|Von Zitzewitz, J|
Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2006
Publication Date: 5/1/2006
Citation: Szucs, P., Karsai, I., Von Zitzewitz, J., Meszaros, K., Cooper, L., Gu, Y.Q., Chen, T., Hayes, P., Skinner, J. 2006. Positional relationship between photoperiod response qtl and photoreceptor and vernaliazation genes in barley. Theoretical and Applied Genetics. 112: 1,277-1,285. Interpretive Summary: Winterhardiness has three primary components:photoperiod (day length) sensitity, vernalization response, and low temperature tolerance. Photoperiod and vernalization regulate the vegetative to reproductive phase transition, and photoperiod regulates ecpression of key vernalization genes. In this report, we mapped six chromosomal regions that are responsible for photoperiod response of barley crop. Cloning and charaterization of these major photoperiod response genes will enhance our understanding of plant growth and development.
Technical Abstract: Barley winterhardiness consists of the regulatory input traits of photoperiod (day length) sensitivity and vernalization response and the physical trait of low temperature tolerance. Photoperiod and vernalization are adaptive and economically significant traits and photoperiod regulates expression of key vernalization genes. Using two barley mapping populations, we mapped six individual photoperiod response QTL effects and determined their positional relationship to the phytochrome and cryptochrome photoreceptor gene families and the key vernalization regulatory genes HvBM5A, ZCCT-H, and HvVRT-2. For the six photoreceptors (HvPhyA-C, HvCry1a/b, HvCry2), only HvPhyC coincided with a photoperiod response QTL position (chromosome 5HL) and is a candidate gene for this effect. Photoperiod and vernalization regulate the vegetative to reproductive phase transition, and we recently mapped the candidate genes for the 5HL VRN-H1 (HvBM5A) and 4HL VRN-H2 (ZCCT-H) loci. In this study, we mapped HvVRT-2, the barley TaVRT-2 ortholog (a wheat flowering repressor regulated by vernalization and photoperiod) to 7HS and determined that the map locations for each of these three vernalization genes coincides with small photoperiod QTL effects. HvBM5A and HvPhyC are closely linked on 5HL and therefore are currently both positional candidates for the same photoperiod effect. The positional relationship between all three vernalization regulatory genes and photoperiod QTL effects suggests vernalization gene pleiotropy could be occurring. While the HvPhyC and vernalization genes are positional photoperiod response QTL candidates, the functions of the HvPhyC, HvBM5A, ZCCT-H and HvVRT-2 genes relative to photoperiod response remain to be determined.