Gene superfamily causes plant diseases

Blacksburg, Va. -- A U.S. research team said it has identified a giant superfamily of pathogenic genes involved in various plant diseases.

The scientists from the Virginia Bioinformatics Institute at the Virginia Polytechnic Institute said the Avh superfamily comprises genes found in the plant pathogens Phytophthora ramorum and Phytophthora sojae.

The pathogen genes produce effector proteins that manipulate how plant cells work in such a way as to make the plant hosts more susceptible to infection, the researchers said. The results suggest a single gene from a common ancestor of the both pathogen species has spawned hundreds of very different, fast-evolving genes that encode for the highly damaging effector proteins.

"The extraordinary speed with which the Avh genes are evolving suggests that these genes are key to the pathogens' ability to outwit the defense systems of the plants," said Professor Brett Tyler, who led the study.

The research appeared in the March 25 issue of The Proceedings of the National Academy of Sciences.

Copyright 2008 by United Press International.