Preliminary Study On The Function Of FaMYB44 Regulating Malate Synthesis In Strawberry Fruits

There are many factors that affect the quality of the fruit.Cultivation techniques such as water and fertilizer management,sunshine duration,however,the fruit’s internal substances changes is the essence.The varieties of sugar and acid,and the ratio of sugar and acid content can affect the quality of the fruit.Organic acid is one of the important factors influencing the quality of fruits.The fruits can be divided into citric acid fruits and malic acid fruits.Strawberries are citric acid fruits.Citric acid is the highest amount organic acid in strawberries,which significantly affects the strawberries quality.Therefore,explore the molecular mechanism of accumulation of organic acids will play an important role in production.In this study,the FaMYB44 gene was cloned from the small green fruit of octoploid strawberryBenihoppe.By constructing the plant expression vector,the heterologous expression of the gene was got in Arabidopsis and NC89.The homologous transient expression directly explained that the FaMYB44 gene affects the accumulation of citric acid in strawberries.The results are as follows:1.FaMYB44 was cloned from the octopus strawberry Benihoppe.The CDS is 756 bp long and encodes 251 amino acids.According to the analysis of the Smart Protein Structure Analysis website,this sequence has two distinct SANT domains and belongs to the MYB family gene.2.By constructing 35S:FaMYB44-GFP overexpression vector and injecting Nicotiana benthamiana for subcellular localization,it was found that FaMYB44 gene was localized in the nucleus.3.Real-time PCR analysis showed that the expression level of FaMYB44 gene was expressed in the roots,stems,leaves,flowers and fruits of diploid strawberry Rugen and octaploid strawberry Benihoppe The stems of two varieties,Leaves and flowers are highly expressed,and show a downward trend as strawberry fruits mature.4.The content of organic acids in the two octoploid strawberry cultivars Benihoppe and Montery at different developmental stages was detected by high performance liquid chromatography,and it was found that malic acid showed a downward trend in the four developmental stages of the two varieties,while citric acid increased first After the downward trend.5.After treatment with hormones ABA,GA3 and ETH for 24 hours,the response pattern of FaMYB44 gene to hormones was detected,and it was found that FaMYB44 gene was down-regulated to varying degrees after the above-mentioned hormone treatments.6.The 35S:FaMYB44 overexpression vector was constructed to express heterologously in Arabidopsis and NC89,the identification showed that the FaMYB44 gene expression of heterologously expressed plants is significantly different from the control group,and the malic acid content is higher than that of the control group,and the difference is significant.The homologous transient expression in strawberry fruit by injection method preliminarily confirmed that FaMYB44 affects the accumulation of malic acid.