Soil and Crop Sciences Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853.
Cornell High Energy Synchrotron Source, Cornell University, Ithaca, New York 14853.
Plant Cell. 2017 Dec;29(12):3012-3029. doi: 10.1105/tpc.17.00363. Epub 2017 Nov 7.
A deficiency of the micronutrient copper (Cu) leads to infertility and grain/seed yield reduction in plants. How Cu affects fertility, which reproductive structures require Cu, and which transcriptional networks coordinate Cu delivery to reproductive organs is poorly understood. Using RNA-seq analysis, we showed that the expression of a gene encoding a novel transcription factor, CITF1 (Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR1), was strongly upregulated in flowers subjected to Cu deficiency. We demonstrated that CITF1 regulates Cu uptake into roots and delivery to flowers and is required for normal plant growth under Cu deficiency. CITF1 acts together with a master regulator of copper homeostasis, SPL7 (SQUAMOSA PROMOTER BINDING PROTEIN LIKE7), and the function of both is required for Cu delivery to anthers and pollen fertility. We also found that Cu deficiency upregulates the expression of jasmonic acid (JA) biosynthetic genes in flowers and increases endogenous JA accumulation in leaves. These effects are controlled in part by CITF1 and SPL7. Finally, we show that JA regulates expression and that the JA biosynthetic mutant lacking the CITF1- and SPL7-regulated genes, and , is sensitive to Cu deficiency. Together, our data show that CITF1 and SPL7 regulate Cu uptake and delivery to anthers, thereby influencing fertility, and highlight the relationship between Cu homeostasis, CITF1, SPL7, and the JA metabolic pathway.
微量元素铜（Cu）的缺乏会导致植物不孕和谷物/种子产量下降。Cu 如何影响生育能力、哪些生殖结构需要 Cu 以及哪些转录网络协调 Cu 向生殖器官的输送，这些问题目前还知之甚少。通过 RNA-seq 分析，我们发现一个编码新型转录因子 CITF1（Cu-DEFICIENCY INDUCED TRANSCRIPTION FACTOR1）的基因的表达在受到 Cu 缺乏的花中强烈上调。我们证明 CITF1 调节 Cu 进入根的吸收和向花的输送，并且在 Cu 缺乏下正常植物生长是必需的。CITF1 与铜稳态的主要调节因子 SPL7（SQUAMOSA PROMOTER BINDING PROTEIN LIKE7）一起作用，两者的功能都需要将 Cu 输送到花药和花粉的育性。我们还发现 Cu 缺乏会在上调花中茉莉酸（JA）生物合成基因的表达，并增加叶片中内源性 JA 的积累。这些影响部分受 CITF1 和 SPL7 控制。最后，我们表明 JA 调节 表达，并且缺乏 CITF1 和 SPL7 调节基因的 JA 生物合成突变体 和 对 Cu 缺乏敏感。总之，我们的数据表明 CITF1 和 SPL7 调节 Cu 的吸收和向花药的输送，从而影响生育能力，并强调了 Cu 动态平衡、CITF1、SPL7 和 JA 代谢途径之间的关系。
