Correlation Analysis Of Co-Like Homologous Genes And Flowering And Dormancy In Platanus Acerifolia

Flowering and dormancy regulation share some elements in the transmission of signaling pathways,and research based on their commonality will be the future development trend.FT and its homologous genes have been shown to play an equally important role in plant flowering induction and annual growth regulation.The molecular mechanism of FT regulatory pathway in flower induction has been studied in depth,but there are relatively few studies on dormancy regulation.At present,the research on the dormancy regulation of Platanus acerifolia is only in the determination of different physiological indicators.The research on the molecular regulation mechanism has not been reported.Therefore,the study of the shared elements in this pathway will help to further reveal the molecular pathways of the flowering,shorten the process of cultivating the fruitless Platanus acerifolia and provide new evidence for the dormancy regulation theory of perennial deciduous plants.The research results can guide the molecular breeding strategy to the annual growth rhythm regulation of perennial ornamental plants such as Platanus acerifolia,which greatly improved the value of its garden application.CO is the directly upstream transcription factor of FT gene in FT regulatory pathway in Arabidopsis,so we studied the homologous genes of the CO,COL family in Platanus acerifolia.The main results are as follows:1.All PaCO-Like sequences with varying expression were screened from the transcriptome database of different dormancy stages(dormant induction,maintain and release)of the subpetiolar buds,after further comparison,9 of them were identified.According to the results of sequence alignment and phylogenetic analysis,they were named PaCOL5-1,PaCOL5-2,PaCOL13-1,PaCOL13-2,PaCOL14-1,PaCOL14-2,PaCOL6-1,PaCOL16-2,PaCOL6-3.2.Through the environmental factor regulation experiment and the expression pattern analysis in the subpetiolar buds under different dormancy stages,the correlation between the 9 genes and the two PaCO-Like cloned by research group member and the regulation of flowering and dormancy were explored.The results showed that PaCOL13-1 and PaFT had very consistent expression trends in different stages ofdormancy and different stages of flower bud differentiation,and combined with existing reports in model plants,it was speculated that it might be an upstream regulatory factor of PaFT;PaCOL16 gene can respond to low temperature induction and the expression level of PaCOL16-3 is decreasing during flower bud differentiation,which may be inhibitor.So PaCOL13 and PaCOL16 as the key genes for further research.The expression level of PaCOL5 in the different stages of dormancy changed regularly,but it was not related to the expression of PaFT.It may not participate in the PaFT regulatory pathway,and the expression of PaCOL14 was irregular,so they were not studied in depth.3.By analyzing the expression levels of PaCOL13 and PaCOL16 in different tissues,it was found that these genes were mainly expressed in the cotyledons and leaves of two leaves stages of Platanus acerifolia,and expressed in the leaves and stems of 10 leaves and adult plants.The circadian rhythm analysis showed that PaCOL13-1,PaCOL13-2 and PaCOL16-1 had obvious rhythm under long-day conditions,and the expression increased at the beginning of days,peaking at 12 h,16h and 16 h after light,and then entering the dark environment,the expression level began to decrease and reached the lowest at the end of darkness.The expression of PaCOL16-2 and PaCOL16-3 had no obvious regularity.There is no regularity under short day conditions.4.Construct overexpression vectors and transform tobacco and identify the phenotype of positive plants.The results showed that 35S: PaCOL13-2,35S: PaCOL16-2overexpressed plants showed late flower phenotype,35S: PaCOL13-1 over-expressed plant branches increased significantly,and 2 out of 35S: PaCOL16-1 overexpressing plants showed white flower traits,The construction of the 35S: PaCOL16-3 vector was completed late,and the positive plants have not yet flowered.The promoter sequences of these five genes were cloned for cis-acting element analysis,and the lengths were 2823 bp pPaCOL13-1,1905 bp pPaCOL13-2,1609 bp pPaCOL16-1,2231 bp pPaCOL16-2 and2417 bp pPaCOL16-3,respectively.Including the core promoter components TATA-box and CAAT-box and a large number of response components such as low temperature,light,circadian rhythm,hormones.The yeast one-hybrid vector was constructed separately,and the interaction relationship between these five genes and PaFT was analyzed.The results showed that these five genes did not directly interact with thepromoter fragment of PaFT.