Department of Biochemistry and Molecular Biology, University of Nevada, Reno, NV, 89557, USA.
UMR Ecophysiology and Grape Functional Genomics, Institut des Sciences de la Vigne et du Vin, University of Bordeaux, Villenave d'Ornon, France.
BMC Plant Biol. 2020 Jan 28;20(1):41. doi: 10.1186/s12870-020-2251-7.
Grape berry ripening is influenced by climate, the main component of the "terroir" of a place. Light and temperature are major factors in the vineyard that affect berry development and fruit metabolite composition.
To better understand the effect of "place" on transcript abundance during the late stages of berry ripening, Cabernet Sauvignon berries grown in Bordeaux and Reno were compared at similar sugar levels (19 to 26 °Brix (total soluble solids)). Day temperatures were warmer and night temperatures were cooler in Reno. °Brix was lower in Bordeaux berries compared to Reno at maturity levels considered optimum for harvest. RNA-Seq analysis identified 5528 differentially expressed genes between Bordeaux and Reno grape skins at 22°Brix. Weighted Gene Coexpression Network Analysis for all expressed transcripts for all four °Brix levels measured indicated that the majority (75%) of transcript expression differed significantly between the two locations. Top gene ontology categories for the common transcript sets were translation, photosynthesis, DNA metabolism and catabolism. Top gene ontology categories for the differentially expressed genes at 22°Brix involved response to stimulus, biosynthesis and response to stress. Some differentially expressed genes encoded terpene synthases, cell wall enzymes, kinases, transporters, transcription factors and photoreceptors. Most circadian clock genes had higher transcript abundance in Bordeaux. Bordeaux berries had higher transcript abundance with differentially expressed genes associated with seed dormancy, light, auxin, ethylene signaling, powdery mildew infection, phenylpropanoid, carotenoid and terpenoid metabolism, whereas Reno berries were enriched with differentially expressed genes involved in water deprivation, cold response, ABA signaling and iron homeostasis.
Transcript abundance profiles in the berry skins at maturity were highly dynamic. RNA-Seq analysis identified a smaller (25% of total) common core set of ripening genes that appear not to depend on rootstock, vineyard management, plant age, soil and climatic conditions. Much of the gene expression differed between the two locations and could be associated with multiple differences in environmental conditions that may have affected the berries in the two locations; some of these genes may be potentially controlled in different ways by the vinegrower to adjust final berry composition and reach a desired result.
葡萄浆果的成熟受气候影响，气候是产地“风土”的主要组成部分。光照和温度是葡萄园影响浆果发育和果实代谢物组成的主要因素。
为了更好地了解“产地”对浆果成熟后期转录丰度的影响，比较了波尔多和里诺种植的赤霞珠葡萄在相似糖度（19 至 26 °Brix（总可溶性固体））下的情况。里诺的日温较高，夜温较低。与考虑到最佳收获水平的里诺浆果相比，波尔多浆果的 °Brix 较低。在 22°Brix 时，波尔多和里诺葡萄皮之间有 5528 个差异表达基因。对所有 4 个测量 °Brix 水平的所有表达转录本进行加权基因共表达网络分析表明，大多数（75%）转录本表达在两个地点之间有显著差异。常见转录本集的顶级基因本体类别是翻译、光合作用、DNA 代谢和分解代谢。22°Brix 时差异表达基因的顶级基因本体类别涉及对刺激的反应、生物合成和对压力的反应。一些差异表达基因编码萜烯合酶、细胞壁酶、激酶、转运蛋白、转录因子和光受体。大多数生物钟基因在波尔多的转录本丰度较高。波尔多浆果的差异表达基因与种子休眠、光、生长素、乙烯信号、白粉病感染、苯丙烷、类胡萝卜素和萜类代谢有关，而里诺浆果的差异表达基因与水分胁迫、冷响应、ABA 信号和铁稳态有关。
成熟浆果皮中的转录丰度谱高度动态。RNA-Seq 分析确定了一个较小的（总共有 25%）成熟相关基因的共同核心集，这些基因似乎不依赖于砧木、葡萄园管理、植物年龄、土壤和气候条件。两个地点之间的大部分基因表达存在差异，这些差异可能与影响两个地点浆果的多种环境条件有关；其中一些基因可能受到葡萄种植者的不同控制，以调整最终浆果成分并达到预期的结果。
