title: A two-locus interaction causes interspecific hybrid weakness in rice.
abstract: Reproductive barriers perform a vital role during speciation. Hybrid weakness, the poorer development of hybrids compared with their parents, hinders gene exchange between different species at the postzygotic stage. Here we show that two incompatible dominant loci (Hwi1 and Hwi2) involving three genes are likely to determine the high temperature-dependent expression of hybrid weakness in interspecific hybrids of rice. Hwi1 comprises two leucine-rich repeat receptor-like kinase (LRR-RLK) genes, 25L1 and 25L2, which are specific to wild rice (Oryza rufipogon) and induce hybrid weakness. Hwi2, a rare allele that is predominantly distributed in indica rice (Oryza sativa), encodes a secreted putative subtilisin-like protease. Functional analysis indicated that pyramiding of Hwi1 and Hwi2 activates the autoimmune response in the basal nodes of hybrids, interrupting root formation and then impairing shoot growth. These findings bring new insights into our understanding of reproductive isolation and may benefit rice breeding.
authors.affiliation: 1] National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China [2].
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: 1] National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China [2].
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.affiliation: 1] Centre for Cell and Developmental Biology, School of Life Sciences, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China [2].
authors.forename: You-Shun
authors.initials: YS
authors.lastname: Lin
authors.affiliation: Centre for Cell and Developmental Biology, School of Life Sciences, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Jin-Bo
authors.initials: JB
authors.lastname: Shen
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Jun-Xiang
authors.initials: JX
authors.lastname: Shan
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Qi
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Min
authors.initials: M
authors.lastname: Shi
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Mei-Zhen
authors.initials: MZ
authors.lastname: Zhu
authors.affiliation: National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
authors.forename: Xue-Hui
authors.initials: XH
authors.lastname: Huang
authors.affiliation: National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Feng
authors.affiliation: National Center for Gene Research, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200233, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.affiliation: Centre for Cell and Developmental Biology, School of Life Sciences, Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China.
authors.forename: Liwen
authors.initials: L
authors.lastname: Jiang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Ji-Ping
authors.initials: JP
authors.lastname: Gao
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, National Center for Plant Gene Research (Shanghai), Shanghai Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Hong-Xuan
authors.initials: HX
authors.lastname: Lin
mesh_terms: D001947:Breeding; D006824:Hybridization, Genetic / Q000235:genetics / Q000502:physiology*; D012275:Oryza / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D010940:Plant Proteins