Presentation on theme: "Teleomorph vs Anamorph"— Presentation transcript:
1Teleomorph vs Anamorph The teleomorph (perfect stage) is the sexual stageThe anamorph (imperfect stage) is the asexual stageNectria - peritheciaFusarium - conidia** Images and lecture material were not entirely created by J. Bond.Some of this material was created by others.**
2Remember: most microbes are not pathogens on most plants! How pathogens attack plantsApple scabSouthern leaf rust of cornRemember: most microbes are not pathogens on most plants!
3Infection ProcessPathogens must gain access into plants to cause diseaseViruses – WoundsBacteria – Wounds, natural openingsFungi and Fungal Like Organisms – Wounds, natural openings, and direct penetrationNematodes – direct penetration
4Pathogens use plants for food, but most of the “food” is inside the cell. To get to this food, pathogens must first penetrate the cell wall.To penetrate the cell wall, pathogens must first get past the plant cuticle (usually).
5Regular cell wall2 layers: cellulose, pectin, hemicelluloses, ligninTough to get throughEpidermal cell wall2 layers plus cutin and wax covering.VERY tough to get through
6Mechanical forceOnly fungi, nematodes, and parasitic plants use mechanical force to get into the cellMost use force to get through wax layer (although they must adhere to the wax during penetration)Adherence is usually by appressoria
7Appressoria can exert tremendous pressure! Melanin strengthens fungal cell wall in appressoria and appears to be an important pathogenicity factorAppressoria also secrete cutinases, cellulases, pectinases- Once past the cuticle, fungus must continue to secrete cellulases, pectinases,proteinases to enter each and every cell.
8Utilization of the protoplast The protoplast contains the “food” that most pathogens are afterBut this food must first be degraded, then absorbedDegradation by enzymes - amylases, lipases, phospholipases, proteinases