scaffolds of 100 contigs, containing 6314 protein-coding genes and 74 RNA-only encoding genes. Strain Mlalz-1 is closely related to Ensifer melilotiIAM 12611 T, Ensifer medicaeA 321T and Ensifer numidicusORS 1407 T, based on 16S rRNA gene sequences. gANI values of ≥98.1% support the classification of strain Mlalz-1 as E. meliloti. Nodulation of M. laciniata requires a specific nodC allele, and the nodC gene of strain Mlalz-1 shares ≥98% sequence identity with nodC of M. laciniata-nodulating Ensiferstrains, but ≤93% with nodC of Ensiferstrains that nodulate other Medicagospecies. Strain Mlalz-1 is unique among sequenced E. melilotistrains in possessing genes encoding components of a T2SS and in having two versions of the adaptive acid tolerance response lpiA-acvB operon. In E. medicaestrain WSM419 , lpiA is essential for enhancing survival in lethal acid conditions. The second copy of the lpiA-acvB operon of strain Mlalz-1 has highest sequence identity (> 96%) with that of E. medicaestrains, which suggests genetic recombination between strain Mlalz-1 and E. medicaeand the horizontal gene transfer of lpiA-acvB.