MOLECULAR SIGNALS DURING THE EARLY STAGES OF ALFALFA ANTHRACNOSE

Colletotrichum trifolii causes anthracnose disease of alfalfa (Medicag o sativa). Fungal. perception and response to host signals are Likely to be crucial in determining whether successful infection occurs. Our research is based on two premises: (i) that early recognition events r esult in specific responses and these responses determine whether dise ase occurs and (ii) recognition involves signal exchange between host and pathogen. We have taken two approaches to study this interaction. One is to isolate ''important'' genes by methods that make no assumpti on about their products and then to use molecular characterization (e. g., sequence, expression pattern) to identify the biochemical processe s involved. Alternatively, known biochemical entities (genes) that fun ction in signal transduction in other organisms are used as heterologo us probes or primers. These molecules are then manipulated to determin e functional relevance to the host-pathogen. Data is presented from th e later approach and we show that calmodulin, protein kinase C, and a novel protein kinase are specifically expressed during the early stage s of infection.