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Sequence variation at the rice blast resistance gene Pi-km locus: Implications for the development of allele specific markers

Permanent URL:
http://handle.nal.usda.gov/10113/42901
File:
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Abstract:
The recently cloned blast resistance (R) gene Pi-km protects rice crops against specific races of the fungal pathogen Magnaporthe oryzae in a gene-for-gene manner. The use of blast R genes remains the most cost-effective method for an integrated disease management strategy. To facilitate rice breeding we developed a Pi-km specific DNA marker. For this purpose, we initially explored the existing sequence diversity for alleles of the two genes responsible for the Pi-km specificity. The analysis of 15 rice cultivars revealed that the majority of nucleotide polymorphisms were associated with the Pi-km1 gene. Interestingly, the correspondent amino acid variation was localized within the predicted coiled-coil domain of the putative Pi-km1 protein. In contrast, the sequence of Pi-km2 alleles was highly conserved even within distantly related cultivars. Furthermore, disease reactions of the selected cultivars to five M. oryzae isolates, as well as their determined Pi-km1 allele, showed a good correlation with the known Pi-k genes (-k/-kh/-km/-ks/-kp) historically reported for these cultivars. Based on these findings, specific primer sets have been designed to discriminate among the various Pi-km alleles. The new markers should simplify the introgression of the valuable blast resistance associated with the complex Pi-k locus into rice cultivars.
Author(s):
Costanzo, Stefano , Jia, Yulin
Subject(s):
Oryza sativa , rice , grain crops , Magnaporthe , plant pathogenic fungi , blast disease , disease resistance , genetic resistance , gene-for-gene relationship , disease control , plant breeding , genetic markers , nucleotide sequences , genetic variation , alleles , loci , cultivars , genetic polymorphism , amino acid sequences , protein subunits , protein conformation , introgression
Format:
p. 523-530.
Note:
Includes references
Source:
Plant science 2010 June, v. 178, no. 6
Language:
English
Publisher:
[Ireland]: Elsevier Science Ireland Ltd.
Year:
2010
Collection:
Journal Articles, USDA Authors, Peer-Reviewed
Rights:
Works produced by employees of the U.S. Government as part of their official duties are not copyrighted within the U.S. The content of this document is not copyrighted.