Shen Wenyun, Zhang Dehui, Zhang Zitong, He Jieqiang, Khalil Arij, Li Xuewei, Ma Fengwang, Guan Qingmei, Niu Chundong
State Key Laboratory for Crop Stress Resistance and High-Efficiency Production/Shaanxi Key Laboratory of Apple, College of Horticulture, Northwest A&F University, Yangling, Shaanxi, China.
College of Horticulture, Shanxi Agricultural University, Jinzhong, China.
Plant Cell Environ. 2025 Jan;48(1):323-337. doi: 10.1111/pce.15136. Epub 2024 Sep 11.
Apple leaf spot is one of the most devastating diseases in the apple industry, caused by Alternaria alternata f. sp mali (A. alternata). SET-domain group (SDG) proteins function as the histone methyltransferases and participate in plant development and stress responses. However, whether SDG proteins are associated with A. alternata resistance is largely unclear. Here, we describe the pathogen-inducible MdSDG26 gene in apple (Malus × domestica). MdSDG26 has two transcript variants that function similarly in catalyzing histone methylation and A. alternata resistance. Transient overexpression of MdSDG26 increased the global levels of H3K4me3 and H3K36me3, whereas knockdown of MdSDG26 only reduced the H3K36me3 level. Transcriptome analysis revealed that MdSDG26 affected the genome-wide transcriptome changes in response to A. alternata infection. ChIP-qPCR analysis demonstrated that MdSDG26 modulates the levels of H3K36me3 and H3K4me3 at both the promoter and exon regions of MdNTL9. As a negative regulator of A. alternata resistance in apples, MdNTL9 plays a pivotal role in MdSDG26-mediated resistance to A. alternata. Therefore, our findings provide compelling evidence for the regulatory function of MdSDG26 in histone methylation and its molecular role in conferring resistance to A. alternata.
苹果叶斑病是苹果产业中最具毁灭性的病害之一，由链格孢苹果专化型（链格孢）引起。SET结构域蛋白家族（SDG）作为组蛋白甲基转移酶发挥作用，并参与植物发育和应激反应。然而，SDG蛋白是否与链格孢抗性相关在很大程度上尚不清楚。在此，我们描述了苹果（苹果属）中病原体诱导的MdSDG26基因。MdSDG26有两个转录变体，它们在催化组蛋白甲基化和链格孢抗性方面功能相似。MdSDG26的瞬时过表达增加了H3K4me3和H3K36me3的整体水平，而MdSDG26的敲低仅降低了H3K36me3水平。转录组分析表明，MdSDG26影响了全基因组转录组对链格孢感染的变化。ChIP-qPCR分析表明，MdSDG26在MdNTL9的启动子和外显子区域调节H3K36me3和H3K4me3的水平。作为苹果对链格孢抗性的负调节因子，MdNTL9在MdSDG26介导的对链格孢的抗性中起关键作用。因此，我们的研究结果为MdSDG26在组蛋白甲基化中的调节功能及其在赋予对链格孢抗性中的分子作用提供了有力证据。
