ارزیابی میزان تولید آنزیم‌های خارج سلولی ترشح شده توسط جدایه‌های بومی Trichoderma harzianum

Different species of Trichoderma produce a large variety of secondary metabolites with various biological activities. The production of extracellular enzymes is one of the strategies used by this fungus in the biocontrol process. The use of Trichoderma fungus due to its compatibility with the environment and less stability can be recommended as an effective method in controlling pathogens and improving vigor and seed germination indices. Cumin bioprimed seeds with T. harzianum causing increase amount of protein and enzymatic antioxidants in seedlings. The aim of this study was to investigate the presence or absence of a relationship between the effect of the production rate of amylase, protease, cellulase, xylanase, chitinase and lipase enzymes produced by 10 native isolates of T. harzianum received from the collection of plant pathology laboratory at Ferdowsi University of Mashhad and the efficiency rate of cumin bioprimed seeds on improvement of vigor and germination indices. For extracting amylase, protease, cellulase, xylanase, chitinase and lipase enzymes produced by fungal isolates from liquid media containing starch, azocasein, carboxymethyl cellulose, oat xylan, chitin and olive oil were used, respectively. Vials were incubated at 25±1 °C on a rotating shaker with 120 revolutions per minute (rpm) for 10 days, the rate of amylase, protease, cellulase, xylanase, chitinase and lipase secreted by fungal isolates were evaluated at wavelengths of 550, 440, 550, 540, 544 and 440, respectively. The concentration of extracellular proteins produced of fungal isolates were measured using Bradford's method. The results of this study showed that all isolates of T. harzianum isolates produce extracellular enzymes as the main cell wall hydrolyzing enzymes. Analyzing of cell wall degrading enzymes (CWDEs) produced revealed that the maximum production rate of each enzyme was different for different isolates of T. harzianum. The maximum level of CWDEs produced were among T. harzianum isolates for amylase from 197.7 to 338 μg.ml-1, protease from 15.3 to 26.7 μg.ml-1, xylanase from 685 to 1238.7 μg.ml-1, cellulase from 442 to 723.3 μg.ml-1, chitinase from 12.7 to 20.7 μg.ml-1 and lipase from 40.3 to 22.7 μg.ml-1. The highest rate of extracellular protein and CWDEs production were observed in TH7 isolate. Also, the results of comparing the effect of cumin bioprimed seeds with T. harzianum isolates showed that TH7 isolate significantly affected the vigor and seed germination indices and improved the quality and health of seed and seedling. Findings of this study showed that the efficiency rate of cumin bioprimed seeds is affected by the production rate of extracellular enzymes secreted by native isolates of T. harzianum.