Science - March 31, 2005
Phytophthora like fungus after all
Plant pathologists have fought a bitter battle for years to grant Phytophthora infestans a separate status. They have asserted repeatedly that the cause of the dreaded potato blight is not a fungus but a type of oomycete, or water mould, more closely related to algae. A large-scale genetic analysis has now shown however that there are a number of remarkable similarities between Phytophthora and fungi.
Analyses of the ESTs showed that the genes of the Phytophthora that make potato plants sick, strongly resemble those of true fungi. ‘In one way it’s not really that surprising,’ says Govers. ‘After all it’s about the genes that are involved in breaking down cell walls.’ What is more remarkable is that Phytophthora also has a gene that enables it to make chitin. ‘We tell students that fungi always have chitin in their cell walls and oomycetes do not, but it’s not as simple as that. They are capable of making chitin, but do not always do so, or only in very small quantities.’/ GvM