LAUSR

A resistance gene pair balances immunity against crop yield The blast fungus Magnaporthe oryzae (Pyricularia oryzae) destroys rice crops worldwide (see the photo) (1) and now threatens global wheat production as well. Wheat blast disease has been spreading in South America since 1985, and last year it devastated wheat crops in Bangladesh (2, 3). Incorporation of resistance (R) genes into rice presents an effective, economical, and environmentally sound way to control blast (4). However, it takes years to move an R gene into a rice variety, whereas the highly variable fungus can overcome the R gene effects within 2 or 3 years after planting. Also, many R genes are associated with yield losses, so farmers often prefer rice varieties without R genes. On page 962 of this issue, Deng et al. (5) report a new R gene that comes with a homologous partner to counteract the yield penalty.