Open AccessRice pollen hybrid incompatibility caused by reciprocal gene loss of duplicated genes
Author(s) -
Yoko Mizuta,
Yoshiaki Harushima,
Nori Kurata
Publication year - 2010
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.1003124107
Subject(s) - biology , genetics , gene duplication , gene , genome , japonica , allele , botany
Genetic incompatibility is a barrier contributing to species isolation and is caused by genetic interactions. We made a whole genome survey of two-way interacting loci acting within the gametophyte or zygote using independence tests of marker segregations in an F2 population from an intersubspecific cross betweenO. sativa subspeciesindica andjaponica . We detected only one reproducible interaction, and identified paralogous hybrid incompatibility genes,DOPPELGANGER1 (DPL1 ) andDOPPELGANGER2 (DPL2 ), by positional cloning. Independent disruptions ofDPL1 andDPL2 occurred inindica andjaponica , respectively.DPL s encode highly conserved, plant-specific small proteins (∼10 kDa) and are highly expressed in mature anther. Pollen carrying two defectiveDPL alleles became nonfunctional and did not germinate, suggesting an essential role forDPL s in pollen germination. Although rice has many duplicated genes resulting from ancient whole genome duplication, the origin of this gene duplication was in recent small-scale gene duplication, occurring afterOryza -Brachypodium differentiation. Comparative analyses suggested the geographic and phylogenetic distribution of these two defective alleles, showing that loss-of-function mutations ofDPL1 genes emerged multiple times inindica and its wild ancestor,O. rufipogon , and that theDPL2 gene defect is specific tojaponica cultivars.