From “Parasitic Plants Steal Genes from Their Hosts”
ScienceDaily, June 8, 2012), we learn,
New research published June 8 in BioMed Central’s open access journal BMC Genomics reveals that the Malaysian parasitic plant Rafflesia cantleyi, with its 50cm diameter flowers, has ‘stolen’ genes from its host Tetrastigma rafflesiae. Analysis of these genes shows that their functions range from respiration to metabolism, and that some of them have even replaced the parasites own gene activity.
Rafflesia cantleyi is an obligate holoparasite (dependent on its host, and only that host, for sustenance), which grows on Tetrastigma rafflesiae, a member of the grape family. Researchers from Singapore, Malaysia and USA collaborated to systematically investigate the possibility of horizontal gene transfer between these two plants. By looking at the transcriptome (the transcribed products of switched on genes) they found 49 genes transcribed by the parasite, accounting for 2% of their total transcriptome, which originally belonged to the host. Three quarters of these transcripts appear to have replaced the parasites own version.
Most of these genes had been integrated into the parasite’s nucleus, allowing the researchers to perform genomic analysis.
Parasites have an interest in preserving their hosts as a food source (one they don’t recognize, of course). It would be interesting to know if the gene transfer doesn’t harm the host but binds the two life forms closer together – or even, in some cases, makes the parasite necessary to the host.
See also: Horizontal gene transfer: Gene from bacteria lets beetle feed only on coffee beans