Garrido Andreia, De Vos Ric C H, Conde Artur, Cunha Ana
Centre of Molecular and Environmental Biology (CBMA), Department of Biology, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
Centre for the Research and Technology of Agro-Environmental and Biological Sciences (CITAB), University of Trás-os-Montes e Alto Douro, Quinta de Prados, 5000-801 Vila Real, Portugal.
Plants (Basel). 2021 Aug 25;10(9):1769. doi: 10.3390/plants10091769.
Viticulture practices that change the light distribution in the grapevine canopy can interfere with several physiological mechanisms, such as grape berry photosynthesis and other metabolic pathways, and consequently impact the berry biochemical composition, which is key to the final wine quality. We previously showed that the photosynthetic activity of exocarp and seed tissues from a white cultivar (Alvarinho) was in fact responsive to the light microclimate in the canopy (low and high light, LL and HL, respectively), and that these different light microclimates also led to distinct metabolite profiles, suggesting a berry tissue-specific interlink between photosynthesis and metabolism. In the present work, we analyzed the transcript levels of key genes in exocarps and seed integuments of berries from the same cultivar collected from HL and LL microclimates at three developmental stages, using real-time qPCR. In exocarp, the expression levels of genes involved in carbohydrate metabolism (), phenylpropanoid (), stilbenoid (), and flavan-3-ol synthesis (, , and ) were highest at the green stage. In seeds, the expression of several genes associated with both phenylpropanoid ( and ) and flavan-3-ol synthesis ( and ) showed a peak at the stage, whereas that of RuBisCO was maintained up to the mature stage. Overall, the HL microclimate, compared to that of LL, resulted in a higher expression of genes encoding elements associated with both photosynthesis ( and ), carbohydrate metabolism (), and photoprotection (carotenoid pathways genes) in both tissues. HL also induced the expression of the gene, which was translated into a higher activity of the FLS enzyme producing flavonol-type flavonoids, whereas the expression of several other flavonoid pathway genes (e.g., , , , and ) was reduced, suggesting a specific role of flavonols in photoprotection of berries growing in the HL microclimate. This work suggests a possible link at the transcriptional level between berry photosynthesis and pathways of primary and secondary metabolism, and provides relevant information for improving the management of the light microenvironment at canopy level of the grapes.
改变葡萄树冠层光照分布的栽培措施会干扰多种生理机制，如葡萄果实光合作用和其他代谢途径，进而影响果实的生化组成，而这是决定葡萄酒最终品质的关键因素。我们之前的研究表明，白葡萄品种（阿尔瓦里尼奥）外果皮和种子组织的光合活性实际上对树冠层的光照微气候（分别为低光和高光，即LL和HL）有响应，并且这些不同的光照微气候还导致了不同的代谢物谱，这表明光合作用和代谢之间存在果实组织特异性的联系。在本研究中，我们使用实时定量PCR分析了在三个发育阶段从HL和LL微气候中采集的同一品种果实的外果皮和种子种皮中关键基因的转录水平。在外果皮中，参与碳水化合物代谢（）、苯丙烷类（）、芪类（）和黄烷 - 3 - 醇合成（、和）的基因表达水平在绿色阶段最高。在种子中，与苯丙烷类（和）以及黄烷 - 3 - 醇合成（和）相关的几个基因的表达在阶段达到峰值，而RuBisCO的表达一直维持到成熟阶段。总体而言，与LL相比，HL微气候导致两个组织中与光合作用（和）、碳水化合物代谢（）以及光保护（类胡萝卜素途径基因）相关的编码元件的基因表达更高。HL还诱导了基因的表达，该基因被翻译成产生黄酮醇类黄酮的FLS酶的更高活性，而其他几个类黄酮途径基因（例如、、、和）的表达则降低，这表明黄酮醇在HL微气候中生长的果实光保护中具有特定作用。这项工作表明果实光合作用与初级和次级代谢途径之间在转录水平上可能存在联系，并为改善葡萄树冠层光照微环境的管理提供了相关信息。
