Lempe Janne, Peil Andreas, Flachowsky Henryk
Julius Kühn Institute (JKI) - Federal Research Centre for Cultivated Plants, Institute for Breeding Research on Fruit Crops, Dresden, Germany.
Front Plant Sci. 2022 Jan 17;12:803341. doi: 10.3389/fpls.2021.803341. eCollection 2021.
Winter dormancy - a period of low metabolic activity and no visible growth - appears as an adaptation to harsh winter conditions and can be divided into different phases. It is tightly controlled by environmental cues, with ambient temperature playing a major role. During endodormancy, a cultivar-specific amount of cold needs to be perceived, and during ecodormancy, heat hours accumulate before bud burst and anthesis in spring. Expression analysis, performed in several key fruit tree species, proved to be very useful in elucidating the molecular control of onset and release of dormancy. However, the time resolution of these experiments has been limited. Therefore, in this study, dense time-series expression analysis was conducted for 40 candidate genes involved in dormancy control, under the cool-temperate climate conditions in Dresden. Samples were taken from the cultivars 'Pinova' and 'Gala,' which differ in flowering time. The set of candidate genes included well-established dormancy genes such as genes, , and Furthermore, we tested genes from dormancy-associated pathways including the brassinosteroid, gibberellic acid, abscisic acid (ABA), cytokinin response, and respiratory stress pathways. The expression patterns of well-established dormancy genes were confirmed and could be associated with specific dormancy phases. In addition, less well-known transcription factors and genes of the ABA signaling pathway showed associations with dormancy progression. The three ABA signaling genes _, and showed a local minimum of gene expression in proximity of the endodormancy to ecodormancy transition. The number of sampling points allowed us to correlate expression values with temperature data, which revealed significant correlations of ambient temperature with the expression of the genes , , , and the . Interestingly, the slope of the linear correlation of temperature with the expression of differed between cultivars. Whether the strength of inducibility of expression by low temperature differs between the 'Pinova' and 'Gala' alleles needs to be tested further.
冬季休眠——一段代谢活动低且无明显生长的时期——似乎是对严酷冬季条件的一种适应，并且可分为不同阶段。它受到环境信号的严格控制，其中环境温度起主要作用。在深休眠期间，需要感知特定品种所需的低温量，而在生态休眠期间，热量小时数在春季芽萌发和开花前积累。在几种关键果树物种中进行的表达分析，在阐明休眠开始和解除的分子控制方面被证明非常有用。然而，这些实验的时间分辨率有限。因此，在本研究中，在德累斯顿的凉爽温带气候条件下，对40个参与休眠控制的候选基因进行了密集的时间序列表达分析。样本取自开花时间不同的‘皮诺娃’和‘嘎啦’品种。候选基因集包括成熟的休眠基因，如基因、、，此外，我们还测试了来自休眠相关途径的基因，包括油菜素类固醇、赤霉素、脱落酸（ABA）、细胞分裂素反应和呼吸应激途径。成熟休眠基因的表达模式得到了证实，并可与特定的休眠阶段相关联。此外，不太知名的转录因子和ABA信号通路的基因显示出与休眠进程的关联。三个ABA信号基因、和在内休眠向生态休眠转变附近显示出基因表达的局部最小值。采样点的数量使我们能够将表达值与温度数据相关联，这揭示了环境温度与基因、、和的表达之间存在显著相关性。有趣的是，温度与表达的线性相关性斜率在不同品种之间有所不同。‘皮诺娃’和‘嘎啦’等位基因之间低温诱导表达的强度是否不同需要进一步测试。
