Endogenous level of abscisic acid down-regulated by brassinosteroids signaling via BZR1 to control the growth of Arabidopsis thaliana
- Authors
- Moon, Jinyoung; Park, Chan-Ho; Son, Seung-Hyun; Youn, Ji-Hyun; Kim, Seong-Ki
- Issue Date
- 2-Sep-2021
- Publisher
- TAYLOR & FRANCIS INC
- Keywords
- ABA2; abscisic acid biosynthesis; brassinosteroid signaling; bzr1; hormonal interaction
- Citation
- PLANT SIGNALING & BEHAVIOR, v.16, no.9
- Journal Title
- PLANT SIGNALING & BEHAVIOR
- Volume
- 16
- Number
- 9
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/48593
- DOI
- 10.1080/15592324.2021.1926130
- ISSN
- 1559-2316
1559-2324
- Abstract
- The increased level of endogenous abscisic acid (ABA) in brassinosteroid (BR)-deficient mutants, such as det2 and cyp85a1 x cyp85a2, suggests that ABA synthesis is inhibited by endogenous BRs in Arabidopsis thaliana. Expression of the ABA biosynthesis gene ABA-deficient 2 (ABA2) was negatively regulated by exogenously applied BR but up-regulated by the application of brassinazole and in det2 and cyp85a1 x cyp85a2. In addition, ABA2 expression decreased in bzr1-1D, showing that ABA biosynthesis is inhibited by BR signaling via BZR1, intermediated by ABA2, in Arabidopsis. Four cis-element sequences (E-boxes 1-4) in the putative promoter region of ABA2 were identified as BZR1 binding sites. The electrophoretic mobility shift assay and chromatin immune precipitation analysis demonstrated that BZR1 directly binds to overlapped E-boxes (E-box 3/4) in the promoter region of ABA2. The level of endogenous ABA was decreased in bzr1-1D compared to wild-type, indicating that binding of BZR1 to the ABA2 promoter inhibits ABA synthesis in Arabidopsis. Compared to wild-type, aba2-1 exhibited severely reduced growth and development. The abnormalities in aba2-1 were rescued by the application of ABA, suggesting that ABA2 expression and ABA synthesis are necessary for the normal growth and development of A. thaliana. Finally, bzr1-KO x aba2-1 exhibited inhibitory growth of primary roots compared to bzr1-KO, verifying that ABA2 is a downstream target of BZR1 in the plant. Taken together, the level of endogenous ABA is down-regulated by BR signaling via BZR1, controlling the growth of A. thaliana.
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Collections - College of Natural Sciences > Department of Life Science > 1. Journal Articles
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