SUPPRESSOR OF MAX2 LIKE 6, 7, and 8 Interact with DDB1 BINDING WD REPEAT DOMAIN HYPERSENSITIVE TO ABA DEFICIENT 1 to Regulate the Drought Tolerance and Target SUCROSE NONFERMENTING 1 RELATED PROTEIN KINASE 2.3 to Abscisic Acid Response in Arabidopsis

Biomolecules. 2023 Sep 18;13(9):1406. doi: 10.3390/biom13091406.

Abstract

SUPPRESSOR OF MAX2-LIKE 6, 7, and 8 (SMXL6,7,8) function as repressors and transcription factors of the strigolactone (SL) signaling pathway, playing an important role in the development and stress tolerance in Arabidopsis thaliana. However, the molecular mechanism by which SMXL6,7,8 negatively regulate drought tolerance and ABA response remains largely unexplored. In the present study, the interacting protein and downstream target genes of SMXL6,7,8 were investigated. Our results showed that the substrate receptor for the CUL4-based E3 ligase DDB1-BINDING WD-REPEAT DOMAIN (DWD) HYPERSENSITIVE TO ABA DEFICIENT 1 (ABA1) (DWA1) physically interacted with SMXL6,7,8. The degradation of SMXL6,7,8 proteins were partially dependent on DWA1. Disruption of SMXL6,7,8 resulted in increased drought tolerance and could restore the drought-sensitive phenotype of the dwa1 mutant. In addition, SMXL6,7,8 could directly bind to the promoter of SUCROSE NONFERMENTING 1 (SNF1)-RELATED PROTEIN KINASE 2.3 (SnRK2.3) to repress its transcription. The mutations in SnRK2.2/2.3 significantly suppressed the hypersensitivity of smxl6/7/8 to ABA-mediated inhibition of seed germination. Conclusively, SMXL6,7,8 interact with DWA1 to negatively regulate drought tolerance and target ABA-response genes. These data provide insights into drought tolerance and ABA response in Arabidopsis via the SMXL6,7,8-mediated SL signaling pathway.

Keywords: DWA1; SMXL6,7,8; SnRKs; abscisic acid; drought tolerance; strigolactone.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Abscisic Acid / pharmacology
  • Arabidopsis* / genetics
  • DNA-Binding Proteins / genetics
  • Drought Resistance
  • Humans
  • Hypersensitivity*
  • Sucrose
  • Transcription Factors / genetics
  • WD40 Repeats

Substances

  • Abscisic Acid
  • Transcription Factors
  • GR24 strigolactone
  • Sucrose
  • DDB1 protein, human
  • DNA-Binding Proteins

Grants and funding

This research was funded by the National Natural Science Foundation of China (NSFC) (Grant Nos. 31770199 and 31700215); the Foundation of the Key Laboratory of Cell Activities and Stress Adaptations, Ministry of Education of China (lzujbky-2021-kb05); the Fundamental Research Funds for the Central Universities (lzujbky-2021-43), the Startup Foundation for Introducing Talent of Lanzhou University (561120206), and the Natural Science Foundation of Gansu Province, Gansu Excellent Doctoral Program (No. 22JR5RA415).