Evolutionary Developmental Biology (Evo-Devo)
Krosnick, Shawn , Gasser, Charles , Potter, Daniel .
What is a nectary? First insights into homology assessment in Passiflora using CRABS CLAW.
Passiflora is a diverse genus consisting of more than 520 species of vines, lianas and small trees. The group displays remarkable variation in floral and vegetative features, even among closely related species. A key characteristic of the genus is the presence of complex nectaries throughout the plant. These nectaries encourage pollination, deter herbivores, and attract bodyguards. Floral and extrafloral nectaries are present on all species of Passiflora within flowers, on floral bracts, stipules, petioles, on leaf margins, and abaxial leaf surfaces. In Passiflora, the position, shape, size, and arrangement of nectaries is so variable that homology assessment among the different nectary classes is difficult. As nectaries likely represent a key morphological innovation for the genus, the need for clear statements of homology among the different nectary classes is great. CRABS CLAW (CRC) has been identified as a key component in the regulation of nectary expression in the core eudicots, and thus represents a strong candidate gene for use in examining the homology among the nectaries of Passiflora. While CRC is not the only gene involved in regulation of nectary expression, it is an integral component and should thus be under strong functional selection within the nectaries of Passiflora. Preliminary data indicate that CRC is present in Passifloraas a single copy, similar to other angiosperms. RT-PCR analysis demonstrated CRC expression in the nectaries of Passiflora. Semi-quantitative RT-PCR analyses were also performed to provide an indication of the overall levels of CRC across floral and vegetative tissues during all stages of development. These data suggest that CRC will be useful in homology assessment among the different nectary classes, thus allowing the opportunity to examine evolution of nectaries across Passiflora.
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1 - University of California, Davis, Plant Sciences, One Shields Avenue, Mail Stop 2, Davis, CA, 95616, USA
2 - University of California, Davis, Section of Molecular and Cellular Biology, One Shields Avenue, Davis, CA, 95616, USA
Presentation Type: Oral Paper:Papers for Topics
Location: Astoria Room/Hilton
Date: Wednesday, July 11th, 2007
Time: 11:30 AM