抄録
Phytophthora is a genus of oomycetes and one of the best known agricultural pests. The most notorious species of this genus is Phytophthora infestans, which causes the destructive potato blight disease responsible for the "Great Irish Famine" in the mid 1840s. Sexual reproduction of the heterothallic members require two strains designated as Al and A2 mating types, which secrete unique mating hormones αl and α2, respectively, and regulate sexual reproduction in the counter mating type. Although the chemical characterization of a hormunes had been a long-term issue, al was isolated and characterized by us in 2005. Here we describe the absolute stereostructure of the second mating hormone α2 by spectroscopic analysis and total synthesis. The hormone α2 was found to be a linear diterpene, which is similar to al. The interspecies universality of both αl and α2 in Phytophthora was then demonstrated by hormone response experiments and hormone production analysis with 45 heterothallic strains. In addition, stable isotope-labeling experiments revealed the pathway, in which α2 is biosynthesized from phytol by A2 mating type strains and metabolized to αl by Al.
