Utilization and synthesis of oligosaccharides by some pathogenic isolates of Colletotrichum capsici (Syd.) butler and bisby

Abstract

Utilization of four oligosaccharides (viz., maltose, sucrose, lactose and raffinose) as well as of the mixture of their hydrolytic products (viz., glucose, ½ glucose + ½ fructose, ½ glucose + ½ galactose and 1/3 glucose + 1/3 fructose + 1/3 galactose) by three isolates of Colletotrichum capsici (Syd.) Butler and Bisby obtained from leaf-spots of Codiaeum variegatum Blume, Manihot esculenta Crantz and Solanum melongena L. was studied chromatographically. Sucrose, maltose and raffinose were consumed through a hydrolytic pathway, while none of the hydrolytic product could be detected in the medium containing lactose. The pathogens were also capable of utilizing the hydrolytic products of the oligosaccharides. All of them had synthesized an oligosaccharide during the utilization of sucrose and maltose. They failed to do so during the assimilation of lactose. Only Manihot isolate of C. capsici synthesized an oligosaccharide, when it was allowed to grow on raffinose. The growth of all the isolates was better on sucrose than on glucose-fructose mixture. They also exhibited better growth on a mixture of glucose and galactose than on lactose. The growth of all of them was inferior on maltose than on glucose. Codiaeum and Solanum isolates of C. capsici grew better on raffinose than on a mixture of glucose, fructose and galactose. Manihot isolate of the same species, however, showed more or less identical growth on raffinose as well as on the mixture of its hydrolytic products.