Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, 250014, China.
State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 10085, China.
Appl Microbiol Biotechnol. 2022 Apr;106(8):3033-3049. doi: 10.1007/s00253-022-11897-z. Epub 2022 Apr 4.
Trichoderma viride has a wide range of applications in plant growth promotion, biological control, cellulase production, and biomass utilization. Salinity is a major limitation to Trichoderma strains in the natural environment and fermentation environment, and to improve the adaptability of Trichoderma to salt stress is of great significance to its applications in industry and agriculture. Histone acetylation plays important roles in the regulation of physiological and biochemical processes including various stress responses. GCN5 is the most representative histone acetylase, which plays vital roles in chromatin remodeling of promoters to facilitate the transcription activation. In this paper, we identified a GCN5-encoding gene TvGCN5 in T. viride Tv-1511, and characterized the function and regulating mechanism of TvGCN5-mediated acetylation of histone H3 in the salt adoption of Tv-1511, by constructions of the deletion mutants (Tv-1511-△GCN5) and overexpression mutants (Tv-1511-GCN5-OE) of TvGCN5. Results showed that compared with wild-type Tv-1511, the over-expression of TvGCN5 resulted in the longer mycelia diameter and more biomass under salt stress. Furthermore, Tv-1511-△GCN5 strains obtained the improved sodium (Na) compartmentation and antioxidant capacity by upregulating the transcriptional levels of genes encoding PM H-ATPase, vacuolar H-ATPase, and antioxidant enzymes. Notably, the changes in the transcriptional expressions of these genes are tightly modulated by the TvGCN5-mediated acetylated level of histone H3 in their promoter regions. In all, these results reveal that TvGCN5 plays an important role in stress tolerance of T. viride Tv-1511, and provides potential insight to facilitate the application of epigenetic modulation in the expanding utilization of Trichoderma. KEY POINTS: • Overexpresison of TvGCN5 improves the adoption of T. viride Tv-1511 to salt stress by increasing acetylation level of histone H3 on the promoter regions of sodium-transport and antioxidant-related genes, at H3K9ac, H3K14ac, H3K23ac, and H3K27ac. • Overexprsison of TvGCN5 enhances the ion transport and compartmentation capacity by upregulating the expressions and activities of PM and vacuolar H-ATPase to tolerate salt stress. • Overexprsison of TvGCN5 promotes the antioxidant capacity by increasing the expressions and activities of antioxidant enzymes in response to salt stress.
绿色木霉在促进植物生长、生物防治、纤维素酶生产和生物质利用等方面有广泛的应用。盐度是绿色木霉在自然环境和发酵环境中生存的主要限制因素，提高绿色木霉对盐胁迫的适应能力对其在工农业中的应用具有重要意义。组蛋白乙酰化在各种应激反应等生理生化过程的调节中起着重要作用。GCN5 是最具代表性的组蛋白乙酰转移酶，它在启动子的染色质重塑中发挥着重要作用，促进转录激活。在本文中，我们在绿色木霉 Tv-1511 中鉴定了一个 GCN5 编码基因 TvGCN5，并通过构建 TvGCN5 的缺失突变体（Tv-1511-△GCN5）和过表达突变体（Tv-1511-GCN5-OE），研究了 TvGCN5 介导的组蛋白 H3 乙酰化在 Tv-1511 耐盐中的功能和调控机制。结果表明，与野生型 Tv-1511 相比，TvGCN5 的过表达导致盐胁迫下菌丝直径更长，生物量更多。此外，Tv-1511-△GCN5 菌株通过上调编码质膜 H+-ATP 酶、液泡 H+-ATP 酶和抗氧化酶的基因的转录水平，获得了更好的钠离子（Na）区室化和抗氧化能力。值得注意的是，这些基因的转录表达变化受到 TvGCN5 介导的组蛋白 H3 在其启动子区域乙酰化水平的紧密调控。总之，这些结果表明 TvGCN5 在绿色木霉 Tv-1511 的应激耐受中起着重要作用，为促进表观遗传调控在扩大木霉利用中的应用提供了潜在的见解。
TvGCN5 的过表达通过增加与钠转运和抗氧化相关基因启动子区域组蛋白 H3 的乙酰化水平（在 H3K9ac、H3K14ac、H3K23ac 和 H3K27ac 上），提高了绿色木霉 Tv-1511 的耐盐性。
TvGCN5 的过表达通过上调质膜和液泡 H+-ATP 酶的表达和活性，增强了离子运输和区室化能力，从而耐受盐胁迫。
TvGCN5 的过表达通过增加抗氧化酶的表达和活性来促进抗氧化能力，以应对盐胁迫。
