Adamczyk, Benjamin J. , Fernandez, Donna E. .
Three MIKC*-type MADS-box genes redundantly regulate pollen function in Arabidopsis.
Genetics and expression analyses were used to investigate the function of the six MIKC*-type MADS domain transcription factors in Arabidopsis. MIKC* factors are ancient in origin and structurally conserved across a wide range of plant taxa. Previous studies have shown that the Arabidopsis MIKC* genes are expressed in pollen and embryonic tissue. We isolated loss-of-function alleles for five Arabidopsis MIKC* members, and analyzed mutants for changes in embryo and pollen development. Plants containing mutations in three MIKC* genes on chromosome I (AGL65, AGL66, and AGL104) exhibited reduced fertility relative to wild type or double mutant plants. Reciprocal crosses confirmed that these MIKC* factors play a redundant gametophyte-specific regulatory role in pollen. In the presence of these mutant alleles, AGL94, another MIKC* gene is up-regulated, and AGL18, a pollen-expressed MIKCc MADS-box gene, is down-regulated. A quadruple mutant (agl65/66/94/104) displayed transmission rates closer to wild type, suggesting that the up-regulation of AGL94 may compromise pollen function. We are currently investigating other factors that may be involved in a MADS-based regulatory network in pollen, as well as further characterizing higher-order mutants using electron microscopy, and in vitro and in vivo pollen germination assays. Supported by USDA NRICGP (2001-35304-10887), and the UW-Madison Graduate School.
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1 - University of Wisconsin-Madison, Botany, 430 Lincoln Dr., Birge Hall Rm. B201, Madison, WI, 53706, USA
2 - University of Wisconsin-Madison, Botany
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM