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Article|01 Dec 2019|OPEN
The involvement of PybZIPa in light-induced anthocyanin accumulation via the activation of PyUFGT through binding to tandem G-boxes in its promoter
Hainan Liu1 , Jun Su2 , Yangfan Zhu1 , Gaifang Yao1 , Andrew C. Allan3,4 , Charles Ampomah-Dwamena3 , Qun Shu2 , Kui Lin-Wang3 and Shaoling Zhang1 , Jun Wu,1 ,
1Centre of Pear Engineering Technology Research, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 210095 Nanjing, China
2Institute of Horticulture, Yunnan Academy of Agricultural Sciences, 650205 Kunming, China
3The New Zealand Institute for Plant & Food Research Limited, Auckland, New Zealand
4School of Biological Sciences, University of Auckland, Auckland, New Zealand
*Corresponding author. E-mail: wujun@njau.edu.cn

Horticulture Research 6,
Article number: 134 (2019)
doi: https://doi.org/10.1038/s41438-019-0217-4
Views: 1047

Received: 29 Mar 2019
Revised: 08 Oct 2019
Accepted: 23 Nov 2019
Published online: 01 Dec 2019

Abstract

To gain insight into how anthocyanin biosynthesis is controlled by light in fruit, transcriptome and metabolome analyses were performed in the Chinese sand pear cultivar “Mantianhong” (Pyrus pyrifolia) after bagging and bag removal. We investigated transcriptional and metabolic changes and gene-metabolite correlation networks. Correlation tests of anthocyanin content and transcriptional changes revealed that 1,530 transcripts were strongly correlated with 15 anthocyanin derivatives (R2 > 0.9, P-value < 0.05), with the top 130 transcripts categorized as being associated with flavonoid metabolism, transcriptional regulation, and light signaling. The connection network revealed a new photosensitive transcription factor, PybZIPa, that might play an important role during light-induced anthocyanin accumulation. The overexpression of PybZIPa promoted anthocyanin accumulation in pear and strawberry fruit as well as tobacco leaves. Dual luciferase and Y1H assays further verified that PybZIPa directly activated the expression of PyUFGT by binding to tandem G-box motifs in the promoter, which was key to differential anthocyanin accumulation in debagged pear skin, and the number of G-box motifs affected the transcriptional activation of PyUFGT by PybZIPa. The results indicate that the light-induced anthocyanin biosynthesis regulatory mechanism in pear differs from that described in previous reports suggesting that a bZIP family member co-regulates anthocyanin biosynthesis with other transcription factors in apple and Arabidopsis. It was found that, in response to light, PybZIPa promoted anthocyanin biosynthesis by regulating important transcription factors (PyMYB114, PyMYB10, and PyBBX22) as well as structural genes (PyUFGT) via binding to G-boxes within promoters. This activation was amplified by the self-binding of PybZIPa to activate its own promoter. Overall, we demonstrate the utility of a multiomics integrative approach for discovering new functional genes and pathways underlying light-induced anthocyanin biosynthesis.