Submitted to: Journal of Aquatic Plant Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/20/2003
Publication Date: 1/20/2004
Citation: Madeira, P.T., Van, T.K., Center, T.D. 2004. An improved molecular tool for distinguishing monecieous and dioecious hydrilla. Journal of Aquatic Plant Management. 42:28-31. Interpretive Summary: Two types of hydrilla, an invasive aquatic weed, are known to occur in the United States. One type (dioecious), possessing only female flowers, is common in the southeast. The second type (monoecious), which possesses both male and female flowers on the same plant, occurs mainly in the central Atlantic and northeastern states. As the ranges of each type have expanded they have begun to overlap. Management techniques can differ for the types so ecosystem managers need tools to distinguish them. We have sequenced individuals of the two types from around the United States and describe 3 differences which distinguish them. We also describe a simple biological (PCR) reaction which distinguishes the types by producing a product only for the monoecious type.
Technical Abstract: Two biotypes of Hydrilla verticillata occur in the United States, a dioecious type centered in the southeast and a monoecious type in the central Atlantic and northeastern states. Ecosystem managers need tools to distinguish the types as the ranges of each type expand and begin to overlap. A molecular tool using RAPDs is available but its use is limited by a need for reference samples. We describe an alternative molecular tool which uses 'universal primers' to sequence the trnL intron and trnL-F intergenic spacer of the chloroplast genome. This sequence yields three differences between the biotypes (two gaps and one single nucleotide polymorphism). A primer has been designed which ends in a gap that shows up only in the dioecious plant. PCR using this primer produces a product for the monoecious but not the dioecious plant.