LcNAC13 Physically Interacts with LcR1MYB1 to Coregulate Anthocyanin Biosynthesis-Related Genes during Litchi Fruit Ripening.

Guoxiang Jiang,Zhiwei Li,Sen Lin,Yunbo Song,Yueming Jiang,Riming Huang,Hong Zhu,Xuewu Duan

doi:10.3390/biom9040135

Abstract

Anthocyanin accumulation is crucial for the development of quality for most fruit. The mechanism underlying the regulation of anthocyanin biosynthesis by transcription factors in litchi fruit remains largely unknown. In this study, we isolated one NAC (NAM, ATAF1/2 and CUC2) TF gene, LcNAC13. Expression of LcNAC13 was upregulated as ripening proceeded, followed by the accumulation of anthocyanins. Electrophoretic mobility shift assay (EMSA) and transient expression assay showed that LcNAC13 could negatively regulate the expression of anthocyanin biosynthesis-related genes, including LcCHS1/2, LcCHI, LcF3H, LcF3’H, LcDFR, and LcMYB1. Furthermore, LcR1MYB1, as one R1-MYB type MYB, was identified to physically interact with LcNAC13 and reverse the effect of LcNAC13. Taken together, these results suggested that LcNAC13 and LcR1MYB1 may act together to antagonistically regulate anthocyanin biosynthesis during litchi fruit ripening, which helps to provide new insights into the regulatory networks of anthocyanin biosynthesis.

Highlights

Anthocyanins are a class of flavonoids with >250 members widely distributed in plants [1].Anthocyanins constitute the main pigments in flowers and fruits, resulting in the typical red, blue, purple, or black color characteristics, and contributing to the marketable quality of some vegetables and fruits [2,3]
LcNAC13 directly bound to the promoters of anthocyanin biosynthesis-related genes, including LcCHS1/2, LcCHI, LcF3H, LcF3’H, LcDFR and LcMYB1, and repressed their transcription, while LcR1MYB1 physically interacted with LcNAC13 and opposed the negative effect, suggesting that LcNAC13 and LcR1MYB1 might act together to regulate anthocyanin biosynthesis-related genes during litchi fruit ripening
The fruit growth and development were obviously divided into two Physiological Characteristics of Litchi Fruit during Ripening stages according to average fruit width (Figure 1B) and fruit weight (Figure 1C): a rapid growth

Summary

Introduction

Anthocyanins constitute the main pigments in flowers and fruits, resulting in the typical red, blue, purple, or black color characteristics, and contributing to the marketable quality of some vegetables and fruits [2,3]. Anthocyanins play important biological roles in the growth, development, and responses to the environmental stimuli in plants, endowing flowers and fruits with various colors to attract pollinators and seed distributors [4], and acting as antioxidants that scavenge reactive oxygen species (ROS) and function in pathogen defense responses [5,6,7,8]. The anthocyanin biosynthesis pathway has been studied extensively and genes involved in most of the biosynthetic steps have been characterized in various plants [12,13].

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Results

Discussion

Conclusion