HPLC analysis for secondary metabolites detection in Sclerotium rolfsii isolated from chickpea

Chickpea (Cicer arietinum L.) is an economically important leguminous crop grown in Rabi season in barani areas of Pakistan. Among the biotic stresses responsible for its low production during last few decades, collar rot caused by fungus Sclerotium rolfsii Sacc., has caused serious economical losses to chickpea crop. The aim of the present research was to identify secondary metabolites among 12 isolates of S. rolfsii through HPLC analysis. The HPLC analysis of sclerotial filtrates revealed 4-17 peaks. Out of these, six were identified on the basis of their retention time (Rt) as gallic (Rt 2.86 min), oxalic (Rt 3.03 min), ferulic (Rt 3.30 min), indole-3 acetic (Rt 3.60 min), chlorogenic (Rt 4.16 min) and cinnamic (Rt 4.46 min) acids. Ferulic acid was identified in 9 isolates, IAA in 10 isolates, cinnamic acid in 11 isolates and chlorogenic acid in 5 isolates. Gallic and oxalic acids were found in all the isolates. Highest concentration in sclerotial filtrate of all isolates was gallic acid varying from 1.871-25.13mug/ml. Present study revealed that AM-04, AM-05, AM-09, AM-10 and AM-11 yielded severe collar rot infection in chickpea due to their ability to synthesize phenolic acids which act as a tool for their rigorous attack. AM-02 is less virulent strain which synthesized least number of phenolics and thus promotes mild infection against chickpea. So this information is helpful for plant breeders for the production of resistant varieties of chickpea against identified phenolic acids to inhibit or cease the infection caused by strains AM-04, AM-05, AM-09, AM-10 and AM-11 and thus reduce the economical losses to chickpea.