AY986492

Function

Resistant and susceptible alleles of Xa27 encode identical proteins. However, expression of only the resistant allele occurs when a rice plant is challenged by bacteria harbouring avrXa27, whose product is a nuclear localized type-III effector. Induction of Xa27 occurs only in the immediate vicinity of infected tissue, whereas ectopic expression of Xa27 resulted in resistance to otherwise compatible strains of the pathogen. Thus Xa27 specificity towards incompatible pathogens involves the differential expression of the R gene in the presence of the AvrXa27 effector.

Expression

The Xa27(t) locus conferred a high level of resistance to 27 strains and moderate resistance to three strains. Resistance of the Xa27(t) gene was developmentally regulated in IRBB27 and showed semidominant or a dosage effect in the cv. CO39 genetic background. As a prelude to cloning Xa27(t), a molecular mapping strategy was employed with a large mapping population consisting of 3,875 gametes

Evolution

Induction of Xa27 occurs only in the immediate vicinity of infected tissue, whereas ectopic expression of Xa27 resulted in resistance to otherwise compatible strains of the pathogen. Thus Xa27 specificity towards incompatible pathogens involves the differential expression of the R gene in the presence of the AvrXa27 effector.

Labs working on this gene

1. Temasek Life Sciences Laboratory, National University of Singapore, Singapore, 117604, Singapore

2. Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China

2. Rice Research Institute, Anhui Academy of Agricultural Sciences, Hefei, 230031, Anhui, China

References

1. Yanchang Luo;Jatinder S. Sangha;Shouhai Wang;Zefu Li;Jianbo Yang;Zhongchao Yin

 Marker-assisted breeding of Xa4, Xa21 and Xa27 in the restorer lines of hybrid rice for broad-spectrum and enhanced disease resistance to bacterial blight
 Molecular Breeding, 2012, 30(4): 1601-1610

2. Keyu Gu;Bing Yang;Dongsheng Tian;Lifang Wu;Dongjiang Wang;Chellamma Sreekala;Fan Yang;Zhaoqing Chu;Guo-Liang Wang;Frank F. White;Zhongchao Yin

 R gene expression induced by a type-III effector triggers disease resistance in rice
 Nature, 2005, 435: 1122-1125

3. K.Gu;D.Tian;F.Yang;L.Wu;C.Sreekala;D.Wang;G.-L.Wang;Z.Yin

 High-resolution genetic mapping of Xa27(t), a new bacterial blight resistance gene in rice, Oryza sativa L.
 Theoretical and Applied Genetics, 2004, 108(5): 800-807