PDF(Pubmed)
Abstract：
Histone posttranslational modifications shape the chromatin landscape of the plant genome and affect gene expression in response to developmental and environmental cues. To date, the role of histone modifications in regulating plant responses to environmental nutrient availability, especially in agriculturally important species, remains largely unknown. We describe the functions of two histone lysine methyltransferases, SET Domain Group 33 (SDG33) and SDG34, in mediating nitrogen (N) responses of shoots and roots in tomato. By comparing the transcriptomes of CRISPR edited tomato lines sdg33 and sdg34 with wild-type plants under N-supplied and N-starved conditions, we uncovered that SDG33 and SDG34 regulate overlapping yet distinct downstream gene targets. In response to N level changes, both SDG33 and SDG34 mediate gene regulation in an organ-specific manner: in roots, SDG33 and SDG34 regulate a gene network including Nitrate Transporter 1.1 (NRT1.1) and Small Auxin Up-regulated RNA (SAUR) genes. In agreement with this, mutations in sdg33 or sdg34 abolish the root growth response triggered by an N-supply; In shoots, SDG33 and SDG34 affect the expression of photosynthesis genes and photosynthetic parameters in response to N. Our analysis thus revealed that SDG33 and SDG34 regulate N-responsive gene expression and physiological changes in an organ-specific manner, thus presenting previously unknown candidate genes as targets for selection and engineering to improve N uptake and usage in crop plants.
摘要：
组蛋白翻译后修饰塑造了植物基因组的染色质景观，并响应于发育和环境线索影响基因表达。迄今为止,组蛋白修饰在调节植物对环境养分利用率的反应中的作用，特别是在农业上重要的物种中，仍然很大程度上未知。我们描述了两种组蛋白赖氨酸甲基转移酶的功能，SET结构域组33（SDG33）和SDG34，在介导番茄芽和根的氮（N）响应中。通过将CRISPR编辑的番茄系sdg33和sdg34的转录组与野生型植物在N供应和N饥饿条件下进行比较，我们发现SDG33和SDG34调节重叠但不同的下游基因靶标。响应N级变化，SDG33和SDG34都以器官特异性方式介导基因调控：在根中，SDG33和SDG34调节包括硝酸盐转运蛋白1.1(NRT1.1)和小生长素上调RNA(SAUR)基因的基因网络。同意这一点，sdg33或sdg34中的突变消除了由N供应引发的根生长反应;在芽中，SDG33和SDG34响应N影响光合作用基因和光合参数的表达。我们的分析因此揭示了SDG33和SDG34以器官特异性方式调节N响应基因的表达和生理变化。因此提出了以前未知的候选基因作为选择和工程的目标，以改善作物中的氮吸收和利用。
