Poster: Signaling, cell-to-cell
Abs #
427: Sugars and Phytohormones Regulate Seed Germination and Early Seedling Development via a Complex Signaling “Network”
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Presenter: |
Huang, Yadong , huan0277@umn.edu | Authors | Huang, Yadong (A) Pattison, Donna (B) Biddle, Kelly (B) Moon, Melissa (B) Gibson, Susan I. (A) | | Affiliations: |
(A): Department of Plant Biology, University Of Minnesota, 250 BioSciCtr, 1445 Gortner Avenue, St. Paul, MN 55108 USA
(B): Department of Biochemistry & Cell Biology, Rice University, 6100 Main Street, Houston, TX 77005 USA
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Plants undergo profound metabolic and developmental transitions during seed germination and early seedling development. Regulation of these transitions and other processes occurs via a complex signaling “network” that receives input from several chemical signals. These chemical signals have long been known to include abscisic acid, which inhibits seed germination, as well as ethylene and gibberellin, which promote seed germination. Recent work by our lab and others has shown that soluble sugars also affect seed germination. Even low to moderate concentrations of exogenous sugars (e.g. 30 mM glucose) cause a significant delay in the rate of germination of wild-type Arabidopsis. This effect is not due to alterations in the osmotic potential of the media, as even substantially higher concentrations of sorbitol do not exert similar effects. Several lines of evidence also suggest that sugars and phytohormones “interact” in the regulation of seed germination. For example, several sugar-insensitive (sis) mutants of Arabidopsis also exhibit alterations in phytohormone response and/or metabolism. The sis1 mutant is allelic to the ethylene constitutive response mutant, ctr1. The sis4 mutant is allelic to the abscisic acid deficient mutant, aba2, and the sis5 mutant is allelic to the abscisic acid insensitive mutant, abi4. Finally, the sis2 mutant displays resistance to the gibberellin biosynthesis inhibitor paclobutrazol, suggesting that sis2 may be defective in gibberellin response or metabolism. Findings that exogenous glucose greatly exacerbates the negative effects of paclobutrazol on seed germination also suggest “interactions” between sugar and phytohormone response pathways. Possible models for these interactions will be discussed.
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