Microcalorimetric measurement of Trichoderma spp. growth at different temperatures

The growth of six Trichoderma spp. warm-weather strains (WWS) and temperate-weather strains (TWS) was determined by microcalorimetry at different temperatures from 10 to 35 °C. The metabolic heat production (p) and the apparent activation energy (Ea) were calculated. Significant differences among the strains were noted between 20 and 30 °C. The optimal growth temperature was 30 °C for strains TC74, T359, T479, and Th and was 35 °C for TC74M and T397. The p values were from 18 to 28 mW g−1 dry weight of mycelium and 11–16 mW g−1 of dry weight of mycelium for the WWS and TWS, respectively. The highest and lowest Ea values were observed for T479 (98 kJ mol−1) and Th (34 kJ mol−1), respectively. For WWS, the p value at the highest growth was directly related to antibiosis, and the Ea values were directly correlated to sclerotium parasitism. Both p and Ea were inversely related to sclerotium parasitism and pathogen growth inhibition, respectively. By contrast, the p value for TWS at maximal growth was inversely related to antibiosis while the Ea was directly related. Microcalorimetry was used to detect minute differences in metabolism heat among the Trichoderma strains, providing a rapid and accurate way to yield reproducible data.