Host Specificity of a Rare Parasitic Plant, Cuscuta harperi
Abstract (300 words maximum)
Cuscuta harperi (Harper’s Dodder) is a rare parasitic vine lacking roots and leaves that is endemic to hot, dry sandstone and granite outcrop habitats. Cuscuta species find its appropriate host plants by following gradients of specific volatile organic compounds in the air emitted by other plants and growing towards appropriate hosts or away from unsuitable species. Geographically separated populations of C. harperi exhibit drastically different host usage from each other, and we aim to determine whether differences in host specificity between populations are due to genetic differences related to responses to volatile chemicals or if observed host use is determined by plastic responses to extrinsic factors. To test for differences in host volatile chemical response between the populations, we will allow seedlings from two populations exhibiting drastically different host use to choose between two potential hosts: (Liatris microcephala (Small-headed Blazing Star) and Bigelowia nuttallii (Nuttall’s Rayless Goldenrod)) under identical greenhouse conditions. A population on an outcrop of Altamaha Grit in the coastal plain of Georgia, that specializes exclusively on Bigelowia nuttallii will be compared to a sandstone outcrop population in northern Alabama where individuals grow on a wide range of hosts, including both Liatris microcephala and Bigelowia nuttallii.
Academic department under which the project should be listed
CSM - Ecology, Evolution, and Organismal Biology
Primary Investigator (PI) Name
Joel McNeal
Host Specificity of a Rare Parasitic Plant, Cuscuta harperi
Cuscuta harperi (Harper’s Dodder) is a rare parasitic vine lacking roots and leaves that is endemic to hot, dry sandstone and granite outcrop habitats. Cuscuta species find its appropriate host plants by following gradients of specific volatile organic compounds in the air emitted by other plants and growing towards appropriate hosts or away from unsuitable species. Geographically separated populations of C. harperi exhibit drastically different host usage from each other, and we aim to determine whether differences in host specificity between populations are due to genetic differences related to responses to volatile chemicals or if observed host use is determined by plastic responses to extrinsic factors. To test for differences in host volatile chemical response between the populations, we will allow seedlings from two populations exhibiting drastically different host use to choose between two potential hosts: (Liatris microcephala (Small-headed Blazing Star) and Bigelowia nuttallii (Nuttall’s Rayless Goldenrod)) under identical greenhouse conditions. A population on an outcrop of Altamaha Grit in the coastal plain of Georgia, that specializes exclusively on Bigelowia nuttallii will be compared to a sandstone outcrop population in northern Alabama where individuals grow on a wide range of hosts, including both Liatris microcephala and Bigelowia nuttallii.