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  • An Allelic Variant of the Broad-Spectrum Blast Resistance Gene Ptr in Weedy Rice Is Associated with Resistance to the Most Virulent Blast Race IB-33
Title: An Allelic Variant of the Broad-Spectrum Blast Resistance Gene Ptr in Weedy Rice Is Associated with Resistance to the Most Virulent Blast Race IB-33
Rice resistance (R) genes have been effectively deployed to prevent blast disease caused by the fungal pathogen Magnaporthe oryzae, one of the most serious threats for stable rice production worldwide. Weedy rice competing with cultivated rice may carry novel or lost R genes. The quantitative trait locus qBR12.3b was previously mapped between two single nucleotide polymorphism markers at the 10,633,942-bp and 10,820,033-bp genomic positions in a black-hull-awned (BHA) weed strain using a weed-crop-mapping population under greenhouse conditions. In this study, we found a portion of the known resistance gene Ptr encoding a protein with four armadillo repeats and confers a broad spectrum of blast resistance. We then analyzed the sequences of the Ptr gene from weedy rice, PtrBHA, and identified a unique amino acid glutamine at protein position 874. Minor changes of protein conformation of the PtrBHAgene were predicted through structural analysis of PtrBHA, suggesting that the product of PtrBHAis involved in disease resistance. A gene-specific codominant marker HJ17-13 from PtrBHAwas then developed to distinguish alleles in weeds and crops. The PtrBHAgene existed in 207 individuals of the same mapping population, where qBR12.3b was mapped using this gene-specific marker. Disease reactions of 207 individuals and their parents to IB-33 were evaluated. The resistant individuals had PtrBHAwhereas the susceptible individuals did not, suggesting that HJ17-13 is reliable to predict qBR12.3b. Taken together, this newly developed marker, and weedy rice genotypes carrying qBR12.3b, are useful for blast improvement using marker assisted selection.  more » « less
Award ID(s):
1947609
PAR ID:
10492541
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Plant Disease
Date Published:
Journal Name:
Plant Disease
Volume:
106
Issue:
6
ISSN:
0191-2917
Page Range / eLocation ID:
1675 to 1680
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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