Utilization of nutritional compounds and sclerotial development of Sclerotium rolfsii isolated from Elaeis guineensis and Xanthosoma mafaffa in Ghana

Abstract

Sclerotium rolfsii is a facultative soil parasite of economic importance causing disease of several economic crop plants. Bacterial and fungal parasites are themselves an assemblage of strains differing genetically and liable to variation. The possible effect of external nutrients on different S. rolfsii strains in Ghana has not been studied. In this study the utilization of twelve different nutritional compounds and sclerotia formation by five strains of Sclerotium rolfsii, SrXLL, SrXA1, SrXA2, SrEL1 and SrEL2 was investigated. In broth media with different carbon compounds - fructose, glucose, maltose, starch and sucrose - and with different nitrogen compounds - ammonium chloride, Ammonium nitrate, Asparagine, Peptone and Sodium nitrate - a clearly discernible order of ability to utilize the two groups of compounds was noticed. The order of the strains in descending order of efficiency was SrEL2 > SrEL1 > SrXLL > SrXA1 > SrXA2. Among the carbon compounds the least utilized was starch. The best carbon compound varied with the the strains. Peptone was universally a good nitrogen source. over a concentration range of 0.5 to 2.0%, the greatest amount of pectolytic enzymes was produced in pectin media (20.0 per minute). Filtrates of strains SrXLL, SrXA1 and SrEL2 showed greater pectolytic enzymes activity than those of strains SrXA2 and SrEL1. But strains SrXA1 ans SrXA2 showed greater ability to break down cellulose than the other three strains. In all the media studied the pH of the culture filtrate decreased to acidic levels at the end of incubation period