Data_Sheet_1_Normal distribution of H3K9me3 occupancy co-mediated by histone methyltransferase BcDIM5 and histone deacetylase BcHda1 maintains stable ABA synthesis in Botrytis cinerea TB-31.pdf

Abscisic acid (ABA) is a conserved and important “sesquiterpene signaling molecule” widely distributed in different organisms with unique biological functions. ABA coordinates reciprocity and competition between microorganisms and their hosts. In addition, ABA also regulates immune and stress responses in plants and animals. Therefore, ABA has a wide range of applications in agriculture, medicine and related fields. The plant pathogenic ascomycete B. cinerea has been extensively studied as a model strain for ABA production. Nevertheless, there is a relative dearth of research regarding the regulatory mechanism governing ABA biosynthesis in B. cinerea. Here, we discovered that H3K9 methyltransferase BcDIM5 is physically associated with the H3K14 deacetylase BcHda1. Deletion of Bcdim5 and Bchda1 in the high ABA-producing B. cinerea TB-31 led to severe impairment of ABA synthesis. The combined analysis of RNA-seq and ChIP-seq has revealed that the absence of BcDIM5 and BcHda1 has resulted in significant global deficiencies in the normal distribution and level of H3K9me3 modification. In addition, we found that the cause of the decreased ABA production in the ΔBcdim5 and ΔBchda1 mutants was due to cluster gene repression caused by the emergence of hyper-H3K9me3 in the ABA gene cluster. We concluded that the ABA gene cluster is co-regulated by BcDIM5 and BcHda1, which are essential for the normal distribution of the B. cinerea TB-31 ABA gene cluster H3K9me3. This work expands our understanding of the complex regulatory network of ABA biosynthesis and provides a theoretical basis for genetic improvement of high-yielding ABA strains.

脱落酸（Abscisic acid, ABA）是一类保守且重要的“倍半萜信号分子（sesquiterpene signaling molecule）”，广泛分布于各类生物体内，具备独特的生物学功能。ABA可协调微生物与其宿主之间的互惠与竞争关系。此外，ABA还能调控动植物的免疫与应激响应。因此，ABA在农业、医药及相关领域拥有广泛的应用价值。
植物病原子囊菌灰葡萄孢（B. cinerea）作为ABA生产的模式菌株已被广泛研究。然而，目前关于灰葡萄孢中ABA生物合成的调控机制，相关研究仍相对匮乏。
本研究发现，组蛋白H3赖氨酸9甲基转移酶（H3K9 methyltransferase）BcDIM5与组蛋白H3赖氨酸14去乙酰化酶（H3K14 deacetylase）BcHda1存在物理相互作用。在高ABA产率的灰葡萄孢菌株TB-31中敲除Bcdim5和Bchda1，会严重损害ABA的合成能力。
通过RNA测序（RNA-seq）与染色质免疫沉淀测序（ChIP-seq）的联合分析，研究发现BcDIM5和Bchda1的缺失会导致全基因组范围内H3K9me3修饰的正常分布与水平出现显著异常。
此外，本研究证实，ΔBcdim5和ΔBchda1突变体的ABA产量下降，是由于ABA基因簇区域出现H3K9me3过度富集，进而引发簇内基因的转录抑制。
本研究表明，ABA基因簇受BcDIM5与Bchda1共同调控，这两种蛋白对于维持灰葡萄孢TB-31的ABA基因簇H3K9me3的正常分布至关重要。
本研究拓展了学界对ABA生物合成复杂调控网络的认知，为高产ABA菌株的遗传改良提供了坚实的理论基础。