The technical innovation team of the tropical ornamental plant industry of the Chinese Academy of Tropical Agricultural Sciences has made new progress in the research on the flower color formation and regulation mechanism of Dendrobium autumnale and the development of flower color regulation technology. The team excavated the key genes that regulate the anthocyanin synthesis in the flowers of Dendrobium autumnale, established a technical system based on VIGS to rapidly study the function of genes related to the flower organs of Dendrobium autumnale, and used it to successfully regulate the flower color of commercial flowers. It provides technical support for mining functional genes related to flower development, flower color, flower fragrance and senescence of Dendrobium autumnale, as well as developing commodity of polychrome Dendrobium autumnale.
Dendrobium autumnale (Phalaenopsis type Dendrobium) is the most potential tropical orchid after Phalaenopsis and Cymbidium hybridum. Hainan is the only suitable place for large-scale production of Dendrobium autumnale in China. Due to the limitation of germplasm resources, the flower color of Dendrobium autumnale on the domestic market is mainly purplish red, and the coloring mode is single. It has a good market prospect to create a new variety of double colored Dendrobium autumnale that makes people "bright". However, the mechanism of flower color formation and regulation of Dendrobium autumnale is still unclear.
The research team has discovered two transcription factor genes DhMYB2 and DhbHLH1 that are closely related to the accumulation of anthocyanins in the petals of Dendrobium autumnale. The two transcription factors interact to regulate the synthesis of anthocyanins. It laid a foundation for analyzing the mechanism of flower color regulation and molecular breeding for flower color improvement of Dendrobium autumnale. Relevant research was published in Plant Physiology and Biochemistry. Researcher Yin Junmei, the team leader, is the corresponding author of the paper, and researcher Li Chonghui, the team member, is the first author. The research was supported by the National Natural Science Foundation of China and major scientific and technological projects of Hainan Province.
On this basis, the research team has recently successfully suppressed the expression of DhMYB2 in Dendrobium autumnale using VIGS technology with DhMYB2 as the target gene, resulting in a phenotype of reduced or missing anthocyanin content in petals, sepals and lips. It is further confirmed that DhMYB2 is a key gene regulating anthocyanin synthesis in the above tissues. The research shows that the 123 bp region starting from the DhMYB2 initial codon can be used as the VIGS insertion fragment, which can efficiently silence DhMYB2 and produce a very obvious pattern change phenotype. This gene fragment can be connected with the target gene fragment in series and developed into a visual VIGS marker, which is widely used in the research of gene function related to flower organs of Dendrobium autumnale.
Functional research of DhMYB2 and development of VIGS technology
The above research was published on the Scientific Horticulture under the title of "Virus induced gene silencing (VIGS) for functional analysis of genes involved in the regulation of anthropology biosynthesis in the personality of Philadelphia type Dendrobium hybrids". Researcher Yin Junmei, the leader of the team, and researcher Li Chonghui, the team member, are the co corresponding authors of the paper, and Hou Tianze, a postgraduate of Hainan University, is the first author. The research was supported by the national key research and development program, the high-level talent project of Hainan Natural Science Foundation, and the project led by the Chinese Academy of Tropical Agricultural Sciences.
In addition, the team used the above research results to instantly color several commercial Dendrobium autumnale. After treatment, the flowers in the same inflorescence changed color continuously, and the effect lasted until the whole flower withered. The performance of different plants and flowers is different, and the ornamental value is greatly improved. This method has applied for the national invention patent (application No. 202111682443. X), and has a good commercial application prospect.
Using VIGS technology to color Dendrobium autumnale
