Rice ESTs with disease-resistance gene- or defense-response gene-like sequences mapped to regions containing major resis
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O R I GI N A L P A P E R
Z. Wang á G. Taramino á D. Yang á G. Liu S. V. Tingey á G.-H. Miao á G.-L. Wang
Rice ESTs with disease-resistance gene- or defense-response gene-like sequences mapped to regions containing major resistance genes or QTLs Received: 24 July 2000 / Accepted: 4 November 2000 / Published online: 23 February 2001 Ó Springer-Verlag 2001
Abstract The chromosomal locations of 109 rice expressed sequence tags (ESTs) in the rice genome were determined using a doubled haploid mapping population. These ESTs show high similarity to disease resistance genes or to defense response genes. Nine of the ESTs were mapped to three regions that contain genetically de®ned resistance genes on chromosomes 6 and 11. Clustering of the ESTs in the rice genome was observed at several chromosomal regions. Some of the clusters were located in regions where quantitative trait loci (QTL) associated with partial resistance to rice blast, bacterial blight and sheath blight are known to lie. Three ESTs that were mapped to the regions containing blast resistance genes Pi2 and Pia were chosen for Northern analysis after inoculation of plants with the blast fungus. Two of them, which code for a receptor-like kinase and a putative membrane channel protein, respectively, and were mapped to the Pi2 locus, were induced by rice blast infection as early as 4 h after inoculation. Transcription of another EST, which codes for a homolog of a putative human tumor suppressor and was mapped to the region containing Pia, was repressed after blast infection. These ®ndings demonstrate that the candidate-gene approach
Communicated by A. Kondorosi Z. Wang á D. Yang á G. Liu á G.-L. Wang (&) The Institute of Molecular Agrobiology, The National University of Singapore, 1 Research Link, 117604 Singapore E-mail: [email protected] Tel.: +1-614-2929280 Fax: +1-614-2924455 G. Taramino á S. V. Tingey á G.-H. Miao DuPont Agricultural Products, Genomics, Delaware Technology Park, S200, Newark, DE 19714-6104, USA G. Liu á G.-L. Wang Department of Plant Pathology, Ohio State University, Kottmann Hall, 2021 Coey Road, Columbus OH 43210-1087, USA
is an ecient way of mapping resistance genes or resistance QTLs in rice. Key words Expressed sequence tags (ESTs) á Resistance gene á Candidate gene approach á Oryza sativa á Quantitative trait loci (QTLs)
Introduction The plant disease resistance pathway consists of two major classes of genes: those involved in events associated with the recognition of, and interaction with, elicitor molecules from pathogens, and those involved in defense responses. In recent years, the successful cloning of more than 20 disease resistance genes in plants has dramatically advanced our understanding of the molecular basis of disease resistance. Sequence analysis of the predicted proteins reveals that resistance genes of diverse origin and with dierent pathogen speci®city share similar structural motifs, indicating that a common surveillance strategy has been adopted by plant species to detect invading pathogens. Based on the sim
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