Disease relevance of RPS4

• RPS4, the closest homolog of CSA1, confers resistance to Pseudomonas syringae and complements the csa1 mutant phenotype, indicating that responses to pathogens and neighbors share core-signaling components in Arabidopsis [1].

High impact information on RPS4

• Arabidopsis PUB17 knockout plants are compromised in RPM1- and RPS4-mediated resistance against Pseudomonas syringae pv tomato containing avirulence genes AvrB and AvrRPS4, respectively [2].
• RPS4-mediated disease resistance requires the combined presence of RPS4 transcripts with full-length and truncated open reading frames [3].
• Arabidopsis RPS4 belongs to the Toll/interleukin-1 receptor (TIR)-nucleotide binding site (NBS)-Leu-rich repeat (LRR) class of disease resistance (R) genes [3].
• In addition, a truncated RPS4-Ler transgene encoding the putative TIR and NBS domains was not sufficient to confer resistance, suggesting that the combined presence of regular and alternative RPS4 transcripts is necessary for function [3].
• Removal of one or both introns abolished the function of the RPS4 transgene, whereas expression was not affected [3].

Biological context of RPS4

• The Arabidopsis RPS4 bacterial-resistance gene is a member of the TIR-NBS-LRR family of disease-resistance genes [4].
• The characterization of RPS4 presented here thus establishes a role for TIR-NBS-LRR R genes in resistance to bacterial pathogens, and provides evidence for the model that dependence of R genes on EDS1 is determined by R protein structure, and not by pathogen type [4].
• RPS4 is a disease-resistance locus on chromosome 5 of Arabidopsis thaliana specifying resistance to strains of Pseudomonas syringae pv. tomato expressing avrRps4 [4].
• Like other family members in different plant species, RPS4 produces alternative transcripts with truncated open reading frames [3].
• All these data suggest that heterologous expression of an R gene can result in activation of cell death even in the absence of its cognate avirulence product, and provides a system for studying the RPS4 domains required for HR [5].

Regulatory relationships of RPS4

• Expression of RPS4 in tobacco induces an AvrRps4-independent HR that requires EDS1, SGT1 and HSP90 [5].

Other interactions of RPS4

• Previous work has shown that RPS4, like other Arabidopsis TIR-NBS-LRR R genes specifying resistance to oomycetes, is dependent on a functional EDS1 allele for disease-resistance signaling [4].
• Incomplete splicing of the RPS4 mRNA was observed, which may give rise to truncated protein products consisting mainly of the TIR and NBS domains [4].

Analytical, diagnostic and therapeutic context of RPS4

• The cloning of RPS4 and the previous isolation of avrRps4 provide the molecular tools for a genetic and molecular dissection of the TIR-NBS-LRR R gene signaling pathway in Arabidopsis [4].

References