Study On Gene Expression Profile And The Related Resistant Enzymes Of Hami Melon Under Cold Stress

Hami melon is a characteristic fruit of Xinjiang.It is easy to have chilling injury during the post-harvest storage process,leads to huge economic losses.The main cause of chilling injury is the low temperature in the storage.So an appropriate storage temperature is the key to solve this problem.At present,there are few studies on the mechanism of response to cold stress.The study of Golden Empress transcriptions was carried out and the cold stress of Hami melon was studied from the molecular level,which provides a theoretical basis for the response mechanism of Golden Empress to cold stress.Objective: Golden Empress,an early maturing varietiy of melon in Xinjiang were investgatied.The effects of three storage temperatures(21 ?,3 ? and 0.5 ?)on the quality and physiology of Golden Empress fruit were studied,and different samples were sequenced and the differentially expressed genes were screened.From the molecular level of research on the possible storage of Golden Empress in the process of gene types,functions and metabolic pathways through the GO function and Pathway analysis,which provides a theoretical basis for the response mechanism of Golden Empress to cold stress.Methods: The physiological indexes of Golden Empress were determined,including chilling index,weight loss rate,electrical conductivity,hardness and soluble solids;the activity of superoxide dismutase,peroxidase,catalase and chitinase was determined by kit;transcriptional sequencing of Golden Empress was carried out by transcriptome sequencing technique BGISEQ-500 sequencing platform.Results and conclusions:(1)0.5? storage of melon fruit,can effectively maintain the fruit quality;slow down the chilling index,weight loss and conductivity rise and the hardness and solubility of solid content decreased;maintain high activity of superoxide dismutase,peroxidase,catalase and chitinase to delay fruit aging and decay.(2)Through the BGISEQ-500 sequencing platform to obtain an average of 24136070 original reads and 24105793 clean reads.The average comparisons of clean reads with reference genes were 64.22%,and the average percentage of Read reads with reference genomes was 80.67%.A total of 20823 genes were identified.The number of genes identified in the samples at 0.5 ? was less,and the number of genes identified at 21? was higher.This indicates that low temperature inhibits the metabolism of melon in the storage process,thus inhibiting the expression of genes,more conducive to the preservation of fruit.(3)A total of 15741 genes were screened out from different samples of Golden Empress.The differentially expressed genes in the biological process were significantly enriched in the 23 GO-term by GO function analysis.It is mainly enriched in the metabolic process,the cellular process and the single biological process.The differential expression genes in the cell fraction were significantly enriched in 16GO-term,which mainly enriched in cells,cell parts and membranes.The differentially expressed genes were significantly enriched in 13 GO-term,which mainly enriched in catalytic activity and binding.Among them,immune regulation,response stimulus,antioxidant activity and enzyme regulation activity were related to cold stress.(4)There are 15741 differentially expressed genes in the melon fruit,enrichment in the 134-131 access road.Significantly enriched pathways include fatty acid metabolism,glutathione metabolism,metabolic pathways,secondary metabolites biosynthesis,plant hormone signal transduction,plant pathogen interactions,starch sucrose metabolism,amino acid biosynthesis,cysteine and methionine metabolism,pyruvate metabolism,valine,leucine and isoleucine degradation.