Dm3 is one member of a large constitutively expressed family of nucleotide binding site-leucine-rich repeat encoding genes

Katherine A. Shen, Doris B. Chin, Rosa Arroyo-Garcia, Oswaldo E. Ochoa, Dean O. Lavelle, Tadeusz Wroblewski, Blake C. Meyers, Richard W Michelmore

Research output: Contribution to journalArticle

74 Scopus citations

Abstract

The major cluster of resistance genes in lettuce cv. Diana contains approximately 32 nucleotide binding site-leucine-rich repeat encoding genes. Previous molecular dissection of this complex region had identified a large gene, RGC2B, as a candidate for encoding the downy mildew resistance gene, Dm3. This article describes genetic and transgenic complementation data that demonstrated RGC2B is necessary and sufficient to confer resistance with Dm3 specificity. Ethylmethanesulphonate was used to induce mutations to downy mildew susceptibility in cv. Diana (Dm1, Dm3, Dm7, and Dm8). Nineteen families were identified with a complete loss of resistance in one of the four resistance specificities. Sequencing revealed a variety of point mutations in RGC2B in the six dm3 mutants. Losses of resistance were due to single changes in amino acid sequence or a change in an intron splice site. These mutations did not cluster in any particular region of RGC2B. A full-length genomic copy of RGC2B was isolated from a lambdaphage library and introduced into two genotypes of lettuce. Transgenics expressing RGC2B exhibited resistance to all isolates expressing Avr3 from a wide range of geographical origins. In a wildtype Dm3-expressing genotype, many of the RGC2 family members are expressed at low levels throughout the plant.

Original languageEnglish (US)
Pages (from-to)251-261
Number of pages11
JournalMolecular Plant-Microbe Interactions
Volume15
Issue number3
StatePublished - 2002

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Biochemistry
  • Biotechnology
  • Microbiology

Fingerprint Dive into the research topics of 'Dm3 is one member of a large constitutively expressed family of nucleotide binding site-leucine-rich repeat encoding genes'. Together they form a unique fingerprint.

  • Cite this

    Shen, K. A., Chin, D. B., Arroyo-Garcia, R., Ochoa, O. E., Lavelle, D. O., Wroblewski, T., Meyers, B. C., & Michelmore, R. W. (2002). Dm3 is one member of a large constitutively expressed family of nucleotide binding site-leucine-rich repeat encoding genes. Molecular Plant-Microbe Interactions, 15(3), 251-261.