Efficacy of microorganisms antagonistic to Rhizoctonia cerealis and their cell wall degrading enzymatic activities.
The effect of Trichoderma atroviride, T. harzianum, T. longibrachiatum, Clonostachys rosea and Bacillus subtilis isolates applied to wheat seeds against Rhizoctonia cerealis disease of seedlings was investigated under controlled greenhouse conditions. Most Trichoderma isolates significantly reduced the incidence of disease compared with the infected control. Bacillus subtilis was also effective against sharp eyespot, although less active than Trichoderma spp. Interactions between the antagonistic microorganisms and the cereal pathogenic fungus in dual culture experiments on agar growth medium were also studied. Almost all tested antagonists showed competitive activity against R. cerealis: inhibition of its mycelial growth and hyphal interaction. The production of extracellular beta-N-acetylhexosaminidase, chitin 1,4-beta-chitobiosidase, glucan 1,3-beta-glucosidase and protease activity by the tested microorganisms in the presence of cell walls of R. cerealis was then determined. All isolates showed glucosaminidase and chitobiosidase activity. They also produced glucosidase activity, except B. subtilis, whereas only C. rosea, B. subtilis and one isolate of T. harzianum showed detectable levels of protease activity.
Innocenti
Gloria
G
Dipartimento di Protezione Valorizzazione Agroalimentare, Alma Mater Studiorum-University of Bologna, via Fanin, 46 40127 Bologna, Italy. innocent@agrsci.unibo.it
Roberti
Roberta
R
Montanari
Matteo
M
Zakrisson
Eva
E
D000898:Antibiosis; D001412:Bacillus subtilis / Q000201:enzymology / Q000502:physiology*; D001487:Basidiomycota / Q000166:cytology / Q000472:pathogenicity / Q000502:physiology*; D001673:Biodegradation, Environmental; D002473:Cell Wall / Q000378:metabolism; D010450:Endopeptidases / Q000096:biosynthesis / Q000378:metabolism; D004790:Enzyme Induction; D020462:Gliocladium / Q000201:enzymology / Q000502:physiology*; D005959:Glucosidases / Q000096:biosynthesis / Q000378:metabolism; D006596:Hexosaminidases / Q000096:biosynthesis / Q000378:metabolism; D036226:Seedlings / Q000166:cytology / Q000382:microbiology; D014242:Trichoderma / Q000201:enzymology / Q000502:physiology*; D014908:Triticum / Q000382:microbiology*
C079639:1,4-beta-chitobiosidase; D005959:Glucosidases; D006596:Hexosaminidases; D010450:Endopeptidases