Exploitation of saline tolerance in Trichoderma spp. and their potential in lytic enzyme production

Abstract

Biocontrol agents like Trichoderma spp. are vital in sustainable agriculture, offering eco-friendly alternatives to chemical pesticides. This study screened 35 Trichoderma isolates from five agro-ecological zones in Kerala for salt tolerance on PDA medium with NaCl concentrations ranging from 0.5 M to 2 M. With increase in concentration, the colony diameter of Trichoderma decreased. At 1 M NaCl, six isolates (ALT3, AMB1, EDC1, ERV2, ERV5, TDP1) showed no mycelial inhibition, while others exhibited 1.11% to 92.22% inhibition compared to control (without NaCl). Six isolates showed less than 50% mycelial inhibition at 1.5 M NaCl concentration, including NKL1 which displayed the lowest mycelial inhibition even at 2 M NaCl with 60% mycelial inhibition. Fifteen selected isolates from saline tolerance study were assessed for lytic enzyme production such as β-1,3-glucanase, protease and chitinase in culture media provided with enzyme substrates. β-1,3-glucanase activity ranged from 4.7 to 7.3 U/ml. Isolate PAT6 showed the highest protease activity (3.9 U/ml) and ERV4 the lowest (1.43 U/ml). All isolates produced chitinase, with activities ranging from 1.99 to 2.41 U/ml.