Pathogenicity and enzymatic activity of Fusarium graminearum isolated from wheat grains

ROJO RODRIGO; KIKOT GISELE; HOURS ROQUE; ALCONADA TERESA; GASONI LAURA

Mar del Plata

Congreso; VI Congreso Latinoamericano de Micología; 2008

Asociación Latinoamericana de Micología

The pectinase and protease activities are considered important factors of pathogenicity. The objetive of this research was to evaluate the severity of seedling symptoms in two wheat varieties (1 and 2), and to determine the levels of pectinases and proteinases produced by the pathogen. Seven isolates of F. graminearum were obtained from infected grains. The pathogenicity of the isolates was determined in two trials, with 10 seeds of each wheat variety per pot. Each pot contained infected substrate with each pathogen isolate. The disease severity was evaluated at 20 days after sowing. The enzymatic activities were measured with inducing liquid cultures, using polygalacturonic acid as substrate for the pectinase activity detection (Abs = 660 nm) and casein for the proteinase activity detection (Abs = 280 nm). Six isolates were pathogenic in seedlings. The disease symptoms were more conspicuous in the variety 1. All evaluated isolates showed moderate pectinase and proteinase activities since the first culture days. These preliminary results showed that isolates from infected grains can produce variable severity in seedlings depending of  the wheat variety used, and can produce extracellular enzymes that could be involved in the success of the pathogen establishment.