LOPEZ-BAUTISTA, J. M.1* and R. L. CHAPMAN2. 1Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504-2451 U.S.A.; 2Department of Biological Sciences, Louisiana State University, Baton Rouge, LA 70803-1705 U.S.A.. - Phragmoplastins, the Trentepohliales, and the evolution of the cytokinesis in green plants.
Green plants have been shown to have a common ancestor and to contain
two lineages: the Chlorophytes and the Streptophytes, both
encompassing representatives of the original "green algae."
The phragmoplast-mediated cell division characterizes the land plants
in the Streptophyte lineage and some basal green algal orders
(Coleochaetales, Charales and Zygnematales). However, a well-developed
phragmoplast-type cell division has been documented in two subaerial
green algae (Cephaleuros parasiticus and Trentepohlia
odorata) belonging to the order Trentepohliales, an order that
molecular sequence data place unequivocally within the Chlorophytes
(rather than Streptophytes). Is the phragmoplast-mediated cell
division of the Trentepohliales a case for homology or non-homology?
In order to reveal the answer to this question, we are exploring the
potential phylogenetic information inferred from gene sequences of
phragmoplastin, a dynamin-like protein which has been demonstrated to
be associated with cell plate formation during the
phragmoplast-mediated cytokinesis in land plants. Primers were
designed based on an available phragmoplastin sequence from soybean,
and yielded PCR amplifications from the green algae
(Trentepohlia and Cephaleuros), a bryophyte
(Bazzania) and land plants (Glycine and
Arabidopsis). The evolutionary history of the development of
the phragmoplast may remain in the analysis of the gene sequences for
this group of proteins.
Key words: Cytokinesis, Evolution, Green Plants, Phragmoplast, Phragmoplastin, Trentepohliales