Botrytis cinerea

Species of fungus

Botrytis cinerea, also known as gray mold, is a necrotrophic fungus that affects many plant species, although its most notable hosts are grapes, where it is known as "noble rot". This fungus is of significant economic importance in viticulture and horticulture due to its dual role as both a destructive pathogen and a beneficial agent in the production of certain wines.

Morphology

Botrytis conidiophore at 40X magnification

Botrytis cinerea is characterized by its grayish mycelium and the production of conidia on branched conidiophores. The conidia are typically ellipsoid and produced in clusters, giving the fungus its "bunch of grapes" appearance under the microscope. The fungus can also produce sclerotia, which are hardened masses of mycelium that allow it to survive in adverse conditions.

Life Cycle

The life cycle of Botrytis cinerea involves both asexual and sexual reproduction. Asexually, it produces conidia that disperse through the air to infect new hosts. Under certain conditions, it can also undergo sexual reproduction, forming apothecia that release ascospores. These spores can initiate new infections, particularly in humid environments.

Pathogenicity

Botrytis cinerea is a highly adaptable pathogen that can infect a wide range of hosts. It typically enters plant tissues through wounds or natural openings and secretes enzymes that degrade plant cell walls, leading to tissue maceration and rot. This fungus is notorious for causing post-harvest losses in fruits and vegetables.

Botrytis cinerea culture on a plate

Economic Impact

In viticulture, Botrytis cinerea is both a bane and a boon. While it can devastate grape crops by causing gray mold, it is also responsible for the "noble rot" that is essential in the production of certain sweet wines, such as Sauternes and Tokaji. The fungus dehydrates the grapes, concentrating sugars and flavors, which results in wines with unique characteristics.

Control Measures

Controlling Botrytis cinerea involves a combination of cultural, chemical, and biological strategies. Cultural practices include improving air circulation and reducing humidity around plants. Chemical controls involve the use of fungicides, although resistance can develop. Biological control agents, such as antagonistic fungi and bacteria, are also being explored.

Botrytis rot on apple (Goudreinet)

Research and Developments

Recent research has focused on understanding the genetic and molecular basis of Botrytis cinerea pathogenicity. Studies on mycoviruses that infect Botrytis cinerea have shown potential in reducing its virulence, offering a novel approach to control.

Mycoviruses of Botrytis cinerea

Related Pages

• Viticulture
• Fungal plant pathogens
• Noble rot
• Sclerotiniaceae