Department of Biological Sciences, Indian Institute of Science Education and Research Mohali, Punjab 140306, India.
Defence Institute of High Altitude Research Leh, Ladakh 901205, India.
Plant Physiol. 2020 Dec;184(4):2091-2106. doi: 10.1104/pp.20.01304. Epub 2020 Oct 21.
Understanding how the distinct cell types of the shoot apical meristem (SAM) withstand ultraviolet radiation (UVR) stress can improve cultivation of plants in high-UVR environments. Here, we show that UV-B irradiation selectively kills epidermal and niche cells in the shoot apex. Plants harboring a mutation in () are tolerant to UV-B. Our data show that DEWAX negatively regulates genes involved in anthocyanin biosynthesis. ELONGATED HYPOCOTYL5 (HY5) binds to the promoter elements and represses its expression to promote the anthocyanin biosynthesis. The HY5-DEWAX regulatory network regulates anthocyanin content in Arabidopsis () and influences the survivability of plants under UV-B irradiation stress. Our cell sorting-based study of the epidermal cell layer transcriptome confirms that core UV-B stress signaling pathway genes are conserved and upregulated in response to UV-B irradiation of the SAM. Furthermore, we show that UV-B induces genes involved in shoot development and organ patterning. We propose that the HY5-DEWAX regulatory relationship is conserved; however, changes in the expression levels of these genes can determine anthocyanin content in planta and, hence, fitness under UV-B irradiation stress.
了解茎尖分生组织 (SAM) 中不同类型的细胞如何耐受紫外线辐射 (UVR) 应激，可以提高在高 UVR 环境中植物的栽培水平。在这里，我们表明 UV-B 辐射选择性地杀死茎尖的表皮细胞和小生境细胞。携带 () 突变的植物对 UV-B 具有耐受性。我们的数据表明，DEWAX 负调控参与类黄酮生物合成的基因。ELONGATED HYPOCOTYL5 (HY5) 与 启动子元件结合并抑制其表达，以促进类黄酮的生物合成。HY5-DEWAX 调控网络调节拟南芥中的类黄酮含量，并影响植物在 UV-B 辐射胁迫下的存活率。我们基于细胞分选的表皮细胞层转录组研究证实，核心 UV-B 应激信号通路基因在 SAM 受到 UV-B 照射时保守上调。此外，我们表明 UV-B 诱导与芽发育和器官模式形成相关的基因。我们提出，HY5-DEWAX 调控关系是保守的；然而，这些基因表达水平的变化可以决定植物体内类黄酮的含量，从而影响植物在 UV-B 辐射胁迫下的适应性。
