Analysis of Cold Hardiness, Dehydrins, and Their Gene Expressions during Cold Acclimation and Deacclimation in Four Peach Cultivars (Prunus persica)

Changes in cold hardiness, dehydrins and their gene expressions were monitored in the shoots of four peach cultivars (Daewol, Aikawanakajima, Fukuyokabijin, and Kiraranokiwami). Cold hardiness of all the cultivars, determined by electrolyte leakage analysis, gradually increased during the autumn, reached a maximum in midwinter, and then decreased by April. The SDS-PAGE profiles of proteins from four cultivars were very similar during investigated period. Data indicate that a 60 kDa protein encoded by PpDhn1 (Prunus persica dehydrin) gene of four cultivars accumulated to high level during fall and winter (from November 2011 to January 2012) followed by a complete disappearance in spring (from March to April 2012). A 30 kDa of polypeptide, assumed to be a dehydrin protein encoded by PpDhn2 gene, did not display discernible changes. A 16 kDa of polypeptide characterized as a “bark-storage protein” also exhibited a similar seasonal pattern in all cultivars. Changes of dehydrin gene expressions by a quantitative real-time RT-PCR were performed to find out the relationship with cold hardiness. Expression patterns of PpDhn1 and PpDhn3 genes paralleled fluctuations in cold hardiness. The PpDhn2 gene did not appear to be seasonally regulated.