Functional Analysis of OfMYB12 Gene Involved in Flavonoid Synthesis in Osmanthus fragrans
ZHANG Hui-Lian, WANG Yi-Guang, ZHONG Shi-Wei, DENG Jin-Ping, FANG Qiu, ZHAO Hong-Bo*
College of Landscape Architecture and Architecture/Zhejiang Key Laboratory of Germplasm Innovation and Utilization of Landscape Plants/Key Laboratory of Germplasm Innovation and Utilization of Landscape Plants in Southern China, National Forestry and Grassland Administration, Zhejiang A&F University, Hangzhou 311300, China
Abstract MYB transcription factor is widely involved in plant growth and development, and plays an important role in regulating plant secondary metabolism. The OfMYB12 gene, which was related to flavonoid synthesis and screened by RNA-Seq technology in previous study of our research group, was further cloned from the flower buds of Osmanthus fragrans 'Yanhonggui'. The ORF length of OfMYB12 gene (GenBank No. WMD01176) was 1 026 bp and encoded 341 amino acids. The subcellular localization results indicated that this gene was located in the nucleus. Multiple sequence alignment and phylogenetic tree indicated that the OfMYB12 gene belonged to a typical R2R3 transcription factor and had the closest relationship with anthocyanin activator AtMYB56 in Arabidopsis thaliana. The analysis of tissue-specific results showed that OfMYB12 gene was expressed in different tissues of O. fragrans and had the highest expression level in petals. Heterologous overexpression of OfMYB12 in Petunia hybrida 'Mitchell' resulted in a significantly higher total flavonoid content in the transgenic petals compared to the control group (P<0.05), and the expression levels of related genes (PhCHS (P. hybrida chalcone synthase), PhF3H (P. hybrida flavanone 3-hydroxylase), PhFLS (P. hybrida flavonol synthase)) in the flavonoid synthesis pathway in transgenic petals were significantly increased. Based on the above results, it is speculated that the OfMYB12 gene might be involved in the regulation of flavonoid secondary metabolism biosynthesis. The results of this study provides a theoretical basis for exploring the molecular mechanism of flavonoid synthesis in Osmanthus and improving the quality of Osmanthus.
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