Baldwin Ashley, Lechon Tamara, Marchbank Angela, Scofield Simon, Lieu Kerstin, Wilson Charlotte L, Ludlow Richard A, Herbert Robert J, Nützmann Hans-Wilhelm, Rogers Hilary J
School of Biosciences, Cardiff University, Sir Martin Evans Building, Museum Avenue, Cardiff CF10 3AX, UK.
School of Science and the Environment, University of Worcester, Henwick Grove, Worcester WR2 6AJ, UK.
J Exp Bot. 2025 Jun 17;76(9):2487-2499. doi: 10.1093/jxb/erae464.
Strawberry ripening is non-climacteric, and post-harvest fruit enter senescence and deteriorate rapidly. Chilled storage induces transcriptome-wide changes in gene expression, including down-regulation of aroma-related genes. Histone marks are associated with transcriptional activation or repression; the H3K27me3 mark is mainly associated with repression of gene expression. Here genes associated with H3K27me3 were identified through ChIP-seq in ripe red strawberry fruit at harvest and after 5 d of chilled storage in the dark. The number of ChIP peaks increased with storage time, indicating an increased role for this mark in regulation of gene expression following chilled dark storage. Comparing ChIP-seq data with RNA-seq data from the same material identified 440 genes whose expression correlated with H3K27me3 repression. Abiotic stress genes, especially cold stress response genes, were down-regulated during storage. Increased association with the H3K27me3 mark indicated that they may be repressed via this epigenetic mark. Other functional groups included cell wall and carbohydrate metabolism. The association with the H3K27me3 mark of two transcription factor genes (FaHY5 and FaTRAB1) and of FaADH, involved in ester biosynthesis, was validated by ChIP-PCR. These three genes were all down-regulated during storage and indicated a network of H3K27me3 gene repression affecting both anthocyanin and ester biosynthesis.
草莓成熟是非跃变型的，采后果实进入衰老阶段并迅速变质。冷藏会引起基因表达在全转录组范围内的变化，包括与香气相关基因的下调。组蛋白标记与转录激活或抑制相关；H3K27me3标记主要与基因表达的抑制相关。在此，通过染色质免疫沉淀测序（ChIP-seq）在收获时的成熟红草莓果实以及在黑暗中冷藏5天后的果实中鉴定出与H3K27me3相关的基因。ChIP峰的数量随储存时间增加，表明该标记在冷藏黑暗储存后基因表达调控中的作用增强。将ChIP-seq数据与来自相同材料的RNA-seq数据进行比较，鉴定出440个基因，其表达与H3K27me3抑制相关。非生物胁迫基因，尤其是冷胁迫响应基因，在储存期间下调。与H3K27me3标记的关联增加表明它们可能通过这种表观遗传标记被抑制。其他功能组包括细胞壁和碳水化合物代谢。通过ChIP-PCR验证了两个转录因子基因（FaHY5和FaTRAB1）以及参与酯生物合成的FaADH与H3K27me3标记的关联。这三个基因在储存期间均下调，表明存在一个影响花青素和酯生物合成的H3K27me3基因抑制网络。
