title: Genetic and physiological analysis of a novel type of interspecific hybrid weakness in rice.
abstract: Hybrid weakness is an important reproductive barrier that hinders genetic exchange between different species at the post-zygotic stage. However, our understanding of the molecular mechanisms underlying hybrid weakness is limited. In this study, we report discovery of a novel interspecific hybrid weakness in a rice chromosome segment substitution line (CSSL) library derived from a cross between the indica variety Teqing (Oryza sativa) and common wild rice (O. rufipogon). The dominant Hybrid weakness i1 (Hwi1) gene from wild rice is genetically incompatible with Teqing and induced a set of weakness symptoms, including growth suppression, yield decrease, impaired nutrient absorption, and the retardation of crown root initiation. Phytohormone treatment showed that salicylic acid (SA) could restore the height of plants expressing hybrid weakness, while other phytohormones appear to have little effect. Fine mapping indicated that Hwi1 is located in a tandem leucine-rich repeat receptor-like kinase (LRR-RLK) gene cluster. Within the 13.2-kb candidate region on the short arm of chromosome 11, there are two annotated LRR-RLK genes, LOC_Os11g07230 and LOC_Os11g07240. The Teqing allele of LOC_Os11g07230 and the wild rice allele of LOC_Os11g07240 encode predicted functional proteins. Based on the genetic inheritance of hybrid weakness, LOC_Os11g07240 is implicated as the candidate gene for Hwi1. Functional analysis of Hwi1 will expand our knowledge of the regulation of hybrid weakness in rice.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics and 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: Chen
authors.initials: C
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Chen
authors.forename: Jun-Xiang
authors.initials: JX
authors.lastname: Shan
authors.forename: Mei-Zhen
authors.initials: MZ
authors.lastname: Zhu
authors.forename: Min
authors.initials: M
authors.lastname: Shi
authors.forename: Ji-Ping
authors.initials: JP
authors.lastname: Gao
authors.forename: Hong-Xuan
authors.initials: HX
authors.lastname: Lin
mesh_terms: D060467:Disease Resistance / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D056726:Genetic Association Studies; D006824:Hybridization, Genetic / Q000187:drug effects; D007178:Inbreeding; D007477:Ions / Q000378:metabolism; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D010641:Phenotype; D010802:Phylogeny; D020161:Physical Chromosome Mapping; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012717:Sesquiterpenes / Q000378:metabolism; D013045:Species Specificity; D013997:Time Factors; D000094162:Phytoalexins
chemical_list: D007477:Ions; D010937:Plant Growth Regulators; D012717:Sesquiterpenes; D000094162:Phytoalexins