Pyramiding of two rice bacterial blight resistance genes, Xa3 and Xa4, and a closely linked cold-tolerance QTL on chromosome 11.
We fine mapped the Xa4 locus and developed a pyramided rice line containing Xa3 and Xa4 R - alleles and a cold-tolerance QTL. This line will be valuable in rice breeding. Bacterial blight (BB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a destructive disease of cultivated rice. Pyramiding BB resistance genes is an essential approach for increasing the resistance level of rice varieties. We selected an advanced backcross recombinant inbred line 132 (ABL132) from the BC3F7 population derived from a cross between cultivars Junam and IR72 by K3a inoculation and constructed the mapping population (BC4F6) to locate the Xa4 locus. The Xa4 locus was found to be delimited within a 60-kb interval between InDel markers InDel1 and InDel2 and tightly linked with the Xa3 gene on chromosome 11. After cold (4 °C) treatment, ABL132 with introgressions of IR72 in chromosome 11 showed lower survival rate, chlorophyll content, and relative water content compared to Junam. Genetic analysis showed that the cold stress-related quantitative trait locus (QTL) qCT11 was located in a 1.3-Mb interval close to the Xa4 locus. One line, ABL132-36, containing the Xa3 resistance allele from Junam, the Xa4 resistance allele from IR72, and the cold-tolerance QTL from Junam (qCT11), was developed from a BC4F6 population of 250 plants. This is the first report on the pyramiding of Xa3 and Xa4 genes with a cold-tolerance QTL. This region could provide a potential tool for improving resistance against BB and low-temperature stress in rice-breeding programs.
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Yeon-Jae
YJ
Hur
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Jun-Hyeon
JH
Cho
National Institute of Crop Science, RDA, Wanju, 55365, Korea.
Hyun-Su
HS
Park
National Institute of Crop Science, RDA, Wanju, 55365, Korea.
Tae-Hwan
TH
Noh
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Dong-Soo
DS
Park
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Ji Yun
JY
Lee
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Young-Bo
YB
Sohn
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Dongjin
D
Shin
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
You Chun
YC
Song
National Institute of Crop Science, RDA, Miryang, 50424, Korea.
Young-Up
YU
Kwon
Research Policy Bureau, RDA, Jeonju, 54875, Korea. ccriljh@korea.kr.
Jong-Hee
JH
Lee
D000483:Alleles; D003080:Cold Temperature; D060467:Disease Resistance / Q000235:genetics*; D017343:Genes, Plant; D005819:Genetic Markers; D054643:INDEL Mutation; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D020161:Physical Chromosome Mapping; D000069600:Plant Breeding; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D040641:Quantitative Trait Loci; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics*; D014974:Xanthomonas
D005819:Genetic Markers; D020794:Receptor Protein-Tyrosine Kinases; C486360:Xa26 protein, Oryza sativa