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After the book - Progress in parasitic plant research since Kuijt's Biology of Parasitic Flowering Plants (1969)

McNeal, Joel R. [1], Boore, Jeffrey L. [2], Kuehl, Jennifer [2], dePamphilis, Claude W. [1].

Evidence for photosynthetic potential across the parasitic plant genus Cuscuta using complete plastid genome sequences.

The genus Cuscuta (dodders) contains more than 150 species of epiphytic vines that are obligate parasites on the stems of a wide diversity of host plants, with a number of species commonly becoming agricultural pests. Although all or most Cuscuta species have long been considered to be nonphotosynthetic holoparasites, there is a wide range of chlorophyll content and thylakoid structure across the genus. Practically all species produce some chlorophyll at certain life-stages or in certain specific tissues, although leaves are reduced to minute scales in all species. For this study, we sequenced the entire plastid genomes of two distantly related species of Cuscuta that represent the opposite ends of the spectrum for chlorophyll content and plastid structure in the genus. Selected genes were also sequenced for various other Cuscuta species representing systematically intermediate lineages. In addition, the full plastid genome sequence of Ipomoea purpurea (Morning Glory) was sequenced as an outgroup and to determine which alterations to the plastid genome may have predated the evolution of parasitism. Results indicate that most species of Cuscuta probably are photosynthetic to a degree despite the fact that many lack genes and promoters for plastid-encoded polymerase. Patterns of selection, gene loss, and gene content, as well as the implications of photosynthesizing with a streamlined plastid genome, will be discussed in a phylogenetic context.


1 - Pennsylvania State University, Department of Biology, 208 Mueller Lab, University Park, Pennsylvania, 16802-5301, USA
2 - DOE Joint Genome Institute, Department of Evolutionary Genomics, 2800 Mitchell Drive, Walnut Creek, California, 94598, USA

Keywords:
Cuscuta
parasitic plants
plastid genome evolution
photosynthesis
Convolvulaceae.

Presentation Type: Symposium
Session: 4-6
Location: Ballroom 2 (Cliff Lodge)
Date: Monday, August 2nd, 2004
Time: 10:45 AM
Abstract ID:494


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