科研成果

Plant J-尹若贺课题组发现番茄SPA3蛋白调控紫外光信号响应新机理

发布时间:2024-11-12 

   番茄是一种重要的设施蔬菜,设施番茄生产中的弱光问题影响番茄的产量和果实品质。研究表明紫外光UV-B信号通路能够有效的抑制番茄的弱光徒长问题,改善番茄果实代谢,增强番茄果实着色。然而紫外光UV-B信号转导调控番茄发育和代谢的机理有待深入研究。近日,中心尹若贺课题组与合作者在The Plant Journal杂志发表了题为SlSPA3 regulates the nuclear abundance of SlUVR8 in tomato的研究论文,揭示了番茄SPA3蛋白在响应紫外光UV-B信号调控番茄光形态建成中的作用机理。

  紫外光UV-B (280-315nm) 可以诱导紫外光受体UVR8由二体解离成单体并转运到细胞核中, UVR8在细胞核中积累,调控下游基因表达,从而调控植物的生长以及代谢物积累等生理表型。之前的研究报道显示拟南芥中SPA家族成员可能调节拟南芥的UV-B信号传导,然而,其潜在机制尚不完全清楚。本研究发现了番茄基因组中包含四个潜在的SlSPA基因 (SlSPA1/2/3/4)。基因组编辑的Slspa3突变体在白光下表现出增强的光形态形成反应,表明SlSPA3是光形态建成的负调控因子(图1)。

图1. 白光下,Slspa3 突变体较野生型番茄有更强的光形态建成表型. (A) Hypocotyl length of tomato seedings of Slspa3 mutant lines grown in white light for 4 days. Values are means ± SD (n ≥ 9). (B) Anthocyanin levels in Slspa3 mutants. Seedlings were grown in white light for 2 days or 4 days. Values are means ± SD from three biological replicates (n = 3). Different letters in Figure A and B indicate significant differences between means; Significant differences were determined by one-way ANOVA with Tukey's HSD test (P < 0.05).

  除此之外,在Slspa3突变体中,UVR8介导的UV-B应答基因表达以及花青素含量较野生型明显下降,表明SlSPA3促进UV-B光形态建成。此外, 由于SlSPA3和SlCOP1直接互作,且拟南芥的COP1调控UVR8的核积累,本研究探测了SlSPA3是否调控SlUVR8的核积累,实验结果表明在番茄Slspa3单突变体内UV-B诱导下的SlUVR8在细胞核内积累水平较野生型减少,表明SlSPA3通过增强光受体SlUVR8在细胞核内积累,促进紫外光UV-B的光信号转导(图2)。在拟南芥spa1 spa2 spa4三突变体中,UVR8的核积累也明显减少,表明这两个物种之间存在着保守机制。但是,spa1 spa2 spa4三突变体中UV-B依赖的UVR8与COP1之间的相互作用却未发生变化,这表明已知的COP1介导的UVR8的核滞留机制并未被SPAs影响。因此,我们的工作揭示了一种潜在的未被认识的机制,即SPA蛋白通过促进陆地植物UVR8核积累来调节UVB的响应机理。

Figure 2. SPA 提高UV-B-介导的光受体UVR8蛋白在细胞核内积累. (A) UV-B-induced SlUVR8 nuclear accumulation is reduced in tomato Slspa3. 7-DAG white light grown tomato seedlings were either maintained under white light (-) or transferred to white light supplemented with UV-B for 24 h (+). Histone H3 and UGPase served as nuclear and cytosolic controls, respectively. (B) Relative quantification of nuclear and cytosolic SlUVR8 levels. The band intensity of nuclear and cytosolic SlUVR8 was normalized against that of H3 and UGPase, respectively. Both nuclear and cytosolic SlUVR8 levels in WT grown under UV-B were set to 1. Quantification of band intensity was based on three independent experiments. (C) Working model for tomato SPA3 and also Arabidopsis SPA proteins in the regulation of UVR8 nuclear abundance.

  上海交通大学已毕业博士生研究生张倩雯,在读博士生刘月为论文的共同第一作者,尹若贺副教授为论文通讯作者。上海交通大学林丽副研究员和张春丽助理研究员,以及北京大学朱丹萌研究员,希伯来大学 David Weiss教授和 布宜诺斯艾利斯大学的 Carlos L. Ballare教授等参与了本研究工作。本研究得到了国家自然科学基金和上海市自然科学基金等项目的资助。

原文链接:https://onlinelibrary.wiley.com/doi/epdf/10.1111/tpj.17135