Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: RAPD DETECTION AND CHARACTERIZATION OF A DNA POLYMORPHISM
ASSOCIATED WITH DWARF BANANA SOMACLONAL VARIANTS
RAPD DETECTION AND CHARACTERIZATION OF A DNA POLYMORPHISM
ASSOCIATED WITH DWARF BANANA SOMACLONAL VARIANTS
Olivia P. Damasco 1, Ian D. Godwin 1, Robert J. Henry 2, Stephen
W. Adkins 1 and Mike K. Smith 3, 1 Department of Agriculture, and
2 Qld Agricultural Biotechnology Centre, The University of
Queensland, QLD 4072, 3 DPI Maroochy Horticultural Research
Centre, Nambour, QLD 4560, Australia.
Meristem culture is an ideal source of disease-free planting
material in vegetatively reproduced species such as banana. In
many instances however, somaclonal variation occurs, with
resultant plants having deleterious phenotypes, most frequent of
which is dwarfism. Dwarfs are rarely detected in vitro, and are
commonly not apparent until field planting has taken place. Our
experiments demonstrate that the dwarfs have a reduced
sensitivity to GA3. We have applied RAPD marker techniques to
assist with early detection of dwarfism. "Normal" and dwarf in
vitro plants of cv. New Guinea Cavendish were screened with 66
random decamer primers, of which 19 revealed polymorphisms.
These 19 primers were used to screen a range of known "normal"
and dwarf plants growing in vitro, in the glasshouse and the
field, all representing different somaclonal variation events.
In all, total genomic DNA of 80 plants of two cultivars was
analysed, including cv. New Guinea Cavendish (18 "normal", 21
dwarf) and cv. Williams (23 "normal", 18 dwarf). One primer,
OPJ-04 (Operon Tech., 5'-CCGAACACGG-3') consistently amplified a
band of approximately 1.5 kb in "normal" plants which was absent
in all dwarfs tested. This primer was then shown to consistently
amplify a band of similar size in "normal" chloroplast DNA which
was always absent in dwarf chloroplast DNA. This is preliminary
evidence that at least one component of this dwarf-ism may be
controlled by a highly mutable locus in the chloroplast genome.
Sequencing of the amplified fragment is in progress to
characterise the putative chloroplast DNA.
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