POTENTIAL ROLE OF ELICITINS IN THE INTERACTION BETWEEN PHYTOPHTHORA SPECIES AND TOBACCO

The potential role of extracellular elicitor proteins (elicitins) from Phytophthora species as avirulence factors in the interaction between Phytophthora and tobacco was examined. A Survey of 85 Phytophthora is olates representing 14 species indicated that production of elicitin i s almost ubiquitous except for isolates of Phytophthora parasitica fro m tobacco. The production of elicitins by isolates of P. parasitica co rrelated without exception with low or no virulence on tobacco. Geneti c analysis was conducted by using a cross between two isolates of P. p arasitica, segregating for production of elicitin and virulence on tob acco. Virulence assays of the progeny on tobacco confirmed the correla tion between production of elicitin and low virulence.