Suppression of damping-off disease causative agents using cellulase enzyme extracts of locally isolated cellulolytic fungi and their co-cultures

Abstract

Damping-off disease is caused by Pythium sp., Phytophthora sp., Rhizoctonia sp., and Fusarium sp., and affects seedlings at the nursery stage. Phytophthora and Pythium cell walls contain cellulose. The current study aimed to determine potential use of cellulase extracts of selected fungal species i.e. Talaromyces sp., Trichoderma sp., Aspergillus sp., A. niger, and Penicillium oxallicum to suppress these pathogens and to investigate the potential use of fungal co-culture extracts with the highest cellulase activity for seed treatment to control damping-off. The impact of cellulase extracts on pathogen growth was determined by agar well diffusion method. For seed treatment, tomato seeds were soaked in cellulase extracts from the selected co-culture for 24 h and were sown in pathogens inoculated soil samples. Cellulase extracts of Trichoderma and Aspergillus suppressed Phytophthora growth with 63% and 57% of inhibition percentages respectively. When seeds were treated with Talaromyces sp.+Aspergillus sp.+P. oxallicum co-culture extracts, the highest seedling emergence percentage was observed in Phytophthora sp. Fusarium sp., and four-pathogen mixture-inoculated soils respectively. Lowest disease incidence was observed in Phytophthora sp. inoculated soil. Results show the potential of cellulolytic fungal species; Trichoderma sp., Aspergillus sp., and co-culture of Talaromyces sp.+Aspergillus sp.+P. oxallicum in suppression of Phytophthora sp. a common causative agent of damping-off.

Keywords

• anti-pathogenic fungi, cellulolytic fungi, damping-off, phytophthora, seed treatment agents