| Rose(Rosa sp.),a traditional famous flower in China,is also an important ornamental flower in the world.Modern roses are developed by crossing and backcrossing within several species of Rosa genus.While most wild species of Rosa only have single round five petals,modern roses have various flower types due to the variation of petal numbers.But the research of rose flower develoment model is still uncompleted.So in this research,using RT-RCR and RACE strategy,genes related to flower development were cloned from R.chinensis 'Semperflorens';the corresponding proteins' subcellular localization were studied;their expression patterns were analyzed by Real-time PCR;their functions were verified by transformed into wild-type Arabidopsis using flower organ infection method.The main results are listed as follows:(1)The cDNA complete length of the two genes and the DNA full length of RcAP2 were obtained.The open reading frame of RcAP1 is 744 bp,encoding a protein of 247 amino acids.The RcAP2 cDNA sequence is 2236 bp,encoding a protein of 535 amino acids.5'-end noncoding region is 365 bp and 3'-end noncoding region is 263 bp.The DNA full length of RcAP2 contains ten exons and nine introns.(2)The plant expression vectors of RcAP1 and RcAP2 were constructed.Subcellular localization results showed that,RcAP1 and RcAP2 both produced fluorescence mainly in the nucleus,consistent with its transcription factor characteristics.(3)Both of the two genes were up-regulated during the early stages of flower bud differentiation.Among the whole flower development process,the highest expression level appeared in small mature flower bud.And in the middle and late stages of flower development,the two genes were tissue-specific expressed.RcAP1 was mainly expressed in sepals.RcAP2 was mainly expressed in sepals and petals,and the expression peak appeared in petals.The expression of RcAP2 was different in petals with different degree of stamen petalody and different rose cuitivars with different petal numbers.(4)The phenotypic analysis of wild-type Arabidopsis thaliana overexpressing RcAP1 and RcAP2 showed that the RcAP1 transgenic plants had the characteristics of early flowering,inflorescence transformation,number variation of petals and stamens.RcAP1 transgenic plants changed in the number and morphology of stamens.Combined the Real-time PCR results and model plant function validation results,it is suggested that the API homologous gene RcAP1 has the function of changing the inflorescence meristem to the flower meristem and regulating the development of the sepals.RcAP2 has the function of participating in the flower meristem and perianth characteristics establishment.Both of them may involve in the regulation of C class gene spatiotemporal activity.These results suggested that RcAP1 and RcAP2 are related to the process of stamen petalody.In this study,two class A genes,RcAP1 and RcAP2,related to flower organ development of rose,were characterized,and functions of them in flower development were studied.These results improved the flower development model of rose and explained the molecular mechanism of doubleflower in roses,which also laid the theoretical foundation for the rose flower pattern molecular breeding. |
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