5 Ergot of rye Caused by Claviceps purpurea. Cause of ergotism: “Holy Fire” or “St. Anthony’s Fire”.Sclerotia are dangerous.Witch hunts.Caused low fertility and death in 14th-18th century Europe.
6 Other toxins made by fungi Endophytic fungi (Acremonium) in grasses can be toxic to cattle (fescue toxicosis)Other mycotoxins:OchratoxinsAflatoxins - carcinogenicFumonosins - blind stagger of horsesPatulin - bleeding in lungs and brain, kidney damage, cancer
7 Medicines that come from fungi Penicillin. Penicillium chrysogenum. Alexander Fleming, 1928.CephalosporinCyclosporin
8 Fungal diseases of humans - mycoses Trichophyton rubrum. Causal agent of athlete’s foot. Came from tropics.Candida albicans. Causes candidiasis = yeast infections.Around genitalia.Disease of mouth and throat.Blastomycosis, Cryptococcosis, Histoplasmosis, Aspergillosis are other diseases.
9 Smut infection of a wheat field in Eastern Washington (1956)
13 Examples of symptoms caused by fungi: CankersStorage rots of fruits and vegetablesRust, mildewsLeaf spots
14 Pathogen life stylesNecrotrophs - kill host cells with toxins and hydrolytic enzymes.Ex: Botrytis cinerea.Biotrophs - specialize on a living host.Ex. Powdery mildews and rusts.Hemibiotrophs - start out biotrophic. Then, they kill the host cells. Ex. Phytophthora infestans.
17 Characteristics of grey mold B. cinerea is a necrotroph, entering the plant through dead or dying tissue.It is a pathogen that attacks almost any known plant species. It invades healthy tissue through dead petals or leaves or dying wood.
18 Botrytis cinerea causes rots on fruits and vegetables, blossom blights, damping off, stem cankers, leaf spots and bulb rots.scleriotia
19 In the field, blossom blight often precede the fruit rots The fungus enters the fruit through the dead flower petals.
20 The fungus Botrytis cinerea Develops grey mycelium with long, branched conidiophores with clusters of one-celled, ovoid conidia.The conidiophores and conidia resemble a grapelike cluster.
22 Botrytis cinerea of tomato Spots on fruits are from spores that have landedAttack on fruit originated in the flower
23 Grey mould - continuedB. cinerea overwinters as mycelium in decaying plant debris or as sclerotia - black, hard resting structures.It also attacks fruit and vegetables during storage. The fruits rot internally (often from the flower end) and a soft mycelial mat develops on the surface. The fungus does most damage when it is very humid and damp.
25 Powdery mildew on roseSphaerotheca pannosa is the causal agent of powdery mildew on roses. It is an example of a biotroph: It grows only in living plant tissue.The white, powdery appearance is due to conidiophores/conidia
36 Incompatibility systems Fungi (ascomycetes) have mating types. They are designated MATa and MATa (yeast), MATA and MATa (Neurospora) or MAT1-1 and MAT1-2.Sexual reproduction in a heterothallic ascomycete requires the participation of different mating types. In a homothallic strain the fusing individuals are of the same mating type. The inability of two individuals of the same mating type to fuse is called vegetative incompatibility.