ABSTRACT
The yerba-mate (Ilex paraguariensis) has great socioeconomic importance on family farming in Southerm Brazil. One of the main yerba-mate disease is root rotting, caused by Fusarium spp. Little is known about the pathogen physiology, especially regarding the aggressiveness associated with the production of extracellular enzymes. On this work, the aggressiveness of isolates of F. oxysporum and F. solani pathogenic to yerba-mate was evaluated and it was determined the activities of extracellular enzymes catalase, laccase, cellulase, caseinase, amylase, protease, lipase and pectinases produced by Fusarium spp. in culture medium. Six isolates of F. solani and one isolate of F. oxysporum pathogenic to yerba-mate were used. The F. oxysporum isolate proved to be less aggressive in relation to the other F. solani isolates. All isolates of Fusarium spp. produced, on a semiquantitative manner, the extracellular enzymes catalase, laccase, cellulase, caseinase, amylase, protease, lipase and pectinases (polygalacturonase and pectate lyase). However, the quantity produced for each enzyme was significantly different among the isolates. With the exception of the laccase and polygalacturonase enzymes, the M7C1 isolate showed the highest enzymatic index and was also responsible for the highest percentage of yerba-mate seedlings death.
Keywords
exoenzymes; root rotting; fungus