title: Intraspecific Arabidopsis hybrids show different patterns of heterosis despite the close relatedness of the parental genomes.
abstract: Heterosis is important for agriculture; however, little is known about the mechanisms driving hybrid vigor. Ultimately, heterosis depends on the interactions of specific alleles and epialleles provided by the parents, which is why hybrids can exhibit different levels of heterosis, even within the same species. We characterize the development of several intraspecific Arabidopsis (Arabidopsis thaliana) F1 hybrids that show different levels of heterosis at maturity. We identify several phases of heterosis beginning during embryogenesis and culminating in a final phase of vegetative maturity and seed production. During each phase, the hybrids show different levels and patterns of growth, despite the close relatedness of the parents. For instance, during the vegetative phases, the hybrids develop larger leaves than the parents to varied extents, and they do so by exploiting increases in cell size and cell numbers in different ratios. Consistent with this finding, we observed changes in the expression of genes known to regulate leaf size in developing rosettes of the hybrids, with the patterns of altered expression differing between combinations. The data show that heterosis is dependent on changes in development throughout the growth cycle of the hybrid, with the traits of mature vegetative biomass and reproductive yield as cumulative outcomes of heterosis at different levels, tissues, and times of development.
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: Michael
authors: M
authors: Groszmann
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: Rebeca
authors: R
authors: Gonzalez-Bayon
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: Ian K
authors: IK
authors: Greaves
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: Li
authors: L
authors: Wang
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: Amanda K
authors: AK
authors: Huen
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.).
authors: W James
authors: WJ
authors: Peacock
authors: Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.) liz.dennis@csiro.au.
authors: Elizabeth S
authors: ES
authors: Dennis
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D018533:Biomass; D002452:Cell Count; D048429:Cell Size; D047108:Embryonic Development; D005638:Fruit / Q000254:growth & development; D017343:Genes, Plant; D006823:Hybrid Vigor; D006824:Hybridization, Genetic; D018520:Plant Shoots / Q000254:growth & development