25.シロイヌナズナ種子発芽の高温阻害を緩和あるいは促進する化合物の選抜(口頭発表)

概要

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Seasonal timing of seed germination is crucial for winter- and summer-annual seeds to establish vegetative and reproductive growth. The upper-limit temperature for germination of winter annual seeds gradually rise from spring to autumn, but their germination is suppressed by ambient high temperature during summer. This germination suppression by high temperature (thermoinhibition) enables the seeds to germinate in autumn. In this study, we selected chemicals which alleviate or enhance thermoinhibition of Arabidopsis seeds. We used three chemical libraries which containing un-annotated 12,000 diverse chemicals (Landscape2, Tripos), 280 natural compounds (TimTec) and annotated 2,000 chemicals (Spectrum, MicroSource) for the screening. We used tt3-1 seeds along with Columbia accession since the mutation enhances permeability of testa for the applied chemicals. Thermoinhibition resistant and thermoinhibition susceptible mutants seeds were also used. This screening allowed us to identify forty thermoinhibition alleviating chemicals including gibberellin. One of the chemicals induces germination ten times more effective than GA_3 at restrictive temperature condition. We also identified thermoinhibition-enhancing chemicals which do not inhibit germination of the seeds at optimal temperature conditions, in addition to known germination inhibitors such as abscisic acid and cycloheximide.
2009-10-06