|Farrell JR., Robert E - PENN STATE UNIV|
|Norelli, John (jay)|
Submitted to: Journal of the American Society for Horticultural Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 6, 2006
Publication Date: July 21, 2006
Citation: Bassett, C.L., Wisniewski, M.E., Farrell Jr., R., Artlip, T.S., Norelli, J.L. 2006. Global analysis of genes regulated by low temperature and photoperiod in peach bark. Journal of the American Society for Horticultural Science 131:551-563. Interpretive Summary: Crop losses in the U.S. due to cold temperature extremes can be substantial. This is especially true of fruit trees which not only have to survive late frosts, but also have to live through periodic harsh winters, particularly in temperate zones. One of the problems hampering our ability to develop trees with better cold tolerance is a lack of understanding of how genes defending trees from cold stresses are regulated. The present study describes the application of a new methodology for the global identification and analysis of genes associated with defending peach trees from cold extremes. The results revealed new genes which are up-regulated by cold, sets of genes which respond more to daylength than cold exposure, and sets of genes which are suppressed by cold temperature. The results have identified novel genes which can be used to develop trees with better tolerance for cold winter extremes.
Technical Abstract: Living cells respond to environmental signals by up-regulating specific subsets of genes while down-regulating others. Global approaches to identifying these different groups of genes have been successfully applied to several plant systems. Limitations commonly associated with several types of global approaches can be overcome by a combination of PCR-select subtractive hybridization of cDNAs from different treatments. By varying which cDNA serves as the driver (in excess in the hybridization reaction) and which cDNA serves as the testor, one can obtain both up-regulated (forward subtraction hybridization) and down-regulated (reverse subtraction hybridization) sequences in response to a given condition or treatment. To profile gene expression at different temperatures under different photoperiods, we have created PCR-select subtracted libraries from peach (Prunus persica [L.] Batsch.) bark tissues sampled from trees kept at 5ºC and 25ºC under short day (SD) photoperiod or exposed to a night break (NB) interruption during the dark period of the SD cycle. Sequences expressed in forward and reverse subtractions using various subtracted combinations of temperature and photoperiod treatments were cloned, sequenced, and identified by BLAST and CLUSTALW analysis. Genes unique to each treatment and genes that overlap between two or more treatments are presented.