Pathogenicity and Sclerotial Development of Sclerotinia sclerotiorum: Involvement of Oxalic Acid and Chitin Synthesis

Sclerotinia sclerotiorum (Lib.) de Bary is among the world's most successful and omnivorous fungal plant pathogens. Included in the nearly 400 species of plants reported as hosts to this fungus are canola, alfalfa, soybean, sunflower, dry bean and potato. The general inability to develop resistant germplasm with these economically important crops to this pathogen has focused attention on the need for a more detailed examination of the pathogenic determinants involved in disease development. A mechanistic understanding of the successful strategy(ies) used by S. sclerotiorum in colonizing host plants and their linkage to fungal development may provide targets and/or novel approaches with which to design resistant crop plants. This proposal involved experiments which were successful in generating genetically-engineered plants harboring resistance to S. sclerotiorum, the establishment and improvement of molecular tools for the study of this pathogen and the analysis of the linkage between pathogenicity, sclerotial morphogenesis and two biosynthetic pathways: oxalic acid production and chitin synthesis. The highly collaborative project has improved our understanding of S. sclerotiorum pathogenicity, established reliable molecular techniques to facilitate experimental manipilation and generated transgenic plants which are resistant to this econimically important fungus.