Responses to winter dormancy, temperature, and plant hormones share gene networks.

Gene networks modulated in winter dormancy (WD) in relation to temperature and hormone responses were analyzed in tea [Camellia sinensis (L.) O. Kuntze]. Analysis of subtracted cDNA libraries prepared using the RNA isolated from the apical bud and the associated two leaves (two and a bud, TAB) of actively growing (AG) and winter dormant plant showed the downregulation of genes involved in cell cycle/cell division and upregulation of stress-inducible genes including those encoding chaperons during WD. Low temperature (4°C) modulated gene expression in AG cut-shoots in similar fashion as observed in TAB during WD. In tissue harvested during WD, growth temperature (25°C) modulated gene expression in the similar way as observed during the period of active growth (PAG). Abscisic acid (ABA) and gibberellic acid (GA(3)) modulated expression of selected genes, depending upon if the tissue was harvested during PAG or WD. Tissue preparedness was critical for ABA- and GA(3)-mediated response, particularly for stress-responsive genes/chaperons. Data identified the common gene networks for winter dormancy, temperature, and plant hormone responses.