| Capsaicinoids are substances unique to Solanaceae vegetable peppers and have been widely used in various fields.At present,the demand for capsaicinoids in the market is increasing.Therefore,how to effectively regulate the synthesis of capsaicinoids to maximize the production of capsaicinoids is of great significance.At the same time,it also has important value in the study of the regulatory mechanism of capsaicinoid synthesis pathways.In this study,we used Hainan Yellow Lantern Chili as the material,with the drought and salicylic acid treatment,take the pepper fruit 40 days after flowering as the material for transcriptome sequencing analysis.The main findings are as follows:(1)Effects of drought and SA treatments on Yellow Lantern ChiliThe contents of capsaicinoids in the fruit of 40 days after anthesis in Yellow Lantern Chili under drought and salicylic acid treatment increased by about 45%and 71%,respectively,compared to the control.Under the conditions of drought and salicylic acid treatment,the REC(relative conductivity),free Pro(proline)content,SOD(superoxide dismutase)and POD(peroxidase)enzyme activities in pepper leaves significantly improved over the control.(2)Screening and analysis of differentially expressed genesThe transcriptome sequencing results were screened for differentially expressed genes,and a total of 2683 genes that were significantly differently expressed were found.339 differentially expressed genes were further screened by GO functional annotation and KEGG pathway enrichment analysis.There were 90 genes that were co-expressed and up-regulated in drought and salicylic acid treatments,and 217 genes were commonly down-regulated.There were 26 genes down-regulated in the CS group and down-regulated in the CD group,and 6 genes down-regulated in the CD group and down-regulated in the CS group.In addition,110 transcription factors,including MYB,bHLH,bZIP,NAC,WRKY,and AP2/ERF transcription factor family members,were identified from the differentially expressed genes during the 40-day drought and salicylic acid treatment of yellow capsicum fruits.(3)Bioinformatics analysis of sequencing dataWe used the Cufflinks software to predict and obtained 15774 new transcripts,furthermore,with the help of Astalavista software counting the gene models predicted by Cufflinks.We found many alternative splicing events,in which A3SS had the highest number.In addition,1693119 SNPs were detected in six sequenced samples by SNP and Indel detection and annotation,and the homozygous and heterozygous sites were 1638208 and 53111,respectively.(4)Analysis of regulation mechanism of capsaicin synthesis pathway based on transcriptome sequencingBased on sequencing data screening analysis,a total of 307 differentially expressed genes related to changes in capsaicin content were obtained,namely genes related to the spicy taste of Yellow Lantern Chili,and 90 of them had a direct effect on the accumulation of capsaicin content,217 of them has a reverse regulation effect on the synthesis and accumulation of capsaicin.In addition,the 110 transcription factors identified through analysis may regulate the synthesis pathway of capsaicin.(5)qRT-PCR validationReal-time fluorescence quantitative PCR was used to verify the expression trend of the co-responsive expression genes of selected 16 droughts and salicylic acid.The results showed that the expression tendency of differentially expressed genes is consistent between the sequencing results and the qRT-PCR validation results and proved that the transcriptome sequencing results were reliable.Therefore,the results can be used for subsequent analysis. |
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