Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610065, China.
Genes (Basel). 2022 Dec 10;13(12):2324. doi: 10.3390/genes13122324.
The fast-growing arbor poplar is widely distributed across the world and is susceptible to nitrogen availability. The WRKY transcription factor is an important regulatory node of stress tolerance as well as nutrient utilization. However, the potential response mechanism of genes toward nitrogen is poorly understood. Therefore, the identification of genes on the genome was performed, and 98 (i.e., to ) were identified. Phylogenetic analysis and the promoter cis-acting element detection revealed that PtWRKYs have multiple functions, including phosphorus and nitrogen homeostasis. By constructing multilayer-hierarchical gene regulatory networks (ML-hGRNs), it was predicted that many WRKY transcription factors were involved in the nitrogen response, such as PtWRKY33 and PtWRKY95. They mainly regulated the expression of primary nitrogen-responsive genes (NRGs), such as , and . The integrative analysis of transcriptome and RT-qPCR results show that the expression levels of 6 and 15 were regulated by nitrogen availability in roots and leaves, respectively, and those were also found in ML-hGRN. Our study demonstrates that PtWRKYs respond to nitrogen by regulating NRGs, which enriches the nitrate-responsive transcription factor network and helps to uncover the hub of nitrate and its related signaling regulation.
速生杨树在世界范围内广泛分布，对氮素可用性敏感。WRKY 转录因子是一种重要的应激耐受和养分利用的调控节点。然而，基因对氮的潜在响应机制还知之甚少。因此，对基因组上的基因进行了鉴定，鉴定出了 98 个 PtWRKY 基因（即 26.67%）。系统发育分析和启动子顺式作用元件检测表明，PtWRKYs 具有多种功能，包括磷和氮的稳态。通过构建多层次基因调控网络（ML-hGRNs），预测许多 WRKY 转录因子参与了氮响应，如 PtWRKY33 和 PtWRKY95。它们主要调节初级氮响应基因（NRGs）的表达，如 、 和 。转录组和 RT-qPCR 结果的综合分析表明，6 和 15 的表达水平分别受根和叶中氮可用性的调节，并且在 ML-hGRN 中也发现了这种调节。我们的研究表明，PtWRKYs 通过调节 NRGs 对氮做出响应，这丰富了硝酸盐响应转录因子网络，并有助于揭示硝酸盐及其相关信号调控的枢纽。
