|The interesting case of soybean seedborne Fusarium spp.: from identity to pathogenicity.|
R. Pedrozo (1), J. J. Fenoglio (1), C. R. Little (1), R. PEDROZO (1). (1) Kansas State University, Manhattan, KS, U.S.A.
Although <i>Fusarium</i> spp. are among the most important pathogen groups on soybeans, their identity and importance as seedborne pathogens remain unclear. Thus, the objective of this work was to determine the identity of soybean seedborne <i>Fusarium</i> spp. and to study the potential of some species to impact seedling vigor and seed quality in pathogenicity assays. Seed was collected from 408 soybean samples produced in ten counties in the state of Kansas, USA during three growing seasons, 2010-2012. A semi-selective medium (PCNB) was used for fungal isolations and identification was based upon morphological characters and PCR. Isolate pathogenicity was assessed in the laboratory and greenhouse. The three-year screening effort showed that nine <i>Fusarium</i> species were seedborne. <i>F. semitectum </i>(FSE) was the most frequently encountered species (56.42%), followed by <i>F. proliferatum </i>(FPR; 19.25%), <i>F. verticillioides</i> (FVE; 13.20%),<i> F. acuminatum </i>(FAC; 2.85%)<i>, F. equiseti</i> (FEQ; 2.80%)<i>, F. thapsinum </i>(FTH; 2.22%), <i>F. fujikuroi</i> (FFU; 1.95%),<i> F. oxysporum </i>(FOX; 0.98%) and <i>F. graminearum</i> (FGR; 0.33%). Regarding their pathogenicity, only soybean seeds artificially infested with FPR, FGR, FTH, FFU and FOX reduced seed germination when compared with non-inoculated seeds (control) in both environments. Additional experiments are underway to further explore soybean seedborne <i>Fusarium</i> pathogenicity behavior and its potential implication on seed health testing.