Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Braga, Portugal; Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Vila Real, Portugal.
UMR EGFV, Bordeaux Sciences Agro, INRAE, Université de Bordeaux, 210 Chemin de Leysotte, CS 50008, Villenave d'Ornon, 33882, France.
Plant Sci. 2021 Oct;311:110984. doi: 10.1016/j.plantsci.2021.110984. Epub 2021 Jun 22.
Perennial woody plants undergo a period of dormancy from the beginning of autumn until the end of spring. Whereas the molecular and physiological events that characterize dormancy release of buds have been described in detail, those occurring in woody tissues underneath the buds are mostly unknown. To bridge this gap, the mRNA populations of cane segments located underneath the bud were analyzed at bud dormancy (E-L 1) and at bud burst (E-L 4). They revealed an important reprogramming of gene expression suggesting that cell division, cell wall metabolism and the mobilization of sugars are the main metabolic and cellular events occurring in cane woody tissues at bud burst. Also, the upregulation of several genes of sugar metabolism, encoding starch- and sucrose-degrading enzymes and sugar transporters, correlates with the decrease in starch and soluble sugars in woody tissues concomitant with increased sucrose synthase and α-amylolytic biochemical activities. The latter is likely due to the VviAMY2 gene that encodes a functional α-amylase as observed after its heterologous expression in yeast. Taken together, these results are consistent with starch and sugar mobilization in canes being primarily involved in grapevine secondary growth initiation and supporting the growth of the emerging bud.
多年生木本植物从初秋开始经历一个休眠期，直到春季末。尽管已经详细描述了芽休眠释放的特征性分子和生理事件，但芽下木质组织中发生的事件大多未知。为了弥补这一空白，在芽休眠（E-L1）和芽萌发（E-L4）时分析了位于芽下的嫩枝段的 mRNA 群体。结果显示基因表达的重要重编程表明，细胞分裂、细胞壁代谢和糖的动员是芽萌发时嫩枝木质组织中发生的主要代谢和细胞事件。此外，糖代谢的几个基因上调，这些基因编码淀粉和蔗糖降解酶和糖转运蛋白，与木质组织中淀粉和可溶性糖的减少以及蔗糖合酶和α-淀粉酶生化活性的增加相关。后者可能与 VviAMY2 基因有关，该基因编码一种功能性的α-淀粉酶，如在酵母中异源表达后观察到的那样。综上所述，这些结果与葡萄藤次生生长启动过程中主要涉及的茎中淀粉和糖的动员相一致，并支持新萌发芽的生长。
