Single amino acid alterations in Arabidopsis thaliana RCY1 compromise resistance to Cucumber mosaic virus, but differentially suppress hypersensitive response-like cell death
- 244 Downloads
Resistance to an yellow strain of Cucumber mosaic virus [CMV(Y)] in Arabidopsis thaliana ecotype C24 is conferred by the CC-NBS-LRR type R gene, RCY1. RCY1-conferred resistance is accompanied by a hypersensitive response (HR), which is characterized by the development of necrotic local lesion (NLL) at the site of infection that restricts viral spread. To further characterize the role of RCY1 in NLL formation we have identified six recessive CMV(Y)-susceptible rcy1 mutants, four of which contain single amino acid substitutions in RCY1: rcy1-2 contains a D to N substitution in the CC domain, rcy1-3 and rcy1-4 contain R to K and E to K substitutions, respectively, in the LRR domain, and rcy1-6 contains a W to C substitution in the NBS domain. The rcy1-5 and rcy1-7 contain nonsense mutations in the LRR and NBS domains, respectively. Although the virus systemically spread in all six rcy1 mutants, HR-associated cell death was differentially induced in these mutants. In comparison to the wild type C24 plant, HR was not observed in the CMV(Y)-inoculated leaves of the rcy1-3, rcy1-5, rcy1-6 and rcy1-7 mutants. In contrast, delayed NLL development was observed in the virus inoculated leaves of the rcy1-2 and rcy1-4 mutants. In addition, necrosis accompanied by elevated accumulation of PR gene transcript also appeared in the non-inoculated leaves of the rcy1-2 and rcy1-4 mutants. Trans-complementation was observed between the rcy1-2 and rcy1-4 alleles; in F1 plants derived from a cross between rcy1-2 and rcy1−4, HR associated cell death was accelerated and systemic spread of the virus was partially suppressed than in the homozygous rcy1-2 and rcy1-4 plants. Our results suggest that the CC, NBS and LRR domains of RCY1 are required for restriction of virus spread but differentially impact the induction of HR-like cell death. Furthermore, these results also predict inter-molecular interaction involving RCY1 in Arabidopsis resistance to CMV(Y).
KeywordsResistance gene Gene-for-gene interaction Viral resistance
An yellow strain of Cucumber mosaic virus
Necrotic local lesion
RESISTANCE TO CMV(Y) 1
Unable to display preview. Download preview PDF.
This work was supported in part by a Grant-in-Aid for Scientific Research on Priority Areas (Molecular Mechanisms of Plant–Pathogenic Microbe Interaction – Toward Production of Disease Resistant Plants) and for Scientific Research (B) (16380031) from Ministry of Education, Culture, Sports and Arts, Japan.
- Bechtold N (1998) In planta Agrobacterium-mediated transformation of adult Arabidopsis thaliana plants by vacuum infiltration. In: Martinez-Zapater J, Salinas J. (eds) Methods in Molecular Biology. Humana Press, Totowa NJ, pp. 259–266Google Scholar
- Matthews REF. 2002. Plant Virology, 4th edn, Academic Press, New York. Google Scholar
- Rédei GP, Koncz C (1992) Classical Mutagenesis. In: Koncz C, Chua N-H, Shell J (eds) Methods in Arabidopsis Research. World Scientific, Singapore, pp 16–82Google Scholar
- Sekine K-T, Nandi A, Ishihara T, Hase S, Ikegami M, Shah J, Takahashi H (2004) Enhanced resistance to Cucumber mosaic virus in the Arabidopsis thaliana ssi2 mutant is mediated via an SA-independent mechanism. Mol. Plant-Microbe Interact 17:623–632Google Scholar
- Takahashi H, Kanayama Y, Zheng MS, Kusano T, Hase S, Ikegami M, Shah J (2004a) Antagonistic interactions between the SA and JA signaling pathways in Arabidopsis modulate expression of defense genes and gene-for-gene resistance to Cucumber mosaic virus. Plant Cell Physiol 45:803–809CrossRefGoogle Scholar
- Takahashi H, Miller J, Nozaki Y, Sukamto, Takeda M, Shah J, Hase S, Ikegami M, Ehara Y, Dinesh-Kumar SP (2002) RCY1, an Arabidopsis thaliana RPP8/HRT family resistance gene, conferring resistance to cucumber mosaic virus requires salicylic acid, ethylene and a novel signal transduction mechanism. Plant J 32:655–667PubMedCrossRefGoogle Scholar
- Takahashi H, Sekine K-T, Ishihara T, Hase S, Ikegami M, Shah J (2004b) Signal transduction pathways governing resistance to Cucumber mosaic virus. In: Tsuyumu S, Leach JE, Shiraishi T, Wolpert T (eds) Genomics and Genetic Analysis of Plant Parasitism and Defense. APS Press, Saint Paul pp.185–194Google Scholar
- Tomaru K, Hidaka J (1960) Strains of cucumber mosaic virus isolated from tobacco plants. III. A yellow strain. Bull. Hatano Tobacco Exp. Station 46:143–149Google Scholar