Heterosis of Arabidopsis C24 x Col hybrids is associated with increased photosynthesis capacity.
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ABSTRACT: Arabidopsis thaliana shows hybrid vigour (heterosis) in progeny of crosses between Col and C24 accessions (1). Hybrid vigour was evident as early as the mature seeds and in the seedlings 3 days after sowing (DAS). At 3 DAS genes encoding chloroplast-located proteins were significantly overrepresented (187) among the 724 genes which have greater than mid parent values of expression in the hybrid. Many of these genes are involved in chlorophyll biosynthesis and photosynthesis. The rate of photosynthesis was constant per unit leaf area in parents and hybrids. Larger cell sizes in the hybrids were associated with more chloroplasts per cell, more total chlorophyll and more photosynthesis. The increased transcription of the chloroplast-targeted genes was restricted to the 3 to 7 DAS period. At 10 DAS only 118 genes had expression levels different from the expected mid parent value in the hybrid and only 12 of these genes were differentially expressed at 3 DAS. The early increase in activity of genes involved in photosynthesis and the associated phenomena of increase in cell size and number through development, leading to larger leaf areas of all leaves in the hybrid, suggest a central role for increased photosynthesis in the production of the heterotic biomass. In support of this correlation we found that an inhibitor of photosynthesis eliminated heterosis and higher light intensities enhanced both photosynthesis and heterosis. In hybrids with low level heterosis (Ler x Col) chloroplast-targeted genes were not upregulated and leaf areas were only marginally increased.
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE36273 | GEO | 2012/03/06
SECONDARY ACCESSION(S): PRJNA153107
REPOSITORIES: GEO
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