Hua Qingzhu, Zhou Qianjun, Gan Susheng, Wu Jingyu, Chen Canbin, Li Jiaqiang, Ye Yaoxiong, Zhao Jietang, Hu Guibing, Qin Yonghua
State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources/Key Laboratory of Biology and Genetic Improvement of Horticultural Crops-South China, Ministry of Agriculture, College of Horticulture, South China Agricultural University, Guangzhou 510642, China.
General Station of the Administration of Seeds Guangdong Province, Guangzhou 510500, China.
Int J Mol Sci. 2016 Sep 28;17(10):1606. doi: 10.3390/ijms17101606.
Red dragon fruit or red pitaya () is the only edible fruit that contains betalains. The color of betalains ranges from red and violet to yellow in plants. Betalains may also serve as an important component of health-promoting and disease-preventing functional food. Currently, the biosynthetic and regulatory pathways for betalain production remain to be fully deciphered. In this study, isobaric tags for relative and absolute quantitation (iTRAQ)-based proteomic analyses were used to reveal the molecular mechanism of betalain biosynthesis in fruits at white and red pulp stages, respectively. A total of 1946 proteins were identified as the differentially expressed between the two samples, and 936 of them were significantly highly expressed at the red pulp stage of . RNA-seq and iTRAQ analyses showed that some transcripts and proteins were positively correlated; they belonged to "phenylpropanoid biosynthesis", "tyrosine metabolism", "flavonoid biosynthesis", "ascorbate and aldarate metabolism", "betalains biosynthesis" and "anthocyanin biosynthesis". In betalains biosynthesis pathway, several proteins/enzymes such as polyphenol oxidase, CYP76AD3 and 4,5-dihydroxy-phenylalanine (DOPA) dioxygenase extradiol-like protein were identified. The present study provides a new insight into the molecular mechanism of the betalain biosynthesis at the posttranscriptional level.
红肉火龙果或红皮火龙果（）是唯一含有甜菜红素的可食用水果。在植物中，甜菜红素的颜色范围从红色、紫色到黄色。甜菜红素也可能是促进健康和预防疾病的功能性食品的重要成分。目前，甜菜红素生物合成和调控途径仍有待完全破译。在本研究中，分别使用基于相对和绝对定量的等压标签（iTRAQ）蛋白质组学分析来揭示红肉火龙果白肉和红肉阶段果实中甜菜红素生物合成的分子机制。总共鉴定出1946种蛋白质在两个样品之间差异表达，其中936种在红肉火龙果红肉阶段显著高表达。RNA测序和iTRAQ分析表明，一些转录本和蛋白质呈正相关；它们属于“苯丙烷生物合成”、“酪氨酸代谢”、“类黄酮生物合成”、“抗坏血酸和醛糖代谢”、“甜菜红素生物合成”和“花青素生物合成”。在甜菜红素生物合成途径中，鉴定出了几种蛋白质/酶，如多酚氧化酶、CYP76AD3和4,5-二羟基苯丙氨酸（DOPA）双加氧酶类外二醇蛋白。本研究为转录后水平上甜菜红素生物合成的分子机制提供了新的见解。
