Department of Environmental Horticulture, Clemson University, Clemson, SC, USA.
Plant Mol Biol. 2010 May;73(1-2):157-67. doi: 10.1007/s11103-010-9608-5. Epub 2010 Feb 9.
We previously identified a cluster of d ormancy-a ssociated M ADS-box transcription factors (DAM genes) in peach [Prunus persica (L.) Batsch] as potential candidates for control of the non-dormant phenotype observed in the evg mutant. Of these genes, DAM3, DAM5 and DAM6 were winter expressed, suggesting a role for these genes during endodormancy. We used peach cultivars with contrasting chilling requirements (CR) for bud break to observe the expression of DAM3, DAM5 and DAM6 in response to chilling accumulation in the field and controlled environments. Vegetative terminal and floral buds were sampled weekly from field grown 'Contender' (1050 h CR), 'Rubyprince' (850 h CR) and 'Springprince' (650 h CR) peach cultivars through winter 2008-2009. Flower and vegetative terminal bud break potential was evaluated at each sampling by forcing cuttings in a growth-permissive environment. We also measured vegetative terminal bud break and DAM gene expression in potted 'Contender' and 'Peen-To' (450 h CR) trees under controlled-environment cold exposure. DAM3, DAM5 and DAM6 are all suppressed by exposure to chilling temperatures in the field and in controlled conditions. Expression of DAM5 and DAM6 are higher in high chill cultivars prior to chilling accumulation and their expression level reaches a minimum in each cultivar coincident with acquisition of bud break competence. Expression levels of DAM5 and DAM6 in vegetative tips in controlled environment conditions were negatively correlated with the time required for bud break in forcing conditions. The expression patterns of DAM5 and DAM6 are consistent with a role as quantitative repressors of bud break.
我们之前在桃[Prunus persica (L.) Batsch]中鉴定了一组与休眠相关的 MADS-box 转录因子（DAM 基因），它们可能是控制 evg 突变体中观察到的非休眠表型的候选基因。在这些基因中，DAM3、DAM5 和 DAM6 是冬季表达的，这表明这些基因在终休眠期间发挥作用。我们使用具有不同休眠需求（CR）的桃品种来观察 DAM3、DAM5 和 DAM6 在田间和控制环境中对冷积累的响应。从 2008 年至 2009 年冬季，每周从田间生长的 'Contender'（1050 h CR）、'Rubyprince'（850 h CR）和 'Springprince'（650 h CR）桃品种中采集营养末端和花芽。通过在生长允许的环境中强制扦插来评估每个采样点的花和营养末端芽的打破潜力。我们还在受控环境冷暴露下测量了盆栽 'Contender'和 'Peen-To'（450 h CR）树的营养末端芽打破和 DAM 基因表达。DAM3、DAM5 和 DAM6 都受到田间和控制条件下冷温的抑制。在冷积累之前，高冷品种中的 DAM5 和 DAM6 表达较高，并且它们的表达水平在每个品种中达到最低，与芽打破能力的获得一致。在受控环境条件下，营养尖端的 DAM5 和 DAM6 表达水平与强制条件下打破芽所需的时间呈负相关。DAM5 和 DAM6 的表达模式与作为芽打破的定量抑制剂的作用一致。
