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Article|15 Mar 2020|OPEN
PyWRKY26 and PybHLH3 cotargeted the PyMYB114 promoter to regulate anthocyanin biosynthesis and transport in red-skinned pears
Chuang Li1, Jun Wu2, Kang-Di Hu1, Shu-Wei Wei3, Hong-Ye Sun1, Lan-Ying Hu1,4, Zhuo Han1, Gai-Fang Yao1, & Hua Zhang1,
1School of Food and Biological Engineering, Hefei University of Technology, 230009, Hefei, China
2Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 210095 Nanjing, China
3Shandong Institute of Pomology, 271000 Taian, China
4Anhui Province Key Laboratory of Functional Compound Seasoning, Anhui Qiangwang Seasoning Food Co., Ltd., 236500 Jieshou, China

Horticulture Research 7,
Article number: 20037 (2020)
doi: 10.1038/hortres.2020.37
Views: 6021

Received: 03 Aug 2019
Revised: 30 Dec 2019
Accepted: 15 Jan 2020
Published online: 15 Mar 2020

Abstract

Red pear is favored because of its bright appearance and abundant anthocyanins. Anthocyanin biosynthesis is controlled by transcription factors (TFs) forming regulatory complexes. In red-skinned pears, the WRKY TFs have a significant relationship with anthocyanin biosynthesis, but the molecular mechanism of the WRKY TFs involved in regulating color formation in red-skinned pear is unclear. In this study, the TFs PyWRKY31 and PyWRKY26 were screened as candidate genes for controlling anthocyanin biosynthesis by transcriptome data and bioinformatics analysis. The effect of anthocyanin accumulations after cotransformation of PyWRKY31 or PyWRKY26 with its partners PyMYB10, PyMYB114, and PybHLH3 was verified in tobacco leaves and strawberry receptacles by a transient expression system. RT-qPCR analysis and a dual-luciferase reporter system further confirmed that this cotransformation activated the expression of PyDFR, PyANS, and PyUFGT in anthocyanin biosynthesis and PyGST in anthocyanin transport instead of the PyABC transporter and PyAVP. Furthermore, the cotransformed PyWRKY26 and PybHLH3 could bind to the PyMYB114 promoter, and PyWRKY26 directly activated the transcription of PyMYB114. In addition, the TF PyWRKY26 could interact with PybHLH3, as confirmed by firefly luciferase complementation and yeast two-hybrid (Y2H) assays. These results showed that the interaction of PyWRKY26 and PybHLH3 could cotarget the PyMYB114 promoter, which resulted in anthocyanin accumulation in red-skinned pear. This study further strengthened the understanding of the regulatory mechanism of anthocyanin accumulation and contributed to improving the appearance of red-skinned pears.