In a new study in Current Biology, a team of researchers led by Professor Charles Davis presented the most complete genome yet assembled of one of the major Rafflesiaceae lineages, Sapria himalayana.
The genetic analysis revealed an astonishing degree of gene loss and surprising amounts of gene theft from its ancient and modern hosts. These findings bring unique perspectives into the number and kind of genes it takes to be an endoparasite (an organism that is completely dependent on its host for all nutrients), along with offering new insights into how far the genomes of flowering plants can be altered and still remain functional.
The analysis sheds light on a species of flowers who's evolutionary and genomic history is largely unknown because they lack a traditional body, spend most of their lives inside their hosts, and lack the machinery to perform photosynthesis (which keeps most plants alive).
At the same time, the data demonstrated an underlying evolutionary convergence to becoming a parasite because Sapria and the parasitic plants the researchers compared them to lost many of the same types of genes despite evolving separately.
"We concluded that there is a common genomic or genetic roadmap to how plant parasites evolve," said Cai Liming '20, Ph.D., a researcher at the University of California, Riverside, who helped lead the study as a graduate student in the Davis Lab while at the Harvard Graduate School of Arts and Sciences.
The research collaboration included scientists from across the country and around the world, including former students in the Davis lab and collaborators in Thailand and Malaysia. Harvard Gazette
Image: Sapria himalayana is found in Southeast Asia and its mottled red and white flower is about the size of a dinner plate. Courtesy of Charles Davis Lab