Transcriptomic response of the mycoparasitic fungus Trichoderma atroviride to the presence of a fungal prey.
BACKGROUND
Combating the action of plant pathogenic microorganisms by mycoparasitic fungi has been announced as an attractive biological alternative to the use of chemical fungicides since two decades. The fungal genus Trichoderma includes a high number of taxa which are able to recognize, combat and finally besiege and kill their prey. Only fragments of the biochemical processes related to this ability have been uncovered so far, however.


RESULTS
We analyzed genome-wide gene expression changes during the begin of physical contact between Trichoderma atroviride and two plant pathogens Botrytis cinerea and Rhizoctonia solani, and compared with gene expression patterns of mycelial and conidiating cultures, respectively. About 3000 ESTs, representing about 900 genes, were obtained from each of these three growth conditions. 66 genes, represented by 442 ESTs, were specifically and significantly overexpressed during onset of mycoparasitism, and the expression of a subset thereof was verified by expression analysis. The upregulated genes comprised 18 KOG groups, but were most abundant from the groups representing posttranslational processing, and amino acid metabolism, and included components of the stress response, reaction to nitrogen shortage, signal transduction and lipid catabolism. Metabolic network analysis confirmed the upregulation of the genes for amino acid biosynthesis and of those involved in the catabolism of lipids and aminosugars.


CONCLUSIONS
The analysis of the genes overexpressed during the onset of mycoparasitism in T. atroviride has revealed that the fungus reacts to this condition with several previously undetected physiological reactions. These data enable a new and more comprehensive interpretation of the physiology of mycoparasitism, and will aid in the selection of traits for improvement of biocontrol strains by recombinant techniques.
Seidl
Verena
V
Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, Vienna University of Technology, Getreidemarkt 9/166, A-1060 Vienna, Austria. vseidl@mail.zserv.tuwien.ac.at
Song
Lifu
L
Lindquist
Erika
E
Gruber
Sabine
S
Koptchinskiy
Alexeji
A
Zeilinger
Susanne
S
Schmoll
Monika
M
Martínez
Pedro
P
Sun
Jibin
J
Grigoriev
Igor
I
Herrera-Estrella
Alfredo
A
Baker
Scott E
SE
Kubicek
Christian P
CP
D020171:Botrytis / Q000502:physiology*; D030541:Databases, Genetic; D020224:Expressed Sequence Tags / Q000378:metabolism; D020869:Gene Expression Profiling; D015966:Gene Expression Regulation, Fungal; D015723:Gene Library; D005800:Genes, Fungal; D008027:Light; D053858:Metabolic Networks and Pathways; D010572:Pest Control, Biological; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012232:Rhizoctonia / Q000502:physiology*; D013172:Spores, Fungal / Q000235:genetics / Q000528:radiation effects; D014242:Trichoderma / Q000235:genetics* / Q000378:metabolism / Q000502:physiology*; D015854:Up-Regulation