Researchers at Penn State University found that some parasitic weeds are able to take genes from their host plants and use it against them in a process known as horizontal gene transfer.
Horizontal gene transfer isn't a new concept for scientists: it's been observed in simple life forms such as bacteria. Most evolution in complex organisms comes with reproduction, but due to the parasitic plant's close relationship with the host, there is a high likelihood of genes traveling from the host to the parasite's genome.
The team was able to document 52 incidences of gene transfer in the parasitic broomrape family. By studying mRNA (messenger RNA), the researchers found DNA sequences foreign to the parasite, found from genes in past host plants. The parasite's roots contact and enter the host plant as it always does, extracting water, sugar, nutrients and nucleic acid - including the host plant's DNA and RNA.
The researchers suggested that the DNA is then used to boost the parasite's ability to invade hosts, to overcome the defenses of the host, and to reduce the risk of infection for the parasite.
Egyptian broomrape, one of the plants studied, was found in North America for the first time in July 2014. It attacks field crops and some ornamentals including asters and chrysanthemums. Yellowbeak owl's-clover is a semiparasitic member of the broomrape family that can live independently, but, if given the chance, will latch on to ornamental and agricultural plants in the lupine family. It is native to the West Coast, found from California to British Columbia.