Abstract:

【Objective】 Screening isolates from plant pathogenic fungi which be able to produce laccase and determining the laccase activity could give a deep insight into functional research for the pathogenicity of laccase. 【Method】 Using 2,2’-azino-bis[3-ethylbenzthiazoline-6-sulfonic acid] (ABTS) as substrate, isolates with laccase were screened from plant pathogenic fungi through the plate-color reaction and confirmed that these isolates had a role in lignin degradation using aniline blue (Azure-B). Laccase activity of six different isolates was compared using spectrophotometer at 420 nm. The effect of pathogenicity from laccase was analyzed using the histopathology. 【Result】 Ten isolates with a role in lignin degradation were screened from twenty plant pathogenic fungi. Setosphaeria turcica and Pestalotiopsis microspora contained the highest intracellular and extracellular laccase activity, which were 18.984 and 0.919 U?mL-1, respectively. The analysis of histopathology in S. turcica showed that maize leaves were oxidated by laccase which could accelerate the extention of pathogen against the host. 【Conclusion】 Most of the laccase in the plant pathogenic fungi were intracellular laccase which had a role in lignin degradation. In this study, laccase of S. turcica was found that could contribute to the expansion of pathogen in the host tissue.

Key words: fungi, laccase, enzyme activity, pathogenicity