Mining Of Genes In Peony In Response To High Temperature Stress Based On Transcriptome Sequencing Technology

Peony(Paeonia suffruticosa)is an important traditional flower in my country.It is widely used in landscaping and has important economic,social and ecological value.Peony has poor heat tolerance,and the high temperature in summer limits the growth and ornamental quality of peony.In this study,Jiangnan peony ’Hu Hong’(Paeonia ostii ’Hu Hong’)was used as the research object.The mature leaves of peony were treated with high temperature stress,and related physiological indicators and transcriptome sequencing and analysis were performed to screen out the differences in response to high temperature stress in peony.express genes.The key genes involved in the heat-resistance mechanism of peony were mined through weighted co-expression network analysis,and the physiological and biochemical indexes of mature leaves of peony were further measured after high temperature stress,and the expression trends of various physiological indexes and related regulatory genes were integrated to analyze the mechanism of peony response to high temperature stress and the relationship between them.Mining candidate key genes provides a theoretical basis.The main findings are as follows:(1)The high temperature stress test on mature leaves of peony showed that the leaves showed significant phenotypic changes with the prolongation of high temperature stress time.With the loss of water and damage to the biofilm,the relative electrical conductivity of the leaves increased significantly,and the activities of antioxidant enzymes increased first and then decreased.Among the osmotic regulators,the content of proline increased the most with the prolongation of treatment time.It was clarified that free proline,relative conductivity and soluble protein were important indicators to measure the physiological mechanism changes of peony in response to high temperature stress.(2)Using the mature leaves of ’Huhong’ peony as material,the transcriptome sequencing analysis was performed at room temperature and 5 high temperature treatments.After the off-machine data was filtered,no-parameter transcriptome analysis was performed,and a total of 492,693 unigenes and 840,509 transcripts were obtained,of which 252,200 transcripts(about 30.01%of the transcripts)were annotated.Differentially expressed genes were screened with q-value<0.05 and|logFC|>1 as thresholds.Among them,the HS 12 h vs.CK 12 h group had the most differentially expressed genes,with a total of 19766 genes;in the CK 2 h vs.CK 0 h group The least differentially expressed genes were obtained,which were 3460;3337 genes showed transient functional expression in four high temperature stress periods respectively.In each comparison group under high temperature stress,GO analysis was mainly enriched in the categories of "plasmodesmata","cell wall","protein kinase activity" and "response to heat";KEGG analysis mainly enriched in"photosynthesis-antenna protein","Plant hormone signal transduction","necroptosis","MAPK signaling pathway" and other pathways.A large number of heat shock transcription factor(Hsf)genes were found in the differentially expressed genes,such as PoHsfA3,PoHsfA2b,PoHsjB2b,PoHsfB4,PoHsfCl;in addition,AP2/ERF,C2H2,bHLH,GRAS family transcription factors also showed significant differential expression after the start of high temperature stress.(3)In order to cross-validate the authenticity of the transcriptome data,11 significantly differentially expressed genes in different pathways in response to high temperature stress were selected for real-time quantitative PCR verification.The results showed that the expression trends of 11 genes were consistent with the transcriptome data.The sex ratio is more than 70%,indicating that the transcriptome data is true and reliable.(4)Carrying out weighted co-expression network analysis(WGCNA),a total of 19 modules were obtained,and the prediction results of the protein interaction network were further compared with physiological indicators.The results showed that the PSAO and LHCA3 protein-related genes of the Brown module may participate in the regulation process of the photosynthesis mechanism of peony during high temperature stress through positive and negative cross-regulation;PoWRKY53 may participate in the regulation process of peony during high temperature stress through down-regulation.PoHsfB2b of Yellow module may be a hub gene regulating the ability of peony to high temperature stress.