Transcriptome And Metabolome Analysis Of Blueberry Tissue Culture Seedlings Under NaCl Stress

Blueberry is a perennial small berry fruit tree.Belongs to Vaccinium of the family Rhododendron.Its fruit is rich in nutrition,unique flavor,rich in anthocyanins have a variety of health effects.The salinized land area in China accounts for about 10%of the salinized soil area in the world.The large salinized soil in China has severely restricted the expansion of blueberry cultivation and production area.In this study,the salt tolerance of three major southern highbush blueberry cultivars was evaluated comprehensively,and the transcriptome and metabolome of the selected salt-tolerant cultivars under different concentrations of NaCl stress were analyzed.By studying the gene expression,metabolites and main metabolic pathways of blueberry under salt stress,it is helpful to the breeding of salt-tolerant blueberry cultivars and analyze the mechanism of blueberry responding to salt stress.The main results are as follows:1.NaCl stress can inhibit the growth and proliferation of blueberry tissue culture seedlings.It can significantly reduce the fresh quality and survival rate of blueberry tissue culture seedlings,reduce the bud increment rate and slow down the growth rate of new buds.With the increase of NaCl concentration,the Na~+content and K~+/Na~+ratio of blueberry tissue culture seedlings increased gradually,and the salt tolerance of three blueberry tissue culture seedlings from strong to weak was‘Legacy’,‘O’Neal’,‘Misty’.2.Transcriptome sequencing was performed on huckleberry tissue culture seedlings under different concentrations of NaCl stress,and 59.7 Gb of original data were obtained.Compared with the control group,1166,2395 and 3346 differentially expressed genes were screened out in 30,60 and 90mmol/L NaCl treatment groups,respectively.GO functional annotation of differentially expressed genes,Biological process is mainly enriched in Cell process,Metabolic process,Stimulation response and Biological regulation;The Cell location is mainly enriched in Cells,Organelles,Membranes and membranes;The Molecular function is mainly enriched in Binding,Catalytic activity,Transport activity,Molecular function regulator and Enzyme regulation activity.KEGG pathway enrichment analysis showed that,Photosynthesis-antenna proteins,Photosynthesis,Plant hormone signal transduction and Phenylpropanoid biosynthesis are significantly enriched,and contain more differentially expressed genes.After analyzing the differentially expressed genes in the main pathways,Salt stress can inhibit the photosynthesis of blueberry and enhance the accumulation of carbohydrate.Plant hormones such as auxin,abscisic acid,brassinolipid jasmonic acid and gibberellin are also involved in the response of blueberry to salt stress.3.The metabolomics analysis of blueberry tissue culture seedlings under different NaCl stress showed that compared with the control group,489,444 and 575 different metabolites were screened in 30,60 and 90 mmol/L NaCl treatment groups,respectively.The differential metabolites were mainly enriched in Galactose metabolism,Flavone and flavonol biosynthesis,Alanine,aspartate and glutamate metabolism,ABC transporters and Biosynthesis of amino acids.Based on the analysis of different metabolites,it was found that blueberry protected the cell structure by accumulating carbohydrates,amino acids and flavonoids in the plant,and eliminated the excessive reactive oxygen species in the cells caused by salt stress,so as to alleviate the cell damage caused by salt stress.