Vergara Ricardo, Noriega Ximena, Aravena Karla, Prieto Humberto, Pérez Francisco J
Laboratorio de Bioquímica Vegetal, Facultad de Ciencias, Universidad de ChileSantiago, Chile.
Programa Doctorado en Ciencias Silvoagropecuarias y Veterinarias, Universidad de ChileSantiago, Chile.
Front Plant Sci. 2017 May 19;8:812. doi: 10.3389/fpls.2017.00812. eCollection 2017.
Recently, the plant hormone abscisic acid (ABA) has been implicated as a key player in the regulation of endodormancy (ED) in grapevine buds ( L). In this study, we show that in the vine, the expression of genes related to the biosynthesis of ABA () and the content of ABA are significantly higher in the latent bud than at the shoot apex, while the expression of an ABA catabolic gene () showed no significant difference between either organ. A negative correlation between the content of ABA and transcript levels of cell cycle genes (CCG) was found in both tissues. This result suggested that ABA may negatively regulate the expression of CCG in meristematic tissues of grapevines. To test this proposition, the effect of ABA on the expression of CCG was analyzed in two meristematic tissues of the vine: somatic embryos and shoot apexes. The results indicated that cell cycle progression is repressed by ABA in both organs, since it down-regulated the expression of genes encoding cyclin-dependent kinases () and genes encoding cyclins of type A (), B (), and D () and up-regulated the expression of , a gene encoding an inhibitor of CDKs. During ED, the content of ABA increased, and the expression of CCG decreased. Moreover, the dormancy-breaking compound hydrogen cyanamide (HC) reduced the content of ABA and up-regulated the expression of CCG, this last effect was abolished when HC and ABA were co-applied. Taken together, these results suggest that ABA-mediated repression of CCG transcription may be part of the mechanism through which ABA modulates the development of ED in grapevine buds.
最近，植物激素脱落酸（ABA）被认为是葡萄芽内休眠（ED）调控中的关键因子。在本研究中，我们发现，在葡萄植株中，与ABA生物合成相关的基因（）的表达以及ABA的含量在潜伏芽中显著高于茎尖，而一个ABA分解代谢基因（）的表达在这两个器官之间没有显著差异。在这两个组织中均发现ABA含量与细胞周期基因（CCG）转录水平呈负相关。这一结果表明，ABA可能对葡萄分生组织中CCG的表达起负调控作用。为验证这一观点，我们在葡萄的两个分生组织——体细胞胚和茎尖中分析了ABA对CCG表达的影响。结果表明，ABA在这两个器官中均抑制细胞周期进程，因为它下调了编码细胞周期蛋白依赖性激酶（）的基因以及编码A（）、B（）和D（）型细胞周期蛋白的基因的表达，并上调了编码CDK抑制剂的基因的表达。在ED期间，ABA含量增加，CCG表达下降。此外，破眠化合物氰胺（HC）降低了ABA含量并上调了CCG的表达，当HC与ABA共同施用时，后一种效应被消除。综上所述，这些结果表明，ABA介导的对CCG转录的抑制可能是ABA调节葡萄芽内休眠发育机制的一部分。
