atroviride is a filamentous
cosmopolitan fungus, commonly found in soil, and isolated from both tropic
as well as temperate climates. It is best known for its biocontrol capabilities
against a range of phytopathogenic fungi including Rhizoctonia solani and Botrytis
cinerea, which are pests
of hundreds of plant crops, including tomatoes, beans, cucumber, strawberries,
cotton and grapes. The mechanisms of biocontrol have been studied in
two strains of
T. atroviride P1, (ATCC 74058) --a fungicide resistant mutant
of an isolate from the UK-- and the wild-type isolate IMI 206040, from Sweden. These studies include the formation and characterization
of various chitinases, beta-glucanases and proteases, regulation
of their transcription and identification of some of the cis- and trans-acting
factors; the formation of antibiotics, particularly 6-pentyl-alpha-pyrone and peptaibols; and the involvement of signal transductory cascades
(G-proteins and MAP-kinases) in the above processes. In addition, T.
atroviride has become a model system for blue-light induced conidiation
and gene expression, as well as characterization of the blue light receptors,
and the mechanism by which it can solubilize coal (involvement of laccases)
has been investigated in some detail.
Trichoderma atroviride (red) growing along the hyphae of a host fungus
(green). Photo by Verena Seidl (TU Vienna) and Nick Read (Univ. of Edinburgh).