title: The regulatory role of vernalization in the expression of low-temperature-induced genes in wheat and rye.
abstract: Low temperature is one of the primary stresses limiting the growth and productivity of wheat (Triticum aestivum L.) and rye (Secale cereale L.). Winter cereals low-temperature-acclimate when exposed to temperatures colder than 10°C. However, they gradually lose their ability to tolerate below-freezing temperatures when they are maintained for long periods of time in the optimum range for low-temperature acclimation. The overwinter decline in low-temperature response has been attributed to an inability of cereals to maintain low-temperature-tolerance genes in an up-regulated state once vernalization saturation has been achieved. In the present study, the low-temperature-induced Wcs120 gene family was used to investigate the relationship between low-temperature gene expression and vernalization response at the molecular level in wheat and rye. The level and duration of gene expression determined the degree of low-temperature tolerance, and the vernalization genes were identified as the key factor responsible for the duration of expression of low-temperature-induced genes. Spring-habit cultivars that did not have a vernalization response were unable to maintain low-temperature-induced genes in an up-regulated condition when exposed to 4°C. Consequently, they were unable to achieve the same levels of low-temperature tolerance as winter-habit cultivars. A close association between the point of vernalization saturation and the start of a decline in the Wcs120 gene-family mRNA level and protein accumulation in plants maintained at 4°C indicated that vernalization genes have a regulatory influence over low-temperature gene expression in winter cereals.
authors.affiliation: Crop Development Centre, University of Saskatchewan, 51 Campus Drive, S7N 5A8, Saskatoon, SK, Canada.
authors.forename: D B
authors.initials: DB
authors.lastname: Fowler
authors.forename: L P
authors.initials: LP
authors.lastname: Chauvin
authors.forename: A E
authors.initials: AE
authors.lastname: Limin
authors.forename: F
authors.initials: F
authors.lastname: Sarhan