Characterization of a new member of the Fusarium solani species complex causing peanut brown root rot.

CASASNOVAS, F.; REYNOSO M.M.; PALACIOS, S; MEZA, L; RAMIREZ, M.L.; CHULZE, S,N,; TORRES, A.M.

Rio de Janeiro, Brasil

Congreso; XLII Congreso Brasilero de Fitopatologia; 2009

Sociedad de Fitopatologia Brasileira

Peanut is an important crop in Argentina, with a production reaching 300,000 tons during 2007/2008 harvest season. Peanut brown root rot (PBRR) was first described in Argentina in 1992, and the disease has been important in seasons with long drought-stress periods with high incidence in some fields, producing significant economical losses. The etiological agent was first reported as Fusarium solani (Mart.) Appel. and Wollenw. Sny. and Hans, but the pathogen has not yet been well described. Our objective was to characterize morphological, physiological and genetically the etiological agents of PBRR. Strains isolated from symptomatic peanut plants showing brown root rot were evaluated. The physiological studies indicated that the etiological agent of PBRR could survive and grow effectively in soil and crop debris where matric stress is the major component of total water stress. Morphologically no differences were found between this pathogen and other species belonging to Fusarium solani species complex. AFLP analysis and phylogenetic analysis based on ITS region, a portion of translation elongation factor 1-á gene and, a portion of â-tubulin gene, showed that the pathogen could be a new formae specialis among the Fusarium solani species complex. The molecular tools used to characterize the pathogen allowed develop single-step PCR specific primers that reliably discriminate Fusarium solani causing PBRR.