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Ixora chinensis Lam. is a widespread tropical woody ornamental plant for its abundant and bright flowers. In this study, we established a regeneration system of I. chinensis for the first time using young leaves as explants on the Murashige and Skoog (MS) medium supplemented with different Plant Growth Regulators (PGRs). The optimal conditions for shoot regeneration include 4.0 mg/L 6-Benzylaminopurine (6-BA), 1.0 mg/L Thidiazuron (TDZ) and 1.0 mg/L α-Naphthalene acetic acid (NAA) with a shoot regeneration rate of 23.7%. Subculture of shoots on MS medium fortified with 1.0 mg/L 6-BA and 0.5 mg/L NAA achieved a survival ratio of 80.8% and rooting ratio of 30.5%. This result will be helpful in gene biotechnology to develop more colorful or fragrant flowers of I. chinensis in the future. This study is the first report to establish a regeneration system for Ixora chinensis.

Phalaenopsis cultivar &lsquo, Panda&rsquo, is a beautiful and valuable ornamental for its big flower and unique big spots on the petals and sepals. Although anthocyanins are known as the main pigments responsible for flower colors in Phalaenopsis, and the anthocyanins biosynthetic pathway in Phalaenopsis is generally well known, the detailed knowledge of anthocynins regulation within the spot and non-spot parts in &lsquo, flower is limited. In this study, transcriptome and small RNA libraries analysis from spot and non-spot sepal tissues of &lsquo, were performed, and we found PeMYB7, PeMYB11, and miR156g, miR858 is associated with the purple spot patterning in its sepals. Transcriptome analyses showed a total 674 differentially expressed genes (DEGs), with 424 downregulated and 250 upregulated (Non-spot-VS-Spot), and 10 candidate DEGs involved in anthocyanin biosynthetic pathway. The qPCR analysis confirmed that seven candidate structure genes (PeANS, PeF3&prime, H, PeC4H, PeF3H, PeF3H1, Pe4CL2, and PeCHI) have significantly higher expressing levels in spot tissues than non-spot tissues. A total 1552 differentially expressed miRNAs (DEMs) were detected with 676 downregulated and 876 upregulated. However, microRNA data showed no DEMs targeting on anthocyanin biosynthesis structure gene, while a total 40 DEMs target transcription factor (TF) genes, which expressed significantly different level in spot via non-spot sepal, including 2 key MYB regulator genes. These results indicated that the lack of anthocyanidins in non-spot sepal may not directly be caused by microRNA suppressing anthocyanidin synthesis genes rather than the MYB genes. Our findings will help in understanding the role of miRNA molecular mechanisms in the spot formation pattern of Phalaenopsis, and would be useful to provide a reference to similar research in other species.