MdBZR1 and MdBZR1-2like Transcription Factors Improves Salt Tolerance by Regulating Gibberellin Biosynthesis in Apple

Xuxu Wang; Xiude Chen; Qingjie Wang; Min Chen; Xiao Liu; Dongsheng Gao; Dongmei Li; Ling Li

doi:10.3389/fpls.2019.01473

MdBZR1 and MdBZR1-2like Transcription Factors Improves Salt Tolerance by Regulating Gibberellin Biosynthesis in Apple

Front Plant Sci. 2019 Nov 27:10:1473. doi: 10.3389/fpls.2019.01473. eCollection 2019.

Authors

Xuxu Wang^{1

2}, Xiude Chen^{1

2}, Qingjie Wang^{1

2}, Min Chen³, Xiao Liu^{1

2}, Dongsheng Gao^{1

2}, Dongmei Li^{1

2}, Ling Li^{1

2}

Affiliations

¹ College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, China.
² State Key Laboratory of Crop Biology, Shandong Agricultural University, Taian, China.
³ Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.

Abstract

Brassinosteroids (BRs) are a group of plant steroid hormones that play important roles in regulating plant development. In addition, BRs show considerable functional redundancy with other plant hormones such as gibberellins (GAs). BRASSINAZOLE RESISTANT1 (BZR1) and BRI1-EMS-SUPPRESSOR1 (BES1) transcription factors are negative feedback regulators of BR biosynthesis. This study provides evidence for the roles of MdBZR1 and MdBZR1-2like in promoting GA production. These results also show that BRs regulate GA biosynthesis to improve salt tolerance in apple calli. Moreover, this research proposes a regulatory model, in which MdBZR1 and MdBZR1-2like bind to the promoters of GA biosynthetic genes to regulate their expression in a BR-dependent manner. The expression of key GA biosynthetic genes, MdGA20ox1, MdGA20ox2, and MdGA3ox1 in yeast helps to maintain normal growth even under intense salt stress. In summary, this study underscores the roles of MdBZR1 and MdBZR1-2like in improving salt tolerance by regulating GA biosynthesis in apple calli.

Keywords: MdBZR1; MdBZR1-2like; MdGA20ox2; MdGA3ox1; brassinosteroids; gibberellins; salt stress.