Studies on Lyophilization and Other Preservation Methods for Native Trichoderma Isolates

Abstract

Trichoderma spp., are free-living fungi that are common in soil and root ecosystems. Trichoderma strains have long been recognized as biological agents, for the control of plant disease and for their ability to increase root growth and development, crop productivity, resistance to a biotic stresses, and uptake and use of nutrients. Colony characters, growth rate in culture, pigmentation arrangement of conidiophores and shape of conidia are the important characters used to distinguish different species of Trichoderma. The objective of the present study was to preserve native Trichoderma isolates for long time using lyophilization and other preservation methods such as silica gel, soil and charcoal. According to the Studies, best survival of spores was obtained in Silica gel (with 15% and 10% skim milk, at 88% and 85% respectively). Lyophilization with the following treatments produced optimal results (SDA + 3% glycerol, at 87%), (Skim milk 12% +Trehalose 7% + Na glutamate 1.5%, at 84%), (12% Skim milk+ ?%Trehalose, at 80%) and (12% Skim milk+ 10% sucrose, at 78%). These results varied from 78-88% viability level and hence these treatments may be considered to be of equivalent value. Soil or soil + sand mixture (2: 1) both showed near about similar viability but was lower at 30-33% as compared to other treatments. Spores were preserved in charcoal were viability was observed to be lowest among all treatments at 23%. Characterization of native strains of Trichoderma could be done particularly by morphological, physiological, Bioassay and molecular methods using sequence of internal transcribed spacer region of the rDNA. Out of 10 soil samples from sugarcane field being screened, a total 7 strains were isolated. These 7 strains (nruped as RT2014-01 to RT2014-07) showed different morphology and growth kinetics features