ارزیابی فعالیت آنزیم های خارج سلولی جدایه های Fusarium solani و بیماریزایی آن ها در لوبیا

Soilborne fungi are destructive pathogens on bean plants and can affect quality as well as yield of the plant. Fusarium rot, caused by Fusarium solani f. sp. phaseoli is one of the most prevalent soilborne bean diseases worldwide, and this fungus is of considerable importance due to the secretion of a large level of extracellular enzymes with wide applications in industry and agriculture. Destructive extracellular enzymes secreted by F. solani play an important role in the infection of plant tissues. In this study, the activity levels of cellulase, pectinase, lipase, and xylanase enzymes secreted by F. solani f. sp. phaseoli isolates UA22 and lk18 were investigated. Determining the activity of cellulase, pectinase, lipase, and xylanase enzymes was done via liquid culture media containing carboxymethyl cellulose, pectin, olive oil, and spelt-oat xylan, respectively. The vials were incubated on a shaker at 28±1 °C for 10 days, rotating at a speed of 110 revolutions per minute. Then, the activity levels of cellulase, pectinase, lipase, and xylanase enzymes secreted by the isolates were measured at wavelengths of 550, 540, 440, and 540 nm, respectively. Also, their pathogenicity was evaluated on the bean plants. Our findings revealed secretion of extracellular enzymes by the isolates UA22 and lk18. The highest levels of cellulase, pectinase, lipase, and xylanase enzyme activity in liquid culture media were obtained after 72, 144, 192, and 96 hours of cultivation, respectively. Based on these results, the secretion of extracellular enzymes and pathogenicity potential showed a positive correlation. Therefore, investigating the activity of extracellular enzymes in pathogens is a useful method for determining their pathogenicity potential.