Journal Article

STABILITY OF PLASMID PROFILES OF HIGHLY VIRULENT RACES OF XANTHOMONAS CAMPESTRISPV. MALVACEARUM DURING STORAGE AND SUBCULTURING

Narra, H.P., Jayaraman, J., Verma, J.P., Fox, R.T.V.

2004

Overview

Four races of Xanthomonas campestris pv. malvacearum (Xcm) viz. races 23, 27 and 32 (isolated from Gossypium hirsutum) and race 23b (from Gossypium barbadense) were studied. The plasmid profile of the natural isolates showed four plasmids in races 23 and 23b (ca. 60, 40, 23, 8.2 kb), five in race 27 (ca. 60, 40, 23, 8.2 and 3.7 kb) and six in race 32 (ca. 60, 40, 23, 8.2, 3.7 and 1.6 kb). Continuously sub-cultured laboratory isolates of the Xcm races resulted in the loss of all but two plasmids, ca. 60 and 40 kb in size. When the laboratory isolates were passed through cotton (Gossypium hirsutum), they regained certain plasmids so that four plasmids were found in race 23 and 23b (ca. 60, 40, 23 and 8.2 kb), five in race 27 (ca. 60, 40, 23, 8.2 and 3.7 kb) and six in race 32 (ca. 60, 40, 23, 8.2, 3.7 and 1.6 kb), which was more or less similar to the original isolates. The isolates recovered from cotton maintained their plasmid profile (except for minor changes in the miniplasmids) after storage for six months at -70°C in 50% glycerol. It is suggested that plasmid profiles among highly virulent races of Xcm are unstable during repeated sub-culturing at room temperature, resulting in rapid loss of some plasmids. However, when the cultures were sub-cultured and stored at -70°C the plasmid profile was fairly stable except for the miniplasmids (ca. 3.7 and 1.6 kb).

• Publisher: An International Journal of the Italian Phytopathological Society
• Subject: Agriculture / Cotton / Phytopathology / Plasmids / Short Communication / Storage stability / Virulence / Virulence factors / Xanthomonas / Xanthomonas campestris