PLP 150C1 1st Edition Lecture 17 Outline of Last Lecture I. PrototaxitesII. Disease due to fungiA. HistoplasmosisB. BlastomycosisC. CoccidioidomycosisIII. Skin infectionsA. CandidaB. Subcutaneous & invasive mycosesOutline of Current Lecture I. Fungi-invertebrate associationsA. Direct & indirect interactionsII. Nematode-trapping fungiIII. Endosymbionts of nematodesIV. ArthropodsCurrent LectureFungi-invertebrate associations - mostly predatory associations• Invertebrate trapping fungi, first discovered by Drechsler in 1933, who first observed fungi attacking nematodes (non-segmented round worms).• Most of the nematode-trapping fungi are ascomycetes & zygomycetes.• Scientists have tried to develop nematode-trapping fungi as a biological control alternative forplant-parasitic nematodes.• Some of the interactions are indirect - interfering with nematode survival◦ Fungi kill with mycotoxins◦ Destroy feeding sites of nematodes◦ Compete for food to reduce nematode multiplication◦ Mycorrhizal fungi improve the health of nematode-infected plants & may also restrict nematode development• Some are direct - which involved nematodes parasitizing them◦ Fungi use their trapping structure to actually trap them◦ Facultative parasitic fungi -> attack sedentary stages of nematode◦ Endoparasitic fungi -> obligate parasitesNematode-trapping fungi have several groups depending on their structure• Adhesive 3D networks• Adhesive columnar branches• Adhesive knobs• Constrictions and non-constricting structuresEndosymbionts of nematodes• The chytrid fungus Caternaria• No hyphal structures• The fungal evacuation tubes are outside the nematodeParasitic and pathogenic fungi of arthropods• Terrestrial & aquatic ecosystems• 750 species are pathogenic to insects• Some are used as biological control alternatives• Fungal symbionts of insects are quite diverse, but share some common traits:◦ Chitin◦ High reproductive rate◦ Important role in recycling organic
View Full Document
Unlocking...