| Plum is one of the characteristic fruits in Inner Mongolia Autonomous Region,with large planting area and considerable output value.There is an urgent demand for post harvest storage.Short shelf life at normal temperature and poor adaptability to low temperature are the main difficulties of plum fruit postharvest storage.The phenomenon of chilling injury greatly restricts the application of cold storage technology in plum fruit postharvest storage,and is the bottleneck of plum fruit storage.In this experiment,the effect of cyanogen resistant respiratory activator on the chilling resistance of plum fruit was studied.Then Ps AOX gene was over-expressed in the flesh of plum fruit at the early ripening stage by transient transformation technology,and transcriptomic analysis was carried out to preliminarily analyze the mechanism of cyanogen resistant respiration improving the cold storage quality of postharvest plum fruit.The main results are as follows:(1)The effects of cyanide resistant respiration on the chilling resistance of plum fruits were studied by soaking plum fruits with 1 m M,5 m M,10 m M,50 m M pyruvic acid and 5 m M salicylhydroxamic acid(SHAM)as cyanide resistant respiratory activators for30 min and soaking plum fruits in distilled water for 30 min.The results showed that the inhibition of cyanide resistant respiration by SHAM inhibitor treatment could promote the occurrence of plum fruit chilling injury and aggravate the symptoms of fruit chilling injury;The treatment of pyruvic acid,a cyanide resistant respiratory activator,could inhibit the occurrence of chilling injury of plum fruits during low temperature storage,and this inhibition had a concentration effect.Among them,5 m M pyruvic acid treatment can effectively inhibit the chilling injury of plum fruit,reduce the occurrence rate and chilling injury index of fruit,slow down the damage of cell membrane of plum fruit,maintain the integrity of cell membrane,slow down the rise of polyphenol oxidase(PPO)and peroxidase(POD)activities,slow down the production and accumulation of hydrogen peroxide in fruit,and improve the active oxygen scavenging capacity and chilling resistance of fruit,Promoting the synthesis of endogenous ethylene and increasing the activity of alternative oxidase(AOX)can effectively maintain the quality of plum fruits during low temperature storage.10 m M and 50 m M pyruvate treatment could significantly activate the expression of Ps AOX and Ps CBF genes in fruits.After transient transformation,the over-expression pulp tissue with Ps AOX gene expression increased by 3.5 times was obtained.The transcriptome sequencing showed that a total of 50.99 GB data was obtained,the clean data of each sample reached 7.59 GB or more,and the percentage of Q 30 base was 91.92 % or more.Gene differential expression analysis showed that 2033 genes were changed in Ps AOX over-expressed fruits,of which1340 genes were up-regulated and 693 genes were down regulated.A total of 2020 differential genes were annotated into the seven databases by transcriptome annotation.Go enrichment analysis of differential genes showed that Ps AOX over-expression fruit differential genes were mainly enriched in cell,binding function,cell process and other branches.The largest number of differential genes annotated by COG is the main function prediction,and 228 differential genes are annotated.KEGG annotation results show that the number of genes annotated to the metabolic pathway is the largest in the primary metabolic pathway,which is 318 differential genes.In the secondary metabolic pathway,the number of genes annotated to the carbohydrates metabolic pathway is the largest,which is 116 differential genes.The enrichment results of KEGG pathway showed that the differential genes were mainly enriched in fatty acid degradation pathway(8 differential genes)and phenylpropane biosynthesis pathway(33 differential genes). |
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