| The flowers is one of the most important innovative organs of angiosperms,at the same time the color of flowers is one of the most adaptive phenotype in plant evolution history.For example,different pollinators could distinguish the variety of colors so the flowers' color has important influence on the improvement of outcrossing rate and adaptation of angiosperms in environment.Aquilegia yabeana is endemic to China,within the species,the flowers of most populations are purple,except one variant of this species distributed in Longmen Mountain,Suizhong County,Liaoning Province named Aquilegia yabeana f.luteola,whose sepals and petals are light yellow,and the color of the flowers is stable,there is no color variation or transition in the population.According to the previous work,the genetic background of all the natural populations in A.yabeana is similar,and they have the recent common ancestor.So the color variation has been fixed in Liaoning,which makes it a good model in studying the evolution and molecular mechanism of color variation in angiosperms.In this work,three populations with two different colors of A.yabeana were chosen to be focused:purple flowers(BJ01,NM01)and yellow flowers(LN01).Based on the measurement of phytochemicals,comparative analysis of transcriptomics and genetic diversity detection,the molecular mechanism of flower color variation among these wild populations was analyzed.The main results and conclusions are as follows:Firstly,qualitative and quantitative analysis by HPLC showed that the purple phytochemicals of the A.yabeana was cyaniding,and the yellow phytochemicals of yellow flower was myricetin.Secondly,based on the analysis of transcriptome,it was found that among all of the genes expressed differentially at the genomic level,21 genes encode enzymes related to anthocyanidin synthesis,involving five biosynthetic pathways;the metabolic pathways in the two colors of flowers present changes in the expression of multiple enzymes rather than any single enzyme,suggesting that flower color variation is likely to be caused by mutation in upstream regulatory genes,or feedback regulation of metabolism.Combined with the results of Realtime qRT-PCR,the expression levels of PAL,F3H,ANS,DFR,BZ1,F3 'HI and F3'H2 related to the synthesis of cyanidin were significantly higher in purple flowers than in yellow flowers;the expression of the synthetic myricetin-related F3 '5 'H and synthetic carotenoid-related crtB were significantly higher in the yellow flower than in the purple flower.Both Transcriptome data and qRT-PCR results showed that two transcription factors,AyMYB-3 and AybHLH-1 expressed significantly higher in purple flower perianth tablets than in yellow flowers.The promoters of seven highly expressed syntheases of the anthocyanin biosynthesis metabolic pathway in purple flowerare are rich in recognition sites of MYB and bHLH transcription factors.It is speculated that the divergent express level of these two transcription factors may be the key points for the natural variation of flower color in the A.yabeana.At the same time,the sequence genetic diversity analysis of the key synthase genes revealed that the mutation of Asp to Tyr at position 142 of F3H2 will be used as a candidate site for the VIGS gene silencing analysis to further determine its influence on flower color.This work focused the differentiation of flower color in wild populations of A.yabeana.The pigments related to the color variation,the nine key synthetase genes involved in the regulation of pigment biosynthesis in plants and two transcription factors were initially identified,it lays a good foundation to further explore the molecular and genetic mechanism of the flower color variation in different wild populations of A.yabeana. |
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