Expression of the Bs2 pepper gene confers resistance to bacterial spot disease in tomato

Expression of the Bs2 pepper gene confers resistance to bacterial spot disease in tomato

^*Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720; ^§Department of Biology, San Francisco State University, San Francisco, CA 94132; and ^¶Department of Plant Pathology, University of Florida, Gainesville, FL 32611

Contributed by Brian J. Staskawicz

Abstract

The Bs2 resistance gene of pepper specifically recognizes and confers resistance to strains of Xanthomonas campestris pv. vesicatoria that contain the corresponding bacterial avirulence gene, avrBs2. The involvement of avrBs2 in pathogen fitness and its prevalence in many X. campestris pathovars suggests that the Bs2 gene may be durable in the field and provide resistance when introduced into other plant species. Employing a positional cloning strategy, the Bs2 locus was isolated and the gene was identified by coexpression with avrBs2 in an Agrobacterium-mediated transient assay. A single candidate gene, predicted to encode motifs characteristic of the nucleotide binding site–leucine-rich repeat class of resistance genes, was identified. This gene specifically controlled the hypersensitive response when transiently expressed in susceptible pepper and tomato lines and in a nonhost species, Nicotiana benthamiana, and was designated as Bs2. Functional expression of Bs2 in stable transgenic tomatoes supports its use as a source of resistance in other Solanaceous plant species.

Footnotes

↵ † Present address: Dale Bumpers National Rice Research Center, U.S. Department of Agriculture-ARS, Stuttgart, AR 72160.
↵ ‡ T.H.T. and D.D. contributed equally to this work.
↵ ‖ To whom reprint requests should be addressed. E-mail: stask{at}nature.berkeley.edu.
Data deposition: The sequence reported in this paper has been deposited in the GenBank database (accession no. AF202179).
Abbreviations:

NBS-LRR,

nucleotide binding site–leucine-rich repeat;

RTF,

restricted taxonomic functionality;

ECW,

Early Calwonder;

YAC,

yeast artificial chromosome;

HR,

hypersensitive reaction