Zhao Zhiying, Wu Shuting, Gao Han, Tang Wenqiang, Wu Xuedan, Zhang Baowen
Ministry of Education Key Laboratory of Molecular and Cellular Biology; Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaboration Innovation Center for Cell Signaling and Environmental Adaptation, Hebei Key Laboratory of Molecular and Cellular Biology, College of Life Sciences, Hebei Normal University, Shijiazhuang, China.
Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.
Front Plant Sci. 2023 Jun 27;14:1187605. doi: 10.3389/fpls.2023.1187605. eCollection 2023.
With the warming global climate, drought stress has become an important abiotic stress factor limiting plant growth and crop yield. As the most rapidly drought-sensing organs of plants, roots undergo a series of changes to enhance their ability to absorb water, but the molecular mechanism is unclear.
In this study, we found that PLT1 and PLT2, two important transcription factors of root development in , are involved in the plant response to drought and are inhibited by BR signaling. PLT1- and PLT2-overexpressing plants showed greater drought tolerance than wild-type plants. Furthermore, we found that BZR1 could bind to the promoter of and inhibit its transcriptional activity and . and were regulated by BR signaling in root development and could partially rescue the drought sensitivity of . In addition, RNA-seq data analysis showed that BR-regulated root genes and PLT1/2 target genes were also regulated by drought; for example, , , , , were downregulated by drought and PLT1/2 but upregulated by BR treatment; , , and were downregulated by PLT1/2 but upregulated by drought and BR treatment; and was upregulated by drought and PLT1/2 but downregulated by BR treatment.
Our findings not only reveal the mechanism by which BR signaling coordinates root growth and drought tolerance by suppressing the expression of PLT1 and PLT2 but also elucidates the relationship between drought and root development. The current study thus provides an important theoretical basis for the improvement of crop yield under drought conditions.
随着全球气候变暖，干旱胁迫已成为限制植物生长和作物产量的重要非生物胁迫因素。作为植物最快速感知干旱的器官，根会发生一系列变化以增强其吸水能力，但其分子机制尚不清楚。
在本研究中，我们发现拟南芥根发育的两个重要转录因子PLT1和PLT2参与植物对干旱的响应，并受到油菜素内酯（BR）信号的抑制。过表达PLT1和PLT2的植物比野生型植物表现出更强的耐旱性。此外，我们发现BZR1可以结合PLT1和PLT2的启动子并抑制其转录活性。PLT1和PLT2在根发育中受BR信号调控，并且可以部分挽救PLT1和PLT2缺失突变体的干旱敏感性。此外，RNA测序数据分析表明，BR调控的根基因和PLT1/2靶基因也受干旱调控；例如，AtHKT1;1、AtPIP2;1、AtPIP2;2、AtTIP2;1和AtNRT2;1受干旱和PLT1/2下调，但受BR处理上调；AtWRKY40、AtMYB77和AtABI5受PLT1/2下调，但受干旱和BR处理上调；AtERF6受干旱和PLT1/2上调，但受BR处理下调。
我们的研究结果不仅揭示了BR信号通过抑制PLT1和PLT2的表达来协调根生长和耐旱性的机制，还阐明了干旱与根发育之间的关系。因此，本研究为干旱条件下提高作物产量提供了重要的理论依据。
