Tomato BZR/BES transcription factor SlBZR1 positively regulates BR signaling and salt stress tolerance in tomato and Arabidopsis. (January 2021)

• Record Type: Journal Article
• Authors: Jia, Chengguo; Zhao, Shengke; Bao, Tingting; Zhao, Peiqing; Peng, Kuan; Guo, Qingxun; Gao, Xiang; Qin, Jianchun
• Is Part Of: Plant science. Volume 302(2021)
• Publication Date: 2021-01
• Subjects: Brassinosteroids -- BR signaling pathway -- SlBZR1 -- Tomato -- Salt stress; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2020.110719
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: SlBZR1 is a transcriptional repressor and localized in nucleus. SlBZR1 interacts with SlMYB30, SlMYBL2, SlPIF4, SlHAT1, SlIWS1 and SlREF6. SlBZR1D positively regulates BR signaling and salt tolerance. SlBZR1D upregulates the expression of many stress-responsive genes in tomato. Abstract: Brassinosteroids (BRs) play critical roles in plant growth and development, as well as in responses to abiotic stresses. The BRASSINAZOLE RESISTANT 1 (BZR1) and BRI1-EMS-SUPPRESSOR 1 (BES1) families of transcription factors have been elucidated largely in Arabidopsis and rice but not in other plant species. Here, we studied the functional characterization of a tomato ( Solanum lycopersicum ) BZR homolog gene, SlBZR1, in BR-regulated plant growth and tolerance to salt stress. SlBZR1 was highly expressed in the flowers and developing fruits of tomato. Both SlBZR1 and SlBZR1D (proline to leucine mutation at the 239th amino acid of SlBZR1) were transcriptional repressors and localized in the nucleus. SlBZR1 or SlBZR1D could interact with SlMYB30, SlMYBL2, SlPIF4, SlHAT1, SlIWS1 and SlREF6 in tomato. Overexpression of SlBZR1D enhanced the BR response and improved tolerance to salt stress in Arabidopsis, consistent with the phenotype of the Arabidopsis bes1-D mutant. Moreover, SlBZR1D -overexpressing tomato lines showed a short plant height, smaller and curly leaves, and delayed flowering. Additionally, SlBZR1D positively regulated salt tolerance in tomato and upregulated the expression of multiple stress-related genes. Our study provides new insights for understanding the function and mechanism of BZR transcription factors in BR-regulated plant growth and abiotic stress responses.