| Gerbera hybrida is an herbaceous perennial flower,which belongs to the Asteraceae family.The inflorescence of Gerbera hybrida are composed of three different types of flowers: rays,trans,discs,which are tightly packed into a condensed,radially organized flower head(capitulum).The three types of flowers were divided into three types: single,semi-double and double-flowered,depending on the length of trans flower and whether or not.In this study,we used semi-double and double flower mutants of ’Fenxiu’ Gerbera as the research object and selected four periods that could represent flower development.In order to explore the molecular mechanism of GhGDEF3 in the elongation of double-flowered gerbera transitional flowers,from phenotypic comparative analysis,protein interactions,temporal and spatial expression characteristics,and virus silencing and Heterologous transformation Arabidopsis experiment.We hope we can provide some theoretical evidences for the study of gerbera in flower type.The main results are as follows: 1.Through observation and analysis of the flowers and petals in the double and semi-double flower mutants ’Fenxiu’ Gerbera,it was found that in the number of petals,the two types of flowers are similar in the ray flowers,in the trans flowers is the double flowers more than the semi-double flowers,in the disc flowers just opposite to trans flowers,but the two types of flowers in the total number of petals are similar.Compared with the semi-double flower type,the double-flower gerbera has a small staminate structure in which the stamen is not fully degraded at the edge of the central disc flowers.The more declining the stamen of this floret,the closer its size is to trans flowers,the longer the length of the trans flowers,and the deeper the flowers.2.Phylogenetic tree and amino acid sequence analysis showed that GhGDEF3 belong to the evolutionary branch of euAP3.3.Construction of Yeast two-hybrid bait bector and capture vector of Gerbera jamesonii B function genes for protein interaction.The results show that GhGDEF3 interact with GhGGLO1 gene,and does not interact with GhGDEF1 and GhGDEF2.4.Using qRT-PCR technique to analyze expression characteristic of the GhGDEF3 from in semi-double and double flower.The results showed that GhGDEF3 was highly expressed in the trans flowers and low in the stamens.On the contrary,the expression of GhGDEF3 was high in stamens and low in trans flowers in semi-double mutants.5.In order to explore the effect of virus silencing of GDEF3 gene in Gerbera,the VIGS vector of GDEF3 gene was constructed.It was used to transformed into Gerbera jamesonii flowers by Agrobacterium.The results showed that after the virus silenced the GhGDEF3 gene,the trans flower of the double flowered of Gerbera became shorter and turn into semi-double flower.In terms of gene expression,GhGDEF3 decreased by 37.91%,51.45%,39.89%,and 46.91%,respectively,and GhGGLO1 decreased by 38.91%,40.11%,19.79%,and 25.23%,respectively,in ray flowers,trans flowers,disc flowers,and stamens.6.An overexpression vector of GhGDEF3 gene was constructed and Arabidopsis was heterologously transformed to obtain 5 transgenic Arabidopsis plants.The petals of transgenic Arabidopsis were difficult to expand and their size was significantly shorter than that of the wild type.The expression of GhGDEF3 in the petals of the 5 transgenic lines was significantly higher than that of the wild type control,while the transgenic Arabidopsis own B gene AP3 and PI.The expression level was significantly down-regulated,indicating that co-suppression of AP3 and PI controlling petal growth occurred in transgenic Arabidopsis flowers,resulting in a decrease in petal growth in Arabidopsis thaliana. |
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