Ubiquitin ligase-associated protein SGT1 is required for host and nonhost disease resistance in plants

Jack R. Peart, The Sainsbury Laboratory
Rui Lu, The Sainsbury Laboratory
Ari Sadanandom, The Sainsbury Laboratory
Isabelle Malcuit, The Sainsbury Laboratory
Peter Moffett, The Sainsbury Laboratory
David C. Brice, The Sainsbury Laboratory
Leif Schauser, The Sainsbury Laboratory
Daniel A.W. Jaggard, University of East Anglia
Shunyuan Xiao, University of East Anglia
Mark J. Coleman, University of East Anglia
Max Dow, The Sainsbury Laboratory
Jonathan D.G. Jones, The Sainsbury Laboratory
Ken Shirasu, The Sainsbury Laboratory
David C. Baulcombe, The Sainsbury Laboratory

Abstract

Homologues of the yeast ubiquitin ligase-associated protein SGT1 are required for disease resistance in plants mediated by nucleotide-binding site/leucine-rich repeat (NBS-LRR) proteins. Here, by silencing SGT1 in Nicotiana benthamiana, we extend these findings and demonstrate that SGT1 has an unexpectedly general role in disease resistance. It is required for resistance responses mediated by NBS-LRR and other R proteins in which pathogen-derived elicitors are recognized either inside or outside the host plant cell. A requirement also exists for SGT1 in nonhost resistance in which all known members of a host species are resistant against every characterized isolate of a pathogen. Our findings show that silencing SGT1 affects diverse types of disease resistance in plants and support the idea that R protein-mediated and nonhost resistance may involve similar mechanisms.