Vineyard calcium (Ca) sprays have been increasingly used by grape growers to improve fruit firmness and thus maintain quality, particularly in periods of heavy rains and hail. The observation that Ca visibly modified berry size, texture, and color in the most prominent white cultivar of the DOC region 'Vinhos Verdes', cultivar (cv.) Loureiro, led us to hypothesize that Ca induced metabolic rearrangements that resulted in a substantial delay in fruit maturation. Targeted metabolomics by ultra-performance liquid chromatography coupled to mass spectrometry and directed transcriptomics were thus combined to characterize the metabolic and transcriptional profiles of cv. Loureiro berries that, together with firmness, °Brix, and fruit weight measurements, allowed to obtain an integrated picture of the biochemical and structural effects of Ca in this cultivar. Results showed that exogenous Ca decreased amino acid levels in ripe berries while upregulating PAL1 expression, and stimulated the accumulation of caftaric, coutaric, and fertaric acids. An increase in the levels of specific stilbenoids, namely E-piceid and E-ω-viniferin, was observed, which correlated with the upregulation of STS expression. Trace amounts of anthocyanins were detected in berries of this white cultivar, but Ca treatment further inhibited their accumulation. The increased berry flavonol content upon Ca treatment confirmed that Ca delays the maturation process, which was further supported by an increase in fruit firmness and decrease in weight and °Brix at harvest. This newly reported effect may be specific to white cultivars, a topic that deserves further investigation.

中文翻译：

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外源钙延迟白葡萄浆果成熟。Loureiro 同时增加水果硬度和黄酮醇含量。

葡萄种植者越来越多地使用葡萄园钙 (Ca) 喷雾剂来提高果实硬度，从而保持质量，尤其是在大雨和冰雹时期。观察到 Ca 明显改变了 DOC 地区最突出的白色品种“Vinhos Verdes”的浆果大小、质地和颜色，品种 (cv.) Loureiro，使我们假设 Ca 诱导了代谢重排，导致了显着延迟在果实成熟过程中。因此，将超高效液相色谱与质谱联用的靶向代谢组学和定向转录组学相结合，以表征 cv. 的代谢和转录谱。Loureiro 浆果，连同硬度、°Brix 和果实重量测量值，允许获得该品种中 Ca 的生化和结构影响的综合图片。结果表明，外源 Ca 降低成熟浆果中的氨基酸水平，同时上调 PAL1 表达，并刺激 caftaric、coutaric 和 fertaric 酸的积累。观察到特定芪类的水平增加，即 E-piceid 和 E-ω-viniferin，这与 STS 表达的上调相关。在这个白色品种的浆果中检测到微量的花青素，但钙处理进一步抑制了它们的积累。Ca 处理后浆果黄酮醇含量的增加证实了 Ca 延迟了成熟过程，这进一步得到了果实硬度增加和收获时重量和°Brix 的降低的支持。这种新报告的效果可能是白色品种特有的，