AmMYB24 Regulates Floral Terpenoid Biosynthesis Induced by Blue Light in Snapdragon Flowers

Jianing Han; Tong Li; Xuelian Wang; Xi Zhang; Xiaoning Bai; Huihui Shao; Shaojie Wang; Zenghui Hu; Jing Wu; Pingsheng Leng

doi:10.3389/fpls.2022.885168

AmMYB24 Regulates Floral Terpenoid Biosynthesis Induced by Blue Light in Snapdragon Flowers

Front Plant Sci. 2022 Jul 1:13:885168. doi: 10.3389/fpls.2022.885168. eCollection 2022.

Authors

Jianing Han^{1

2}, Tong Li^{1

2}, Xuelian Wang^{1

2}, Xi Zhang^{1

2}, Xiaoning Bai^{1

2}, Huihui Shao^{1

2}, Shaojie Wang³, Zenghui Hu^{1

2}, Jing Wu^{1

2}, Pingsheng Leng^{1

2}

Affiliations

¹ Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China.
² College of Landscape Architecture, Beijing University of Agriculture, Beijing, China.
³ Institute of Forestry New Technology, Chinese Academy of Forestry, Beijing, China.

Abstract

Floral terpenoid volatiles are impacted by light quality. In snapdragon, blue light can significantly enhance the emissions of ocimene and myrcene and the expression of ocimene synthase (AmOCS) and myrcene synthase (AmMYS). However, the mechanisms underlying the response to blue light are largely unknown. In this study, two transcription factors (TFs), AmMYB24 and AmMYB63 were screened which showed high expression level under blue light. AmMYB24 exhibited synchronous expression with AmOCS. Moreover, AmOCS transcript expression was up-regulated in response to AmMYB24 overexpression. This activation is direct and occurs through binding of AmMYB24 to MYBCORECYCATB1 sites in the AmOCS promoter. In addition, AmMYB24 interacts with the blue light signal key receptor AmCRY1 and the transcriptional activation activity of AmMYB24 was decreased in AmCRY1 silencing flowers. Taken together, our results revealed the regulatory pathway of biosynthesis of ocimene induced by blue light mediated by AmMYB24 and AmCRY1. When snapdragon flowers were exposed to blue light, AmCRY1 was first activated, the light signal is transduced to AmMYB24 through interaction with AmCRY1, and finally AmMYB24 activates AmOCS by binding to its MYBCOREATCYCB1 motif, resulting in abundant ocimene emission.

Keywords: MYB; blue light; floral volatile; snapdragon; terpenoid; transcription factor.