Cellular fatty acid comparison of strains of Corynebacterium michiganense subsp. sepedonicum from potato and sugar beet

Abstract

The cellular fatty acid composition of Corynebacterium michiganense subsp. sepedonicum strains recovered from potato and sugar beet hosts were determined using gas-liquid chromatography. Fatty acid profiles were compared to profiles from other plant pathogenic coryneform bacteria. The most prevalent fatty acids present in C. michiganense subsp. sepedonicum were 12-methyl-tetradecanoic acid (a15:0), 14-methyl-hexadecanoic acid (a17:0), 14-methyl-pentadecanoic acid (i16:0), 12-methyl-4-tetradecenoic acid (a15:1), hexadecanoic acid (16:0), cis-9-octadecenoic acid (18:1c), and cis-9,12-octadecadienoic acid (18:2). In addition, some strains contained smaller amounts of 14, 15, 16, 17, 18, and 19 carbon fatty acids. All strains of plant pathogenic coryneform bacteria tested could be differentiated on the basis of either total fatty acid content (qualitative) or by ratios of cellular fatty acids (relative quantitative differences), e.g., a15:0/i16:0, a17:0/i16:0, a15:0/a17:0, i16:0/a15:1, a15:1/16:0, and 16:0/18:1. Strains of C. michiganense subsp. sepedonicum from sugar beet and potato were qualitatively and quantitatively very similar. On the basis of these results, it was clear that the endophytic strains of C.m. subsp. sepedonicum recovered from healthy sugar beets were indistinguishable from pathogenic strains recovered from potato. The bacteria from the two hosts should be considered as members of the same subspecies.