The BR signaling pathway regulates primary root development and drought stress response by suppressing the expression of PLT1 and PLT2 in Arabidopsis thaliana

Zhiying Zhao; Shuting Wu; Han Gao; Wenqiang Tang; Xuedan Wu; Baowen Zhang

doi:10.3389/fpls.2023.1187605

The BR signaling pathway regulates primary root development and drought stress response by suppressing the expression of PLT1 and PLT2 in Arabidopsis thaliana

Front Plant Sci. 2023 Jun 27:14:1187605. doi: 10.3389/fpls.2023.1187605. eCollection 2023.

Authors

Zhiying Zhao^{1

2}, Shuting Wu¹, Han Gao¹, Wenqiang Tang¹, Xuedan Wu¹, Baowen Zhang¹

Affiliations

¹ 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.
² Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China.

Abstract

Introduction: 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.

Results and methods: In this study, we found that PLT1 and PLT2, two important transcription factors of root development in Arabidopsis thaliana, 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 PLT1 and inhibit its transcriptional activity in vitro and in vivo. PLT1 and PLT2 were regulated by BR signaling in root development and PLT2 could partially rescue the drought sensitivity of bes1-D. In addition, RNA-seq data analysis showed that BR-regulated root genes and PLT1/2 target genes were also regulated by drought; for example, CIPK3, RCI2A, PCaP1, PIP1;5, ERF61 were downregulated by drought and PLT1/2 but upregulated by BR treatment; AAP4, WRKY60, and AT5G19970 were downregulated by PLT1/2 but upregulated by drought and BR treatment; and RGL2 was upregulated by drought and PLT1/2 but downregulated by BR treatment.

Discussion: 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.

Keywords: PLT1; PLT2; brassinosteroids; drought; root.

Grants and funding

This work was supported by the National Science Foundation of China (Grant No. 31700242 to BZ), the China Postdoctoral Science Foundation (2022M713434 to ZZ), the Science and Technology Project of Hebei Education Department (Grant No. BJ2021029 to BZ), the Natural Science Foundation for Excellent Youth Scholars of Hebei Province of China (Grant No. C2021205011 to BZ).