The conserved histone variant H2A.Z is essential for transcriptional regulation; defense responses; and various biological processes in plants, such as growth, development, and flowering. However, little is known about how H2A.Z affects the developmental process and ripening of tomato fruits. Here, we utilized the CRISPR/Cas9 gene-editing system to generate a sl_hta9 sl_hta11 double-mutant, designated sl_h2a.z, and found that these two mutations led to a significant reduction in the fresh weight of tomato fruits. Subsequent messenger RNA (mRNA)-seq results showed that dysfunction of Sl_H2A.Z has profound effects on the reprogramming of genome-wide gene expression at different developmental stages of tomato fruits, indicating a ripening-dependent correlation between Sl_H2A.Z and gene expression regulation in tomato fruits. In addition, the expression of three genes, SlPSY1, SlPDS, and SlVDE, encoding the key enzymes in the biosynthesis pathway of carotenoids, was significantly upregulated in the later ripening stages, which was consistent with the increased contents of carotenoids in sl_h2a.z double-mutant fruits. Overall, our study reveals a role of Sl_H2A.Z in the regulation of carotenoids and provides a resource for the study of Sl_H2A.Z-dependent gene expression regulation. Hence, our results provide a link between epigenetic regulation via histone variants and fruit development, suggesting a conceptual framework to understand how histone variants regulate tomato fruit quality.

中文翻译：

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组蛋白变体 Sl_H2A.Z 在番茄果实成熟过程中调节类胡萝卜素的生物合成和基因表达

保守的组蛋白变体 H2A.Z 对转录调控至关重要。防御反应；以及植物中的各种生物过程，如生长、发育和开花。然而，人们对 H2A.Z 如何影响番茄果实的发育过程和成熟知之甚少。在这里，我们利用 CRISPR/Cas9 基因编辑系统生成了一个sl_hta9 sl_hta11双突变，指定sl_h2a.z，并发现这两个突变导致番茄果实鲜重显着降低。随后的信使 RNA (mRNA)-seq 结果表明，SL_H2A.Z 对番茄果实不同发育阶段全基因组基因表达的重编程具有深远影响，表明两者之间存在成熟依赖性相关性。SL_H2A.Z 与番茄果实中的基因表达调控。此外，三个基因的表达，SLPSY1,PDS， 和SVDE, 编码类胡萝卜素生物合成途径中的关键酶, 在成熟后期显着上调, 这与类胡萝卜素含量增加一致sl_h2a.z双突变果实。总的来说，我们的研究揭示了SL_H2A.Z 在类胡萝卜素的调控中，并为研究SL_H2A.Z 依赖的基因表达调控。因此，我们的结果提供了通过组蛋白变体进行的表观遗传调控与果实发育之间的联系，为理解组蛋白变体如何调节番茄果实质量提供了一个概念框架。