Chinese scientists find large-scale gene loss in evolution of parasitic plants

KUNMING - Researchers with the Chinese Academy of Sciences have found large-scale gene losses in parasitic plants such as dodders, or Cuscuta australis.

Most plants absorb sunlight and CO2 through their leaves, taking in water and minerals from the soil through their roots. However, parasitic plants are a particular class of plants that extract water and nutrients from other plants, said Wu Jianqiang, who led the research in Kunming Institute of Botany, Chinese Academy of Sciences.

The origin and evolution of plant parasitism, as well as the specific physiology and ecology, are exciting fields and much remains to be studied, he said.

Dodders are globally distributed holoparasites and have no roots or leaves. In recent years, dodders have become a valuable model for studying parasitic plants.

Wu's team spent a year and a half to map out the genome of the dodder Cuscuta australis.

"We found the Cuscuta and Ipomoea had a common ancestor about 33 million years ago. The Cuscuta genome then rapidly evolved, and many genes were lost during evolution," he said.

Researchers found that about 11.7 percent of well-conserved genes in autotrophic plants do not exist in the C. australis genome, and many of the missing genes are essential for photosynthesis, functions of root and leaves, resistance to environmental stresses, and regulation of transcription.

"Interestingly, several genes critical for flowering time control are also missing. Gene loss is correlated with the major body changes in the dodder," he said.

This study was published in Nature Communications on Wednesday.