Wang Fang, Liu Liang, Yu Rangcai, Li Xin, Yu Yunyi, Li Xinyue, Yue Yuechong, Fan Yanping
The Research Center for Ornamental Plants, College of Horticulture, South China Agricultural University, Guangzhou, 510642, China.
College of Life Sciences, South China Agricultural University, Guangzhou, 510642, China.
BMC Genomics. 2025 Apr 30;26(1):430. doi: 10.1186/s12864-025-11583-0.
Hedychium coronarium is highly valued for its intense fragrance, which may be influenced by the expression of microRNAs (miRNAs). miRNAs are a class of small RNAs that play conserved and pivotal regulatory roles throughout plant growth and development, modulating various aspects of plant metabolism. However, the specific roles of miRNAs in the growth and development of H. coronarium remain largely uncharacterized.
To identify miRNAs in H. coronarium and assess their potential role in the synthesis of floral fragrance compounds, we analyzed the volatile compounds and miRNA expression patterns at three developmental stages (F1, F5, F6). Our findings revealed that the volatile emissions of major floral compounds, including eucalyptol, ocimene, and linalool, increased as the flowers progressed through development. Small RNA sequencing identified 171 conserved miRNAs from 24 miRNA families, along with 32 novel miRNAs. Degradome sequencing uncovered 102 mRNA degradation sites corresponding to 90 target genes from 30 miRNA families. Quantitative RT-PCR (qRT-PCR) analysis showed that the expression of hco-miR393a and hco-miR167n mirrored the release pattern of floral fragrance compounds, while the expression of HcTIR1 and HcARF8 inversely correlated with those of hco-miR393a and hco-miR167n. Co-transformation experiments in tobacco confirmed that HcTIR1 and HcARF8 are direct targets of hco-miR393a and hco-miR167n, respectively. Additionally, treatments with exogenous IAA and the auxin inhibitor PCIB modulated both the release of floral volatiles and the expression of hco-miR393a and hco-miR167n. STTM and VIGS experiments further indicated that hco-miR167n and hco-miR393a positively regulate floral fragrance metabolism, while HcARF8 and HcTIR1 act as negative regulators. Finally, dual-luciferase and yeast one-hybrid assays demonstrated that HcARF8 binds to the promoter of the terpene synthase gene HcTPS8, thereby regulating the biosynthesis of floral fragrance compounds.
This study represents the first comprehensive identification of miRNAs in H. coronarium and the characterization of their expression profiles in petal tissues at various developmental stages. These findings offer novel insights into the molecular mechanisms governing the synthesis of floral fragrance compounds and highlight the critical role of miRNAs in the regulation of metabolic processes within the Zingiberaceae family.
姜花因其浓郁的香气而备受珍视，其香气可能受微小RNA（miRNA）表达的影响。miRNA是一类小RNA，在植物的整个生长发育过程中发挥着保守且关键的调控作用，调节植物代谢的各个方面。然而，miRNA在姜花生长发育中的具体作用在很大程度上仍未明确。
为了鉴定姜花中的miRNA并评估它们在花香化合物合成中的潜在作用，我们分析了三个发育阶段（F1、F5、F6）的挥发性化合物和miRNA表达模式。我们的研究结果表明，随着花朵发育，主要花香化合物（包括桉叶素、罗勒烯和芳樟醇）的挥发性排放增加。小RNA测序从24个miRNA家族中鉴定出171个保守miRNA，以及32个新的miRNA。降解组测序发现了102个与来自30个miRNA家族的90个靶基因相对应的mRNA降解位点。定量逆转录聚合酶链反应（qRT-PCR）分析表明，hco-miR393a和hco-miR167n的表达反映了花香化合物的释放模式，而HcTIR1和HcARF8的表达与hco-miR393a和hco-miR167n的表达呈负相关。烟草中的共转化实验证实，HcTIR1和HcARF8分别是hco-miR393a和hco-miR167n的直接靶标。此外，用外源吲哚乙酸（IAA）和生长素抑制剂PCIB处理可调节花香挥发物的释放以及hco-miR393a和hco-miR167n的表达。STTM和VIGS实验进一步表明，hco-miR167n和hco-miR393a正向调节花香代谢，而HcARF8和HcTIR1则作为负调节因子。最后，双荧光素酶和酵母单杂交试验表明，HcARF8与萜烯合酶基因HcTPS8的启动子结合，从而调节花香化合物的生物合成。
本研究首次全面鉴定了姜花中的miRNA，并表征了它们在不同发育阶段花瓣组织中的表达谱。这些发现为花香化合物合成的分子机制提供了新的见解，并突出了miRNA在姜科植物代谢过程调控中的关键作用。
