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Research Abstracts Online
January - December 2011

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University of Minnesota Twin Cities
College of Food, Agricultural, and Natural Resource Sciences
Department of Horticultural Science

PI: Alan G. Smith

RNA-seq for Gene Discovery in Pollen-Pistil Interactions

The goal of this project is to identify genes important to pollen tube growth and interspecific reproductive barriers. Plants exhibit complex reproductive relationships that prevent hybridization and are necessary for speciation. Pre- and post-zygotic reproductive barriers can act in combination to reduce or eliminate gene flow among related species, but prezygotic barriers act first after pollination and occur between the pollen tube and the transmitting tract of the style. The highly differentiated transmitting tract evolved with the enclosed ovules of angiosperms and is the pathway for pollen tube growth from the stigma to the ovules. It is thought to provide nutrition, guidance, and signaling during pollen tube growth. Genetic ablation of the Nicotiana tabacum transmitting tract resulted in the production of a hollow style, lacking mature transmitting tract tissue. The hollow style supports compatible (N. tabacum) pollen tube growth and surprisingly, eliminated the interspecific incompatibility to N. obtusifolia pollination. Normally, N. tabacum styles are sexually incompatible with N. obtusifolia pollinations, resulting in failure of the pollen tubes to reach the ovules prior to floral senescence. However, in the transmitting tract ablated lines, N. obtusifolia pollen tubes grow to and fertilize N. tabacum ovules.

Group Members

Neil Anderson, Faculty Collaborator
Ben Clasen, Research Associate
Carrie Eberle, Graduate Student
Adrian Hegemen, Faculty Collaborator