Identification of F6'H Family Genes in Stem Lettuce and Preliminary Study on Its Correlation with Browning of Fresh-Cut Lettuce
In order to further explore the role and mechanism of feruloyl-CoA 6'-hydroxylase(F6'H)in browning process of fresh-cut lettuce,the F6'H-family genes were identified from the stem lettuce genome by Blastp and domain screening,and then the bioinformatics characteristics and expression during browning of these genes were analyzed,and the changes of browning degree and total phenols content of fresh-cut lettuce during storage were determined.The results showed that a total of 11 stem lettuce F6'H genes(LsF6'Hs)were identified.All the LsF6'Hs were hydrophilic proteins localized in cytoplasm with amino acid number ranging from 181 to 840,molecular weight ranging from 20.74 to 93.35 kDa,isoelectric point ranging from 5.16 to 8.36,fat coefficient ranging from 82.28 to 102.98,and instability index ranging from 26.13 to 55.39.During the storage process of fresh-cut lettuce,the expression of LsF6'H9 gene obviously upregulated,the expression of LsF6'H3 and LsF6'H11 also upregulated at 4~6 days after storage,and the other genes changed a little in expression level.The browning degree of fresh-cut lettuce increased gradually during storage,and the total phenols content increased first and then decreased,which reached the highest level on the 6th day.The corre-lation analysis showed that there was a significant positive correlation between total phenols content and brown-ing degree,indicating that the accumulation of phenols might be an important factor leading to browning of fresh-cut lettuce.The browning degree and total phenols content were positively correlated with the expression level of LsF6'H1、LsF6'H2、LsF6'H3、LsF6'H4、LsF6'H9、LsF6'H10 and LsF6'H11 during storage of fresh-cut lettuce,especially their correlations with LsF6'H9 expression,which reached very significant and significant levels,respectively.It suggested that LsF6'H9 might play an important role in browning of fresh-cut lettuce.These study results could provide the theoretical basis for further exploring the role and mechanism of F6'H in browning process of fresh-cut lettuce.