[compost_tea] PARASITISM OF TRICHODERMA ON ROOT-KNOT NEMATODES
I like trichoderma more and more..
190. PARASITISM OF TRICHODERMA ON ROOT-KNOT NEMATODES - MECHANISMS AND
IMPROVED
BIOCONTROL
E. Sharon1, I. Chet2 and Y. Spiegel1
1Division of Nematology , ARO, Volcani Center, P.O.B. 6, Bet-Dagan 50250,
Israel
2Department of Biological Chemistry, Weizmann Institute of Science, Israel
vpshedna_at_volcani.agri.gov.il
The fungus Trichoderma harzianum (asperellum) exhibits biocontrol activity
against the root-knot nematode
Meloidogyne javanica. Direct fungal parasitism is one of various possible
mechanisms by which the fungus can act
against the nematode juveniles (J2) and eggs. The fungal hyphae coil around
the J2 and penetrate them, as well as
to nematode eggs. A constitutive GFP (green fluorescent protein)
-transformant was used to observe the fungal
parasitism on nematode eggs and juveniles, using laser scanning confocal
microscopy. The involvement of
proteolytic and chitinilytic enzymes in the process was demonstrated using
inductive GFP-fungal transformants.
The protease and chitinase genes turned on during the interaction between
the fungus and the nematodes. The
direct fungal parasitism process on the nematode in vitro could be improved
using antibodies. Antibodies against
root-knot nematodes, that label the surface of M. javanica J2 and eggs,
bound also to the fungal spores and
agglutinated them. The presence of these antibodies enhanced the attachment
of the spores to the nematodes.
This resulted in a significant enhancement of fungal parasitism on the
nematodes. Moreover, the binding of
antibodies to the spores enhanced their germination and thus improved the
fungal parasitism on the nematodes.
Received on Wed Oct 27 2004 - 22:27:43 EDT
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