Os11g0208900
Os05g0107700, named as xa5, is a recessive gene associated with resistance to rice bacterial leaf blight.
Contents
Annotated Information
Function
Xa3/Xa26 mediates resistance to bacterial blight, a disease caused by Xanthomonas oryzae pv. oryzae (Xoo), which is a significant agronomic problem in rice-growing regions.The rice disease resistance (R) gene Xa3/Xa26 (having also been named Xa3 and Xa26) against Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial blight disease, belongs to a multiple gene family clustered in chromosome 11 and is from an AA genome rice cultivar (Oryza sativa L.). This family encodes leucine-rich repeat (LRR) receptor kinasetype proteins. Asian-cultivated rice consists of two major subspecies, indica (O. sativa L. ssp. indica) and japonica (O. sativa L. ssp. japonica).
Expression
The indica plants carrying Xa3/Xa26 were highly susceptible in four-leaf stage, but become resistant or moderately resistant to these Xoo races at booting stage. The development-controlled Xa3/Xa26 activity is also associated with its expression level (Cao et al. 2007).
Evolution
The orthologs (alleles) of Xa3/Xa26, Xa3/Xa26-2, and Xa3/Xa26-3, from wild Oryza species O. officinalis (CC genome) and O. minuta (BBCC genome), respectively, were also R genes against Xoo. Xa3/Xa26-2 and Xa3/Xa26-3 conferred resistance to 16 of the 18 Xoo strains examined. Comparative sequence analysis of the Xa3/Xa26 families in the two wild Oryza species showed that Xa3/Xa26-3 appeared to have originated from the CC genome of O. minuta. The predicted proteins encoded by Xa3/Xa26, Xa3/Xa26-2, and Xa3/Xa26-3 share 91–99% sequence identity and 94–99% sequence similarity.
Knowledge Extension
Xa3/Xa26 was first identified in the indica rice cultivar Minghui 63 and named Xa26. Further study revealed that Xa3, an R gene conferring resistance against Xoo, and Xa26 are actually the same gene and then it was renamed Xa3/Xa26. Xa3/Xa26 has been an important resistance gene for both indica and japonica rice production in China for a long time.
Labs working on this gene
- Department of Plant Breeding and Genetics, Cornell University, Ithaca, NY 14853, USA.
References
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