State Key Laboratory for Conservation and Utilization of Subtropical Agrobioresources/Guangdong Provincial Key Laboratory of Postharvest Science of Fruits and Vegetables/Key Laboratory of Biology and Genetic Improvement of Horticultural Crops (South China), Ministry of Agriculture and Rural Affairs, College of Horticulture, South China Agricultural University, Guangzhou 510642, Guangdong, China.
Int J Mol Sci. 2021 Feb 22;22(4):2171. doi: 10.3390/ijms22042171.
Betalains are water-soluble nitrogen-containing pigments with multiple bioactivities. Pitaya is the only large-scale commercially grown fruit containing abundant betalains for consumers. However, the upstream regulators in betalain biosynthesis are still not clear. In this study, HmoWRKY40, a novel WRKY transcription factor, was obtained from the transcriptome data of pitaya (). HmoWRKY40 is a member of the Group IIa WRKY family, containing a conserved WRKY motif, and it is located in the nucleus. The betalain contents and expression levels of HmoWRKY40 increased rapidly during the coloration of pitaya and reached their maximums on the 23rd day after artificial pollination (DAAP). Yeast one-hybrid and transient expression assays showed that HmoWRKY40 could bind and activate the promoter of . Silencing the gene resulted in a significant reduction of betacyanin contents. These results indicate that HmoWRKY40 transcriptionally activates which is involved in the regulation of pitaya betalain biosynthesis. The results of the present study provide new regulatory networks related to betalain biosynthesis in pitaya.
甜菜碱是一类具有多种生物活性的水溶性含氮色素。火龙果是唯一一种含有丰富甜菜碱供消费者食用的大规模商业化种植的水果。然而，甜菜碱生物合成的上游调控因子仍不清楚。本研究从火龙果转录组数据中获得了一个新的 WRKY 转录因子 HmoWRKY40()。HmoWRKY40 是 IIa 组 WRKY 家族的成员，含有一个保守的 WRKY 基序，位于细胞核中。在火龙果的着色过程中，甜菜碱含量和 HmoWRKY40 的表达水平迅速增加，并在人工授粉后 23 天（DAAP）达到最大值。酵母单杂交和瞬时表达分析表明，HmoWRKY40 可以结合并激活 的启动子。沉默 基因导致甜菜红素含量显著降低。这些结果表明，HmoWRKY40 转录激活 ，参与调节火龙果甜菜碱生物合成。本研究结果为火龙果甜菜碱生物合成提供了新的调控网络。
