ARS | Publication request: A Transgenic approach to understanding cold tolerance in blueberry cultivars

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 13, 2009
Publication Date: January 15, 2009
Citation: Polashock, J.J., Rowland, L.J. 2009. A Transgenic approach to understanding cold tolerance in blueberry cultivars. Proceedings of the 2009 Atlantic Coast Agricultural Convention. Page 95.

Interpretive Summary: Cold and freezing injury reduces yield in blueberry due to damage to flower buds and other plant parts. The damage caused by freezing can also be an important entry point for stem diseases. Resistance to cold and freezing damage increases in the fall in preparation for winter temperatures. To better understand the process of increasing cold resistance in the fall, we isolated a gene that we believe helps regulate this process. We demonstrated that this gene does become very active in the fall in blueberry. We further confirmed the identity of the gene as regulator of this process by expressing it in the model plant Arabidopsis and demonstrating a positive effect on resistance to cold damage. This project will immediately benefit scientists studying cold resistance in blueberry and other woody perennials. The knowledge gained from this project will ultimately benefit breeders and finally the farmer through development of more cold hardy varieties .

Technical Abstract: Cold hardiness is an important trait in highbush blueberry. Cold hardiness is induced in the fall and helps prevent freezing damage to buds and other plant parts. Plant damage not only directly reduces yield potential, but provides ‘wounds’ that act as an entry point for some pathogens such as stem blight. Induction of cold hardiness, also known as acclimation, is accompanied by expression of a host of genes known as COR (cold responsive). A key regulator of COR genes is known to be CBF (C-repeat binding factor). An understanding of the key genes and their regulator(s) involved in cold hardiness will help predict cold hardiness levels in new potential cultivars and changes in hardiness in response to various horticultural practices. We isolated a putative CBF gene from blueberry and confirmed, using real time PCR that expression levels of this gene vary throughout the growing season and are highest in the fall. The gene was engineered for high level constitutive expression in the model plant Arabidopsis. The transgenic Arabidopsis expressing the blueberry gene were found to have increased cold tolerance. Analysis of COR gene expression levels showed that the blueberry gene product induced expression of at least two Arabidopsis COR genes.