Growth of Albugo candida (race unidentified) on Brassica juncea callus cultures

Abstract

An obligate fungus Albugo candida (Pers. ex Lév.) Ktze. (race unidentified) was successfully grown on host callus tissues of Brassica juncea cv. Varuna. Of the various type of diseased explants used, young (green) hypertrophied inflorescence axis bearing non-erumpent zoosporangial blisters allowed the fungus to multiply asexually over the host calli on modified MS-medium (Murashige and Skoog, 1962). The dual cultures were maintained up to 6–8 subcultures without loss of viability of zoosporangia on MS-medium supplemented with 10.0 mg L⁻¹ IBA, 0.05 mg L⁻¹ kinetin, 25.0 mg L⁻¹ AA, 1.0 mg L⁻¹ biotin, 1.0 mg L⁻¹ thiamine-HCl and 1.0 g L⁻¹ casein hydrolysate. The fungus grew only on the callus cells and not axenically on the medium. Pathogenicity test and histopathology of cultures proved the existence of the viable fungus in vitro.