ISHS Acta Horticulturae 420: Ornamental Plant Improvement: Classical and Molecular
MOLECULAR MARKERS AND GENETIC TRANSFORMATION IN THE BREEDING OF ORNAMENTALS |
| Authors: | A. Vainstein, H. Ben-Meir, A. Zuker, A.A. Watad, G. Scovel, A. Ahroni, M. Ovadis |
| Abstract:
The applicability of DNA fingerprinting using mini- and microsatellite sequences to the identification of genotypes and the establishment of genetic distances between them was assessed for carnation and rose. The probability of two offspring from the crossing of similar genotypes having identical DNA fingerprints was found to be 1.8x10-6 for carnation and 2x10-8 for rose. A comparison of genetic relationships, not only within but also between categories, based on known genetic history, to genetic relationships deduced from DNA fingerprints, revealed a perfect match for both flower types. In carnation, rank correlation analyses of results yielded by each of three probes of different origin (two mini-and one microsatellite) revealed very good agreement between them. Hence it is apparent that DNA fingerprints of ornamentals can be used for both cultivar identification and to establish genetic relatedness and evolutionary kinship. Potential future applications of DNA fingerprints, such as the mapping and monitoring of loci controlling important horticultural traits, should also be of great assistance to ornamental breeding. Using the random amplified polymorphic DNA technique we identified a marker linked to 'bullheaded' flowers in carnation. The relationship between the amplified DNA fragment and the trait was observed in all fullsibs analyzed, as well as in halfsibs. This fragment was cloned and the applicability of the sequence-specific primers is currently being tested. In parallel we established a transformation procedure for carnation. The availability of methods to introduce a useful defined gene(s) would enable the specific alteration of a single trait and broaden the gene pool available for the crop. Transgenic carnation plants were produced by microprojectile bombardment of highly regenerative stem segments. Bombardment was performed with a plasmid carrying uidA and bar genes encoding  -glucuronidase and phosphinothricin-acetyltransferase, respectively.
Optimal transformation frequency was determined based on the transient expression of uidA in stem segments.
A two-step regeneration procedure based on the use of two different cytokinins was employed to enhance the production of viable adventitious shoots.
Presence of the bar gene in plants stably expressing uidA was confirmed by Southern blot analysis.
Since parameters for efficient transformation using the microprojectile bombardment approach can be precisely determined and hence easily reproduced, in contrast to, for example, Agrobacterium-mediated transformation, the introduction of specific genes into carnation could soon become less of an "art" and more of a routine procedure.
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