Antagonism of Pythium blight of zucchini by Hypocrea jecorina does not require cellulase gene expression but is improved by carbon catabolite derepression.
Toward a better understanding of the biochemical events that lead to biocontrol of plant pathogenic fungi by Hypocrea/Trichoderma spp., we investigated the importance of carbon catabolite (de)repression and cellulase formation in the antagonization of Pythium ultimum by Hypocrea jecorina (Trichoderma reesei) on agar plates and in planta. Hypocrea jecorina QM9414 could antagonize and overgrow P. ultimum but not Rhizoctonia solani in plate confrontation tests, and provided significant protection of zucchini plants against P. ultimum blight in planta. A carbon catabolite derepressed cre1 mutant of H. jecorina antagonized P. ultimum on plates more actively and increased the survival rates of P. ultimum-inoculated zucchini plants in comparison with strain QM9414. A H. jecorina mutant impaired in cellulase induction could also antagonize P. ultimum on plates and provided the same level of protection of zucchini plants against P. ultimum as strain QM9414 did. We conclude that cellulase formation is dispensable for biocontrol of P. ultimum, whereas carbon catabolite derepression increases the antagonistic ability by apparently acting on other target genes.
Research Area Gene Technology and Applied Biochemistry, Institute of Chemical Engineering, TU Vienna, Vienna, Austria.
Verena
V
Seidl
Monika
M
Schmoll
Barbara
B
Scherm
Virgilio
V
Balmas
Bernhard
B
Seiboth
Quirico
Q
Migheli
Christian P
CP
Kubicek
D002244:Carbon / Q000378:metabolism; D002480:Cellulase / Q000235:genetics / Q000378:metabolism; D003470:Culture Media; D015966:Gene Expression Regulation, Fungal; D035901:Hypocrea / Q000201:enzymology / Q000254:growth & development*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000382:microbiology*; D011775:Pythium / Q000254:growth & development / Q000472:pathogenicity*; D014675:Vegetables / Q000382:microbiology*
D003470:Culture Media; D002244:Carbon; D002480:Cellulase