ISHS Acta Horticulturae 626: XXVI International Horticultural Congress: Berry Crop Breeding, Production and Utilization for a New Century
ENHANCEMENT OF FREEZING TOLERANCE OF STRAWBERRY BY HETEROLOGOUS EXPRESSION OF CBF1 |
| Authors: | C.L. Owens, A.F. Iezzoni, J.F. Hancock |
| Keywords: | cold acclimation, Rosaceae |
| Abstract:
Many rosaceous fruit crops suffer yield reductions due to early season freezes during or just prior to bloom. Fruit cultivars with improved floral freezing tolerance would be one approach to alleviate this problem. In model plant systems, researchers have been able to identify genes that play a role in freezing tolerance by identifying proteins regulated in response to cold temperature. Even though freezing tolerance is a complexly inherited trait, manipulation of just one gene, CBF1, a cold-induced transcription factor important in the cold acclimation response, has been shown to improve the whole plant freezing tolerance of Arabidopsis. In order to help determine if the CBF1 and the CBF1 regulon are conserved in the Rosaceae, the effect of CBF1 over-expression on strawberry freezing tolerance was determined. Agrobacterium-mediated transformation of a CaMV35S-CBF1 construct was conducted on Fragaria x ananassa 'Honeoye' crown discs. Two transgenic lines were regenerated that expressed the transgene at low levels in both leaves and receptacles with pistils. Receptacles with attached pistils of the transgenic lines showed no significant change in freezing tolerance when compared to wild type plants. However, the temperature at which 50 % electrolyte leakage occurred in detached leaf-discs from the two transgenic lines was -8.2° C and -10.3° C, respectively. These freezing tolerance values were significantly greater than the value for the wild-type 'Honeoye' leaf discs of -6.4° C | |
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