title: Functional divergence of duplicated genes results in a novel blast resistance gene Pi50 at the Pi2/9 locus.
abstract: We characterized a novel blast resistance gene Pi50 at the Pi2/9 locus; Pi50 is derived from functional divergence of duplicated genes. The unique features of Pi50 should facilitate its use in rice breeding and improve our understanding of the evolution of resistance specificities. Rice blast disease, caused by the fungal pathogen Magnaporthe oryzae, poses constant, major threats to stable rice production worldwide. The deployment of broad-spectrum resistance (R) genes provides the most effective and economical means for disease control. In this study, we characterize the broad-spectrum R gene Pi50 at the Pi2/9 locus, which is embedded within a tandem cluster of 12 genes encoding proteins with nucleotide-binding site and leucine-rich repeat (NBS-LRR) domains. In contrast with other Pi2/9 locus, the Pi50 cluster contains four duplicated genes (Pi50_NBS4_1 to 4) with extremely high nucleotide sequence similarity. Moreover, these duplicated genes encode two kinds of proteins (Pi50_NBS4_1/2 and Pi50_NBS4_3/4) that differ by four amino acids. Complementation tests and resistance spectrum analyses revealed that Pi50_NBS4_1/2, not Pi50_NBS4_3/4, control the novel resistance specificity as observed in the Pi50 near isogenic line, NIL-e1. Pi50 shares greater than 96 % amino acid sequence identity with each of three other R proteins, i.e., Pi9, Piz-t, and Pi2, and has amino acid changes predominantly within the LRR region. The identification of Pi50 with its novel resistance specificity will facilitate the dissection of mechanisms behind the divergence and evolution of different resistance specificities at the Pi2/9 locus.
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Su
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Wenjuan
authors.initials: W
authors.lastname: Wang
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.|College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
authors.forename: Jingluan
authors.initials: J
authors.lastname: Han
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Shen
authors.initials: S
authors.lastname: Chen
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Congying
authors.initials: C
authors.lastname: Wang
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Liexian
authors.initials: L
authors.lastname: Zeng
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Aiqing
authors.initials: A
authors.lastname: Feng
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China.
authors.forename: Jianyuan
authors.initials: J
authors.lastname: Yang
authors.affiliation: Plant Breeding, Genetics, and Biotechnology Division, International Rice Research Institute, DAPO Box 7777, 1031, Metro Manila, Philippines. b.zhou@irri.org.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhou
authors.affiliation: Guangdong Provincial Key Laboratory of High Technology for Plant Protection, Plant Protection Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, 510640, China. zhuxy@gdppri.com.
authors.forename: Xiaoyuan
authors.identifier: http://orcid.org/0000-0002-6365-0997
authors.initials: X
authors.lastname: Zhu
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018744:DNA, Plant / Q000235:genetics; D060467:Disease Resistance / Q000235:genetics*; D020131:Genes, Duplicate; D017343:Genes, Plant; D005816:Genetic Complementation Test; D020082:Magnaporthe / Q000472:pathogenicity; D008969:Molecular Sequence Data; D012275:Oryza / Q000235:genetics* / Q000382:microbiology; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D030821:Plants, Genetically Modified; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D018744:DNA, Plant