Eberle, Carrie , Gardner, Nicole , Smith, Alan .
The Role of the Transmitting Tract in Pollination and Interspecific Incompatibility in Nicotiana .
Reproductive barriers among plant species can regulate gene flow, fitness and seed set. Interspecific incompatibility prevents fertilization and therefore gene flow among species and may be involved in the genesis of distinct species. The goal of this project is to test the role of the transmitting tract (TT) in reproductive biology and interspecific incompatibility in Nicotiana . Previous research suggests that the TT provides essential nutrition and direction for pollen tube growth. The TT of N. tabacum was ablated by expressing an RNase using a transmitting tract-specific promoter. Self-pollination of ablated lines of N. tabacum showed that pollen tubes grow in styles without a TT, which implies it is not essential for fertilization. To test the role of the TT in interspecific incompatibility, pollen tube growth was measured after N. tabacum pistils were pollinated by several Nicotiana species. Pollinations with incompatible-species pollen showed inhibited pollen tube growth in normal styles. However, pollination of flowers with an ablated TT either maintained an incompatible reaction or became compatible (no inhibition) depending on the species used as a pollen donor. Conversion of incompatible to compatible interactions suggests that the TT is essential to interspecific incompatibility. However, maintaining an incompatible interaction in the absence of the TT implies factors in other tissues control the interspecific incompatibility reaction among some species. These data show that the TT is not essential to pollen tube growth or fertilization, however it is essential for interspecific incompatibility of some pollen donors. Future research is directed at the role of the TT and other pistil tissues in gene flow and speciation.
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1 - University of Minnesota, Horticulutral Science, 1970 Folwell Ave, St Paul, MN, 55108, United States
2 - University of Minnesota, Horticulutral Science
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM