APS Abstracts of Presentations
Redox regulation of Monilinia fructicola cutinase expression and
germ tube development. M. H. LEE, S. M. Marek, and R. M. Bostock. Dept.
Plant Pathology, University of California, Davis, CA 95616. Publication no.
P-2002-0672-AMA.
Monilinia fructicola causes brown rot blossom blight and fruit rot in
stone fruits. Immature fruit are highly resistant to brown rot but can become
infected. These infections typically remain superficial and quiescent until
they become active upon maturation of the fruit. High levels of chlorogenic
acid (CGA) and related compounds occur in the peel of immature fruit but these
levels decline during ripening. CGA inhibits cutinase expression, a putative
virulence factor, with little or no effect on spore germination or hyphal
growth. To better understand the regulation of cutinase expression by fruit
phenolics, we examined the effect of CGA, caffeic acid (CA) and related
compounds on the redox potential of the growth medium and intracellular
glutathione (GSH) levels. The presence of CA in the medium initially lowered
the electrochemical redox potential of the medium, increased GSH levels and
inhibited cutinase expression. Conidia germinated in the presence of CA, CGA,
or GSH produced fewer appressoria and had elongated germ tubes compared to the
controls. Host redox compounds seem to regulate fungal infectivity.
|
Back
