1.8.41
ANALYSIS OF TWO DIFFERENTIALLY EXPRESSED BOTRYTIS CINEREA GENES DURING INFECTION OF TOMATO

T PRINS, L WAGEMAKERS and JAL VAN KAN

Department of Phytopathology, Wageningen Agricultural University, PO Box 8025, 6700 EE Wageningen, The Netherlands

Background and objectives
The Ascomycete Botrytis cinerea, grey mould, causes severe pre- and post-harvest crop losses in a wide range of ornamentals and other plants, but there is a lack of fundamental insight into molecular aspects of the infection processes. By definition, a prerequisite for pathogenicity factors is that they are expressed during penetration and invasion of the host plant. Examples of such factors could be genes coding for extracellular hydrolases (cutinase, pectolytic enzymes), toxins or other, as yet unidentified genes.

In the B. cinerea-tomato interaction, some of the genes expressed during infection are aspartic protease (AP) and glutathione S-transferase (GST). Since GST is known to be involved in scavenging superoxide radicals during the oxidative burst, the regulation of this enzyme may play an important role in the defence system of the fungus. Aspartic proteases have been widely implicated as pathogenicity factors [1]. Proteinase activity can cause plant cell death, and higher levels were secreted by virulent compared with less virulent strains of Botrytis. This study could reveal whether proteinases have a significant role in pathogenicity.

Results and conclusion
Both the AP and GST genes have been sequenced, and expression studies of GST cDNA will be performed in the PFLAG system. Subsequently, GST will be analysed at the protein level. We are now working on disrupting these genes in B. cinerea B05.10, and putative transformants are currently being analysed. The first results of this screening and protein data of GST will be presented.

References
1. Movahedi S, Heale JB, 1990. Physiological and Molecular Plant Pathology 36, 289-302.