Tobacco Rar1, EDS1 and NPR1/NIM1 like genes are required for N‐mediated resistance to tobacco mosaic virus

Abstract

SummaryThe tobacco N gene confers resistance to tobacco mosaic virus (TMV) and encodes a Toll-interleukin-1 receptor/nucleotide binding site/leucine-rich repeat (TIR-NBS-LRR) class protein. We have developed and used a tobacco rattle virus (TRV) based virus induced gene silencing (VIGS) system to investigate the role of tobacco candidate genes in the N-mediated signalling pathway. To accomplish this we generated transgenic Nicotiana benthamiana containing the tobacco N gene. The transgenic lines exhibit hypersensitive response (HR) to TMV and restrict virus spread to the inoculated site. This demonstrates that the tobacco N gene can confer resistance to TMV in heterologous N. benthamiana. We have used this line to study the role of tobacco Rar1-, EDS1-, and NPR1/NIM1-like genes in N-mediated resistance to TMV using a TRV based VIGS approach. Our VIGS analysis suggests that these genes are required for N function. EDS1-like gene requirement for the N function suggests that EDS1 could be a common component of bacterial, fungal and viral resistance signalling mediated by the TIR-NBS-LRR class of resistance proteins. Requirement of Rar1-like gene for N-mediated resistance to TMV and some powdery mildew resistance genes in barley provide the ®rst example of converging points in the disease resistance signalling pathways mediated by TIR-NBS-LRR and CC-NBS-LRR proteins. The TRV based VIGS approach as described here to study N-mediated resistance signalling will be useful for the analysis of not only disease resistance signalling pathways but also of other signalling pathways in genetically intractable plant systems.

Two linked pairs of Arabidopsis TNL resistance genes independently confer recognition of bacterial effector AvrRps4

“…No HR was observed in the Ws-2 eds1-1 mutant, suggesting that RRIR is mediated by a TNL R protein ( Fig. 1) 25,26 . Interestingly, Pf Pf0-1 (PopP2) does not trigger HR in rrs1-1 or rps4-21, indicating that the RRIR is specific to AvrRps4 (ref.…”

A single locus confers tolerance to continuous light and allows substantial yield increase in tomato

“…The parameter F v /F m represents the maximum quantum efficiency of PSII; therefore, the lower the F v /F m value, the higher the injury is. The tomato CAB-13 gene consists of three exons; a unique region from exon 3 was cloned into the VIGS vector pTRV 27,28 (Fig. 2a).…”

Recognition and signal transduction in the expression of Phytophthora resistance in soybean [Glycine max (L) Merr]

“…Mutational screens for genes required in RPM1-mediated recognition and signal transduction identified AtRAR1, the Arabidopsis ortholog of barley RAR1, and it is allelic to the previously identified PBS2 (Warren et al 1999). Homolog of Rar1 in Nicotiana benthamiana plays a conserved role for the N gene function (Liu et al 2002a). Thus, RAR1 acts as an early common player in mediating resistance for multiple diverse R genes.…”

“…RAR1 interacts with SGT1b, ortholog of an essential regulator SGT1 for cell cycle in yeast (Azevedo et al, 2002). Both SGT1 and the RAR1-SGT1 complex interact with a ubiquitin ligase complex, which indicate that they may be involved in disease resistance related protein degradation pathways (Azevedo et al, 2002;Liu et al, 2002a;Peart et al, 2002). Several recent studies have also found that RAR1 and SGT1 are associated with the molecular chaperon HSP90 (Hubert et al, 2003;Liu et al, 2004;Liu et al, 2003;Takahashi et al, 2003).…”

“…In Arabidopsis, NDR1 and EDS1 are required for CC-NB-LRR and TIR-NB-LRR R proteins, respectively (Aarts et al, 1998;. RAR1 plays a conserved role in both types of NB-LRR R proteins (Azevedo et al, 2002;Liu et al, 2002a;Warren et al, 1999). RAR1 interacts with SGT1b, ortholog of an essential regulator SGT1 for cell cycle in yeast (Azevedo et al, 2002).…”