The Parasitic Plant Genome Project (PPGP)

Parasitic plants provide a unique opportunity to understand how genomes evolve in response to the change from autotrophic to heterotrophic lifestyles. The overall goal of the Parasitic Plant Genome Project (PPGP) funded by the National Science Foundation is to carry out the comparative functional genomic analysis of parasitic plants in order to discover the genome-wide changes that led to the establishment of the parasitic lifestyle and the resulting evolutionary consequences of adoption of the parasitic life-style. At the present time we are generating developmental stage-specific cDNAs from transcripts isolated from Triphysaria versicolor, Striga hermonthica and Striga asiatica, and Orobanche ramosa. These plant species are evolutionarily related yet span the range of parasitic ability from completely host-dependent holoparasites to free-living facultative parasites. Mimulus is an autotrophic, non-parasitic plant that is closely related to the Orobanchaceae.

The phylogenetic relationships of parasitic plants in the family Orobanchaceae and the closely related
nonparasitic species Mimulus (above).

We will use various sequencing strategies (Sanger, 454, Solexa) to obtain ESTs from each parasite species. The encoded genetic information captured as ESTs will be subjected to a rigorous bioinformatics analysis. We plan to determine the extent of gene diversity, generate phylogenetic trees of the encoded genes, and analyze the captured gene data in order to gain insight into possible genetic changes that occurred in the origin of parasitism and generation of an increasingly host-dependent parasitic lifestyle. Of particular interest are those elements of gene content and regulation that are shared or unique among the parasites.

Links to collaborating laboratories are given below.

Jim Westwood at Virginia Tech

John Yoder at University of California, Davis

Claude dePamphilis at Penn State

Visit the Parasitic Plant Genome Project (PPGP) Website

Read about our work