Y. Kishima et al., CHLOROPLAST DNA ANALYSIS IN BUCKWHEAT SPECIES - PHYLOGENETIC-RELATIONSHIPS, ORIGIN OF THE REPRODUCTIVE SYSTEMS AND EXTENDED INVERTED REPEATS, PLANT SCI, 108(2), 1995, pp. 173-179
We have constructed physical maps for the chloroplast genomes of buckw
heat (Fagopyrum esculentum) and related species (F. tataricum and F. c
ymosum) by using six restriction enzymes. The genome sizes were found
to be identical with approximately 155.5 kb. A comparison of physical
maps revealed 11 altered restriction sites out of 259 analyzed. Phylog
enetically, the chloroplast DNA of F. esculentum has been found to be
quite distant from those of F. tataricum and F. cymosum. These results
also suggest that the allogamous mode could be the ancestral reproduc
tive system for Fagopyrum, whose present-day species display three dif
ferent mechanisms of reproduction: allogamous, autogamous and vegetati
ve, because both the distantly related species, F. esculentum and F. c
ymosum, maintain self-incompatibility due to heterostyly. We also obse
rved that the unique 5.05-kb Sma-8 fragments, which extend the inverte
d repeats in buckwheat species, exhibit little homology with tobacco c
hloroplast DNA clones.