Fagopyrum Chloroplast Genome: Construction of Physical Maps and Characterization of Unique Sequence

We have constructed physical maps for the chloroplast genomes of buckwheat (F. esculentum) and related species (F. tataricum and F. cymosum) by using six restriction enzymes. A comparison of physical maps revealed 11 altered restriction site out of 259 analyzed. Phylogenetically, the chloroplast DNA of F. esculentum is quite distant from those of F. tataricum and F. cymosum. These results also suggest that the allogamous mode could be the ancestral reproductive system for Fagopyrum, whose present-day species display three different mechanisms of reproduction: allogamous, autogamous and vegetative, because both the distantly related species, F. esculentum and F. cymosum, maintain self-incompatibility due to hetero-styly. We also observed fragments Sma-8 5.05 kbp, which extend the inverted repeats in buckwheat species, exhibit little homology with tobacco chloroplast DNA clone. Comparison of the Sma-8 sequence and corresponding tobacco chloroplast DNA showed that an inversion occurred ranging 3.6 kbp from the end of inverted repeats to small single copy region in buckwheat chloroplast genome