关键词: MIXTA, R2R3 MYB结构域, MYB转录因子, 表皮细胞

Abstract: Nowadays, the morphology of epidermal cells in the angiospermaes is a universal biological phenomena, and it roughly includes the shape of the epidermal cells, the formation of epidermal cells attached derivatives, and the differentiation of trichomes and root-hair cells, etc.. Relying on large amounts of experimental results, people have found that the biological functions of MIXTA and its orthologous genes have these related phenomena. MIXTA encodes a MYB-like transcription factor with R2R3 domain. It got widespread attention since 1994 when MIXTA had been firstly reported in the Antirrhinum majus,and also got more in-depth studies and discussions in different species. It was found that MIXTA promoted the petals epidermal cells changed to be conical and made the petals inner epidermal cells have the velvet-like texture, on the contrary petals epidermal cells changed to flattening and the velvet-like texture in petals within epidemals disappeared when MIXTA gene had mutations in the wild type of Antirrhinum majus. Ectopic expression of MIXTA regulated the growth of the cone cells and multicellular glandular trichomes in different tissues. During the long-term study, some MIXTA homologous genes have been found in many other species except A. majus,collectively known as MIXTA-like, such as Thalictrum thalictroides, Erythranthe lewisii, Solanum lycopersicum, Arabidopsis thaliana,etc. especially in Arabidopsis thaliana. The functions of these genes in Arabidopsis thaliana were similar to MIXTA in Antirrhinum majus and research on their downstream genes regulating pathways were more clearly. At the same time, MIXTA, as a MYB-like transcription factor, however, could be through the interactions with bHLH transcription factors and WD40 transcription factor to indirectly control the synthesis of anthocyanin. MIXTA affects a series of biological characteristics, such as the surface temperature of the petals, smell, color, moisture, texture and optical properties. It also indirectly influenced plant pollination by changing the phenotypes of the plant petals and established their own defense systems. The biological functions of MIXTA are so extensive that studying it had an important biological significance. In this article, the basic structure of MIXTA gene was first briefly introduced, and using bioinformatics technology including the alignment of amino acid sequences and phylogenetic analysis to analyze the relationship between MIXTA and its orthologous proteins and R2R3 domain that they all had. After that, from three aspects including the shape of epidermal cells (turning to be conical), the formation of the affiliated derivatives on epidermis cells (including cuticular wax biosynthesis, trichomes and the differentiation of the root-hair cells), participating in hormone metabolic pathways to indirectly regulate the epidermal cells morphology to discuss the specific function of MIXTA and its homologous genes. Finally, the future of MIXTA application in agriculture, ornamental horticulture was discussed which will provide a reference for researchers in this field.

Key words: MIXTA gene')">