title: Natural variation in timing of stress-responsive gene expression predicts heterosis in intraspecific hybrids of Arabidopsis.
abstract: The genetic distance between hybridizing parents affects heterosis; however, the mechanisms for this remain unclear. Here we report that this genetic distance correlates with natural variation and epigenetic regulation of circadian clock-mediated stress responses. In intraspecific hybrids of Arabidopsis thaliana, genome-wide expression of many biotic and abiotic stress-responsive genes is diurnally repressed and this correlates with biomass heterosis and biomass quantitative trait loci. Expression differences of selected stress-responsive genes among diverse ecotypes are predictive of heterosis in their hybrids. Stress-responsive genes are repressed in the hybrids under normal conditions but are induced to mid-parent or higher levels under stress at certain times of the day, potentially balancing the tradeoff between stress responses and growth. Consistent with this hypothesis, repression of two candidate stress-responsive genes increases growth vigour. Our findings may therefore provide new criteria for effectively selecting parents to produce high- or low-yield hybrids.
authors.affiliation: Departments of Molecular Biosciences and of Integrative Biology, Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Marisa
authors.initials: M
authors.lastname: Miller
authors.affiliation: Departments of Molecular Biosciences and of Integrative Biology, Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Qingxin
authors.initials: Q
authors.lastname: Song
authors.affiliation: Departments of Molecular Biosciences and of Integrative Biology, Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Shi
authors.affiliation: Departments of Molecular Biosciences and of Integrative Biology, Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Juenger
authors.affiliation: 1] Departments of Molecular Biosciences and of Integrative Biology, Center for Computational Biology and Bioinformatics, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, Texas 78712, USA [2] State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing 210095, China.
authors.forename: Z Jeffrey
authors.initials: ZJ
authors.lastname: Chen
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D018533:Biomass; D002940:Circadian Rhythm / Q000502:physiology; D044127:Epigenesis, Genetic; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D006823:Hybrid Vigor / Q000235:genetics / Q000502:physiology*; D006824:Hybridization, Genetic; D013312:Stress, Physiological / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins