Kelley, Dior , Gasser, Charles .
Polarity Determinants in Arabidopsis Ovule Development.
In spermatophytes, ovules are critical female reproductive structures that develop into seeds. Angiosperm ovules include one, or more commonly two, integuments that cover the nucellus and female gametophyte. Recent genetic studies in Arabidopsis have shown that mutations in putative polarity determinants result in amorphous or arrested integument growth, suggesting that such determinants play key roles in ovule development. ABERRANT TESTA SHAPE (ATS) is a member of the KANADI (KAN) gene family that is necessary for laminar extension of the inner integument and for maintaining integument separation. Loss of function of KAN1 and KAN2 results in an amorphous outer integument and a normal inner integument, implying that these polarity determinants are necessary for laminar extension of the outer integument. Dominant mutations in PHABULOSA and PHAVOLUTA also negatively affect integument formation, suggesting that such Class III Homeodomain-Leucine Zipper (Class III HD-ZIP) transcription factors may also be important for integument growth. Based on current knowledge regarding the expression and regulation of polarity genes during leaf morphogenesis we propose a model to explain integument initiation and extension. Expression analyses and transgenic studies of KAN and Class III HD-ZIP transcription factors are being combined with genetic analysis to further define the role of polarity establishment in integument growth.
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1 - University of California, Davis, Section of MCB, One Shields Ave, Davis, CA, 95616, USA
2 - University of California, Davis, Section of MCB
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM