THE PLANT CELL, Vol 7, Issue 11 1899-1911, Copyright © 1995 by American Society of Plant Biologists
Fate of Parasite and Host Organelle DNA during Cellular Transformation of Red Algae by Their Parasites
L. J. Goff and A. W. Coleman
Department of Biology, University of California, Santa Cruz, California 95064
The transfer of a nucleus into a cytoplasm of a genetically foreign cell
and its subsequent multiplication in the cytoplasm of this cell
characterize most parasitic red algal species and their interactions with
specific red algal hosts. Nuclei enter the host's cytoplasm upon cell
fusion of parasite and host cell; here, they replicate, are spread to
contiguous host cells, and ultimately are packaged into spores that
reinfect other host thalli. In this study, we examined whether the
proplastids and mitochondria that occur in these red algal adelphoparasites
are acquired from their host or whether they are unique to the parasite and
are brought into the host along with the parasite nucleus. To establish
their origins and fates, plastid and mitochondrial restriction fragment
length polymorphisms (RFLPs) of parasite cells were compared with those of
their host plastid and mitochondrial DNA in three host and parasite pairs.
For plastids, no RFLP differences were found between hosts and parasites,
supporting an earlier conclusion, based on microscopic studies, that the
proplastids of parasites are acquired from their hosts. For mitochondria,
characteristic RFLP differences were detected between host and parasite for
two of the pairs of species but not for the third. Evidence of the
evolutionary difference between hosts and their parasites was shown by RFLP
differences between nuclear ribosomal repeat regions.
