Forest Health Research and Education Center, University of Kentucky, Lexington, KY 40546, USA.
Graduate School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, USA.
Tree Physiol. 2019 Jul 18;39(7):1136-1148. doi: 10.1093/treephys/tpz053.
Trees use many mechanisms to adapt and respond to stressful conditions. The phenylpropanoid pathway in particular is known to be associated with a diverse suite of plant stress responses. In this study, we explored the relationship between the phenylpropanoid pathway metabolite production, gene expression and adaptive trait variation associated with floral bud reactivation during and following dormancy in Prunus armeniaca L. (apricot). Concentrations of eight phenylpropanoid metabolites were measured during chill accumulation and at developmental stages corresponding to the emergence of sepals and petals in floral buds of varieties that differ phenotypically in bloom date (BD). A significant interaction effect of chill hours and BD phenotype on the concentration of each of the compounds was observed (mixed analysis of variance, P < 0.05), with the concentration of most phenylpropanoid metabolites dropping precipitously when sepals and petals emerged. While phenylpropanoid biosynthetic gene expression patterns were more variable in general, expression changed over time and was impacted, although to a lesser degree, by BD phenotype. Furthermore, separation of BD phenotypic groups was most pronounced when early and late BD varieties were at different developmental stages, i.e., 800 chill hours. Taken together, these results suggest that the phenylpropanoid pathway is associated with floral bud reactivation in apricot. Furthermore, we show that the phenylpropanoid pathway is also impacted by phenological trait variation associated with dormancy. A better understanding of how apricot and other perennial tree species respond and adapt to environmental perturbations will be critical for improvement programs aimed at identifying and breeding trees more suitable for rapidly changing environments.
树木利用多种机制来适应和应对胁迫条件。特别是苯丙烷途径，已知与植物多种应激反应有关。在这项研究中，我们探讨了李属（杏）休眠期间和休眠后花芽重新激活过程中与苯丙烷途径代谢产物产生、基因表达和适应性状变化相关的关系。在品种之间存在表型差异（开花日期 BD）的杏花芽中，测定了在冷积累期间和在花萼和花瓣出现时对应的发育阶段的八种苯丙烷代谢产物的浓度。观察到冷积累小时数和 BD 表型对每种化合物浓度的显著互作效应（混合方差分析，P<0.05），当花萼和花瓣出现时，大多数苯丙烷代谢产物的浓度急剧下降。虽然苯丙烷生物合成基因表达模式通常更具可变性，但表达随时间而变化，并且受到 BD 表型的影响，尽管程度较小。此外，当早花和晚花品种处于不同的发育阶段（即 800 个冷积累小时）时，BD 表型组的分离最为明显。总之，这些结果表明，苯丙烷途径与杏花芽重新激活有关。此外，我们表明，苯丙烷途径也受到与休眠相关的表型性状变化的影响。更好地了解杏和其他多年生树种如何响应和适应环境干扰，对于旨在识别和培育更适合快速变化环境的树木的改良计划至关重要。
