Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/2/2004
Publication Date: 3/12/2004
Citation: Yan, L., Loukoinov, A., Blechl, A.E., Tranquilli, G., Ramakrishna, W., Sanmiguel, P., Bennetzen, J.L., Echenique, V., Dubcovsky, J. 2004. The wheat vrn2 gene is a flowering repressor downregulated by vernalization. Science. 303: 1640-1644 Interpretive Summary: An important agronomic characteristic of winter wheat is the requirement for a growth period in cold temperatures to ensure that flowering is efficient and synchronized. This requirement is called vernalization and is controlled by two genes in wheat, Vrn1 and Vrn2. This paper reports the use of traditional genetics, molecular biology, and biotechnology to isolate and verify the identity of the DNA sequences that comprise the Vrn2 gene. By specifically suppressing the expression of this gene, the flowering time of winter wheat variety Jagger was accelerated by more than a month without any cold treatment. The protein encoded by the Vrn2 gene is of a type that controls the activity of other genes. The isolation of this gene and determination of its DNA sequence will allow the study of how flowering and subsequent grain production is controlled by temperature, photoperiod and other environmental conditions. The knowledge gained is applicable to wheat, barley and other temperate grass crops.
Technical Abstract: Plants with a winter growth habit flower earlier when exposed for several weeks to cold temperatures, a process called vernalization. We report here the positional cloning of wheat vernalization gene VRN2, a dominant repressor of flowering that is downregulated by vernalization. Loss of function of VRN2, whether by natural mutations or deletions, resulted in spring lines, which do not require vernalization to flower. Reduction of the RNA level of VRN2 by RNA interference accelerated flowering time of transgenic winter wheat plants more than a month.