Preliminary Functional Study Of The DELLA Protein CbuGRAS9 In Regulating The Flowering Of Catalpa Bungei

Flowering transition is a complex process in the life history of plants,a key developmental process from vegetative growth to reproductive growth.The gibberellin pathway is one of the main regulatory pathways of flowering,and some transcription factors involved in gibberellin signal transduction have been identified,among which DELLA protein is the key protein in the gibberellin pathway,which has an important regulatory effect on the flowering transition of forest trees.During the process of flowering transition,DELLA protein inhibits the expression of a series of flower bud-inducing genes,thereby regulating the flowering of forest trees.Exploring the function of DELLA protein in Catalpa bungei will help to further reveal the flowering regulation mechanism of woody plants.In this study,by comparing the DELLA gene in Arabidopsis thaliana,five DELLA gene homologous genes of Catalpa bungei were screened,and the expression pattern and biological function of the expression pattern and biological function were preliminarily studied,and the function of DELLA protein in the process of flowering transformation of Bairihua Catalpa bungei was preliminarily verified,and the main results are as follows :(1)Using comparative genomics,homologous genes of 5 Arabidopsis thaliana DELLA genes were identified in the Catalpa bungei genome.Bioinformatics analysis showed that these five DELLA proteins contained DELLA and GRAS conserved domains;The tissue-specific expression analysis of five DELLA genes showed that the DELLA gene was mainly expressed in the top buds and young leaves of the Catalpa bungei,and the expression was relatively low in other parts.In addition to Cbu GRAS2,the expression of DELLA gene in Bairihua Catalpa bungei was higher than that in 9-1 Catalpa bungei,among which the DELLA gene with the largest expression difference was Cbu GRAS9.(2)The results of subcellular localization experiments showed that the green fluorescence signal of Cbu GRAS9-GFP was in the nucleus,indicating that the DELLA protein of Catalpa bungei was localized to the nucleus.(3)After overexpression of Cbu GRAS9 in Arabidopsis thaliana,transgenic plants exhibit phenotypes such as increased number of rosette leaves,delayed flowering time,and reduced plant height compared to wild-type Arabidopsis thaliana.The results indicate that the Cbu GRAS9 gene is involved in regulating the number of rosette leaves,flowering time,and plant height in Arabidopsis thaliana.(4)Through yeast two-hybrid sieve library experiments,high-throughput sequencing of the screened positive clonal amplification products was performed,and 2392 genes were screened,including 104 transcription factors.To further explore the function of the 2392 genes screened,GO and KEGG enrichment analyses were performed on these genes.The results of GO analysis showed that at the level of biological process,the three items of metabolic process,cellular process and single-organism process were significantly enriched.At the level of cellular component,the two entries of cells and cell components are significantly enriched;At the molecular function level,the two items of binding and catalytic activity are significantly enriched.In KEGG enrichment analysis,gene enrichment pathways are mainly in metabolic pathways and biosynthesis of secondary metabolites.According to the results of GO and KEGG analysis,genes obtained through sieve banks may be related to metabolism.