'To degrade or not to degrade?' - the emerging question in plant disease resistance

摘要

During plant pathogen interactions, resistance responses are activated when plant resistance (R) genes correspond to pathogen avirulence (avr) genes. The proteins encoded by R genes are thought to recognize Avr proteins, directly or indirectly, and activate signalling networks leading to resistance responses. Although several signalling components have been identified, the mechanisms by which they activate defence arc poorly understood. Recent studies in barley and Arabidopsis showed that RAR1 and SGT1 are each vital for resistance mediated by several R proteins [2, 3, 18, 25, 28, 29]. These findings have now been extended in Nicotiana where the role of SGT1 in disease resistance was shown to be more general [20]. SGT1 associates with a ubiquitin ligase complex and there is cumulative evidence that ubiquitylation plays an important role in plant disease resistance [3, 15].