Nucleotide sequences, genetic organization, and distribution of pEU30 and pEL60 from Erwinia amylovora

Abstract

The nucleotide sequences, genetic organization, and distribution of plasmids pEU30 (30,314 bp) and pEL60 (60,145 bp) from the plant pathogen Erwinia amylovora are described. The newly characterized pEU30 and pEL60 plasmids inhabited strains isolated in the western United States and Lebanon, respectively. The gene content of pEU30 resembled plasmids found in plant-associated bacteria, while that of pEL60 was most similar to IncL/M plasmids inhabiting enteric bacteria.

FIG. 1.

Plasmid profiles of selected E. amylovora strains and pEA29-cured derivatives. Lane 1, Ea322; lane 2, CA11; lane 3, Ea88; lane 4, Ea88 cured of pEA29; lane 5, UTRJ2; lane 6, UTRJ2⁻ (cured of pEA29); lane 7, LebB66; lane 8, LebB66⁻ (cured of pEA29); lane 9, MR1; lane 10, water control.

FIG. 2.

Circular genetic maps of the 30,314-bp plasmid pEU30 (A) and 60,145-bp plasmid pEL60 (B) and their 25 and 68 identified ORFs, respectively. repA is designated orf1 in pEU30; tir is designated orf1 of pEL60 to closely match the gene order of the highly related plasmid pCTX-M3 from C. freundii (GenBank accession number NC_0044644). Genes are color coded on the basis of function as follows: replication and stability, blue; ecological fitness, yellow; transcriptional regulators, red; and conjugation- or plasmid-specific functions, green. The number or identity of each ORF is located inside the circle. On the pEL60 genetic map, the asterisks denote locations of 27 and 2.6-kb sequence insertions downstream of repA and pemK in the closely related plasmid pCTX-M3.