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, Guangdong, 510642, P. R. China.
French Associates Institute for Agriculture and Biotechnology of Drylands, The J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Beersheba, Israel.
BMC Plant Biol. 2020 Sep 22;20(1):437. doi: 10.1186/s12870-020-02622-x.
MicroRNAs (miRNAs) and their regulatory functions in anthocyanin, carotenoid, and chlorophyll accumulation have been extensively characterized in many plant species. However, the miRNA regulatory mechanism in betalain biosynthesis remains mostly unknown.
In this study, 126 conserved miRNAs and 41 novel miRNAs were first isolated from Hylocereus monacanthus, among which 95 conserved miRNAs belonged to 53 miRNA families. Thirty-four candidate miRNAs related to betalain biosynthesis were differentially expressed. The expression patterns of those differential expressed miRNAs were analyzed in various pitaya tissues by RT-qPCR. A significantly negative correlation was detected between the expression levels of half those miRNAs and corresponding target genes. Target genes of miRNAs i.e. Hmo-miR157b-HmSPL6-like, Hmo-miR160a-Hpcyt P450-like3, Hmo-miR6020-HmCYP71A8-like, Hmo-novel-2-HmCYP83B1-like, Hmo-novel-15-HmTPST-like, Hmo-miR828a-HmTT2-like, Hmo-miR858-HmMYB12-like, Hmo-miR858-HmMYBC1-like and Hmo-miR858-HmMYB2-like were verified by 5'RACE and transient expression system in tobacco.
Hmo-miR157b, Hmo-miR160a, Hmo-miR6020 Hmo-novel-2, Hmo-novel-15, Hmo-miR828a and Hmo-miR858 play important roles in pitaya fruit coloration and betalain accumulation. Our findings provide new insights into the roles of miRNAs and their target genes of regulatory functions involved in betalain biosynthesis of pitaya.
在许多植物物种中，microRNAs（miRNAs）及其在花色苷、类胡萝卜素和叶绿素积累中的调控功能已得到广泛研究。然而，甜菜红素生物合成中的 miRNA 调控机制在很大程度上仍不清楚。
本研究首次从人心果中分离出 126 个保守 miRNAs 和 41 个新的 miRNAs，其中 95 个保守 miRNAs 属于 53 个 miRNA 家族。34 个与甜菜红素生物合成相关的候选 miRNA 表达差异。通过 RT-qPCR 分析了这些差异表达 miRNA 在各种火龙果组织中的表达模式。检测到其中一半 miRNA 的表达水平与相应靶基因之间存在显著负相关。miRNA 的靶基因，即 Hmo-miR157b-HmSPL6-like、Hmo-miR160a-Hpcyt P450-like3、Hmo-miR6020-HmCYP71A8-like、Hmo-novel-2-HmCYP83B1-like、Hmo-novel-15-HmTPST-like、Hmo-miR828a-HmTT2-like、Hmo-miR858-HmMYB12-like、Hmo-miR858-HmMYBC1-like 和 Hmo-miR858-HmMYB2-like，通过 5'RACE 和瞬时表达系统在烟草中得到验证。
Hmo-miR157b、Hmo-miR160a、Hmo-miR6020、Hmo-novel-2、Hmo-novel-15、Hmo-miR828a 和 Hmo-miR858 在火龙果果实着色和甜菜红素积累中发挥重要作用。我们的研究结果为 miRNA 及其靶基因在火龙果甜菜红素生物合成中的调控功能提供了新的见解。
