Microbes and Plant Diseases

Plants growing in  extremely dry soil and arid conditions that are under stress will be more prone to infection. Powdery mildew is a powdery fungus that grows mostly on the upper surface of leaves. It is usually white in colour. It will occasionally spread to the underside of leaves and other parts of the plant, such as stems and sometimes flowers and fruit. Powdery mildew prospers in dry soil conditions.

It is a result of Sclerotium rolfsii which is a soil-inhabiting fungus affecting the seed of the plant. This seed-borne disease infects the seed and it turns into blue and black patches.

Blossom end rot is a common problem of tomatoes, peppers and aubergines grown in a greenhouse caused by erratic watering or dryness at the root. Brown sunken spots develop at the bottom of the fruit opposite stem.

 Ampelomyces quisqualis is an anamorphic fungus that is a hyperparasite of powdery mildews. This parasitism reduces growth and may eventually kill the mildew. L. longisporum is used for management of aphid pests. Insects are infected when they come into contact with the sticky fungal spores which then grow and invade the body. Thus the internal organs are consumed.

Ringworm is a fungal infection caused by dermatophytes, despite its misleading name. Elephantiasis is caused by parasitic worms, Diphtheria by bacteria, and Pneumonia can be bacterial or viral - none are fungal diseases.

Spores are released when the sporangium wall ruptures or breaks open. This passive dispersal mechanism allows spores to be carried by wind to new locations for germination.

The study of fungi is called mycology.

The Enter-Doudoroff pathway is an alternative pathway of glucose metabolisms. It is found in aerobic and anaerobic prokaryotes (especially in Gram negative bacteria) but not found in eukaryotes.

Coprinus comatus is a common fungus often seen growing on lawns, along gravel roads and waste areas. The young fruit bodies first appear as white cylinders emerging from the ground, then the bell-shaped caps open out. The caps are white and covered with scales.

Oak wilt is a fungal disease that can quickly kill an oak tree. It is caused by the fungus Ceratocystis fagacearum. The fungus is spread from diseased to healthy trees by insect vectors or via connections between tree roots.

Gliotoxin is a sulfur-containing mycotoxin produced by several species of fungi, including pathogens of humans such as Aspergillus fumigatus.It possesses immunosuppressive properties as it may suppress and cause apoptosis in certain types of cells of the immune system, including neutrophils, eosinophils, granulocytes, macrophages, and thymocytes.

Mycotoxins can appear in the food chain as a result of fungal infection of crops, either by being eaten directly by humans or by being used as livestock feed. Mycotoxins greatly resist decomposition or being broken down in digestion, so they remain in the food chain in meat and dairy products.

Completoria is itself monotypic, containing a single species, Completoria complens. The species is rare, known only from greenhouse cultures where it grows as an obligate intracellular parasite of fern gametophytes.

Pine trees are susceptible to pine pitch canker. Pine pitch canker first kills the tips of branches, then spreads down entire branches, and ultimately it can kill the whole tree. Infected trees die because the fungus thrives inside the tree's vascular tissue and blocks its water supply. The fungus is spread through the beetles that attack the pine cones.