A novel zinc-finger protein with a proline-rich domain mediates ABA-regulated seed dormancy in Arabidopsis
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- He, Y. & Gan, S. Plant Mol Biol (2004) 54: 1. doi:10.1023/B:PLAN.0000028730.10834.e3
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Seed dormancy is an important developmental process that prevents pre-harvest sprouting in many grains and other seeds. Abscisic acid (ABA), a plant hormone, plays a crucial role in regulating dormancy but the underlying molecular regulatory mechanisms are not fully understood. An Arabidopsis zinc-finger gene, MEDIATOR OF ABA-REGULATED DORMANCY 1(MARD1) was identified and functionally analyzed. MARD1expression is up-regulated by ABA. A T-DNA insertion in the promoter region downstream of two ABA-responsive elements (ABREs) renders MARD1unable to respond to ABA. The mard1 seeds are less dormant and germinate in total darkness; their germination is resistant to external ABA at the stage of radicle protrusion. These results suggest that this novel zinc-finger protein with a proline-rich N-terminus is an important downstream component of the ABA signaling pathway that mediates ABA-regulated seed dormancy in Arabidopsis.