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Poster: Biology & Disease Mgmt: Mycology


Improved plant-based culture media for growth and sporulation of Cercospora janseana
S. UPPALA (1), B. Liu (2), M. Wu (2), L. Zhou (3), X. Zhou (4) (1) Texas A & M AgriLife Research Center, U.S.A.; (2) Hunan Agricultural University, China; (3) Texas A&M AgriLife Research, U.S.A.; (4) Texas A&M AgriLife Research Center, U.S.A.

Cercospora janseana is the fungus causing narrow brown leaf spot, a disease that has increased its importance in recent years in the U. S. In vitro studies are essential to better understand the biology of this pathogen and to develop effective strategies for management of this disease. However, the fungus grows very slowly and produces sparse conidia in common agar media. An In vitro study was conducted to evaluate various plant-based agar media in comparison with common agar media for their effects on radial growth and sporulation of C. janseana. Included in this study were extracts of dried rice leaves, stems, straw, roots and hulls; fresh rice leaf extract, dried extracts of barnyard grass leaves and sorghum leaves, clarified V8, and potato dextrose agar. All plant-based agar media were tested at four concentrations (25, 50, 100 and 200 g/L). Petri plates with various media were plated with a disc of 1-week-old actively growing fungus at the center and incubated at 28 ÂșC with the 12:12 h (light:dark) cycle. Radial growth was measured at weekly intervals for 2 weeks and sporulation was measured at the end of 2 weeks. Radial growth and sporulation differed among various media and their concentrations. Among the various media tested, dried rice leaf extract, dried barnyard grass, fresh rice leaf extract and V8 media consistently supported highest radial growth of the fungus. V8 medium also supported the maximum production of conidia of this fungus.