Rumbaugh Arran, Medina-Plaza Cristina, Sudarshana Mysore R, Oberholster Anita
United States Department of Agriculture, Department of Viticulture and Enology, University of California Davis, Davis, CA, USA.
Department of Viticulture & Enology, University of California Davis, Davis, CA, USA.
J Sci Food Agric. 2023 May;103(7):3457-3467. doi: 10.1002/jsfa.12481. Epub 2023 Feb 20.
Grapevine red blotch virus (GRBV) is the causal agent of grapevine red blotch disease and is known to delay grape ripening. However, grape cell-wall modifications during GRBV infection are largely unknown, even though the cell wall plays a large role in pathogenicity, viral interactions with host plants, and phenolic extractability during winemaking. Understanding the impact of GRBV infection on cell-wall metabolism is important for the development of potential mitigations strategies. In this study, high-throughput transcriptome sequencing was conducted on Vitis vinifera L. 'Merlot' grapes during ripening. The cell-wall composition, phenolic content, and phenolic extractability at two different commercial harvest points were also determined.
Log fold changes indicated a strong induction in diseased grapes at harvest of several transcripts involved in cell-wall solubilization and degradation. However, these observations did not translate to changes in cell-wall composition at either harvest point in diseased grapes, potentially suggesting post-transcriptional regulation. Moderate induction of pectin methylesterase inhibitor transcripts and transcripts associated with pathogenesis-related proteins coincided with increases in pectin and soluble proteins in cell walls of diseased grapes at harvest. Both pectin and pathogenesis-related proteins are known to retain phenolic compounds during winemaking.
Our study corroborates this finding when the percentage extractability of flavonols in wines was significantly lower when made from GRBV-infected fruit. These results suggest GRBV alters the grape cell walls, consequently decreasing phenolic extraction during winemaking. © 2023 Society of Chemical Industry.
葡萄红环斑病毒（GRBV）是葡萄红环斑病的病原体，已知会延迟葡萄成熟。然而，尽管细胞壁在致病性、病毒与寄主植物的相互作用以及酿酒过程中的酚类可提取性方面发挥着重要作用，但GRBV感染期间葡萄细胞壁的修饰情况仍 largely 未知。了解GRBV感染对细胞壁代谢的影响对于制定潜在的缓解策略很重要。在本研究中，对成熟过程中的酿酒葡萄品种‘梅洛’进行了高通量转录组测序。还测定了两个不同商业采收点的细胞壁组成、酚类含量和酚类可提取性。
对数倍变化表明，在采收时，患病葡萄中几种参与细胞壁溶解和降解的转录本有强烈诱导。然而，这些观察结果并未转化为患病葡萄在任一采收点的细胞壁组成变化，这可能表明存在转录后调控。果胶甲酯酶抑制剂转录本和与病程相关蛋白相关的转录本的适度诱导与采收时患病葡萄细胞壁中果胶和可溶性蛋白的增加相吻合。已知果胶和病程相关蛋白在酿酒过程中都会保留酚类化合物。
当用感染GRBV的果实酿造的葡萄酒中黄酮醇的可提取百分比显著降低时，我们的研究证实了这一发现。这些结果表明GRBV改变了葡萄细胞壁，从而降低了酿酒过程中的酚类提取。© 2023化学工业协会。
