Submitted to: Annual Reviews of Plant Biology
Publication Type: Review Article
Publication Acceptance Date: 1/2/2008
Publication Date: 6/1/2008
Citation: Finkelstein, R., Reeves, W., Ariizumi, T., Steber, C.M. 2008. Molecular aspects of seed dormancy. Annu. Rev. Plant Biol. 59:387-415.
Interpretive Summary: Seed dormancy prevents the germination of living seed under conditions that normally promote seed germination. Dormancy helps to ensure germination in the proper season to allow plant survival and also helps plant species to survive catastrophes by allowing some seed of the species to survive in the soil. Seed dormancy is alleviated by storage under dry conditions (after-ripening) or by specific environmental effects such and exposure to moist chilling conditions. Dormancy and dormancy-breading are regulated in part by altering accumulation and sensitivity to the plant hormones abscisic acid (ABA):gibberellin (GA). ABA induced dormancy, while GA is involved in dormancy breaking. This paper reviews studies of these hormone signaling pathways as well as other dormancy regulating genes detected by molecular studies using microarray, genetics, and protein biochemistry.
Technical Abstract: Seed dormancy provides a mechanism for plants to delay germination until conditions are optimal for survival of the next generation. Dormancy release is regulated by a combination of environmental and endogenous signals with both synergistic and competing effects. Molecular studies of dormancy have compared transcriptomes, proteomes, and hormone levels in dormancy states ranging from deep primary or secondary dormancy to varying degrees of release. The balance of ABA:GA levels and sensitivity is a major, but not sole, regulator of dormancy status. ABA promotes dormancy induction and maintenance while GA promotes progression from release through germination; levels are regulated by the balance of synthesis and catabolism. Mediators of environmental and hormonal response include both positive and negative regulators, many of which are feedback regulated to enhance or attenuate the response. The net result is a slightly heterogeneous response, thereby providing more temporal options for successful germination.