A Breakdown in Defense Signaling
Plant Cell 14, S5-S8.

Dodds, PN and C Schwechheimer

"One of the major mechanisms that plants use to escape disease involves a pathogen recognition system known as gene-for-gene resistance. This is controlled genetically by resistance ( R ) genes in plants, which encode proteins that recognize avirulence (Avr) products of an invading pathogen. Pathogen recognition triggers a wide range of both local and systemic responses whose cumulative effect is the inhibition of pathogen growth. In the past decade, many R genes have been isolated that confer pathogen resistance to various plant species against a wide range of pathogens; however, the signaling processes that lead from initial pathogen recognition to the induction of the resistance response remain poorly understood (Glazebrook, 2001). Five exciting new articles address two downstream components of resistance signaling, RAR1 and SGT1 (Austin et al., 2002; Azevedo et al., 2002; Muskett et al., 2002, Tör et al., 2002; Tornero et al., 2002). Together, these articles provide critical evidence that protein degradation may be of pivotal importance for efficient pathogen responses and form the basis of a new paradigm for resistance signaling."