The Comparative Study Of Total Carotenoid Content In Different Tissues Of Paphia Undulata And Transcriptome Analysis With Foot Color Differences

Paphia undulate was one of the most important marine economic shellfish in the coastline of southeast China.The annual production of P.undulate about 100,000 tons.The study on the total carotenoid content(TCC)in different tissues and the molecular mechanism of foot color with different in P.undulate were of great significance for the selection and breeding of excellent varieties of P.undulate.In this study,we firstly assay TCC in different tissues of P.undulata and found the foot with the highest levels of TCC.Then we analysis of the relationship between color index and TCC in foot,and last the foot transcriptome of P.undulate with different color were studied.The main results were as follows:1.Selected 30 male and 30 female individuals randomly.The TCC in five tissues of P.undulata including foot,mantle,gill,adductor muscle,and gonad were analyzed by ultraviolet spectrophotometry.The results showed that there were significant differences among five tissues(P<0.01)except the mantle and gill(P>0.05).The TCC of each tissue from high to low as follows: foot,gonad,mantle,gill,and adductor muscle.There was no significant difference in foot,mantle,gill,adductor muscle between male and female(P>0.05),but the TCC in testis was higher than in ovary(P<0.05).This study preliminary reveal the regularities of distribution of TCC in P.undulata.2.The TCC and three color indexes L *(brightness),a *(values of red,green),b *(values of yellow,blue)of 91 P.undulate foot samples were examined by ultraviolet spectrophotometry and colorimeter respectively.Statistical analysis showed that TCC and color index L *,a *,b * have highly significant correlation(P<0.01),the correlation coefficients were-0.733,0.685,0.775 respectively.3.From the transcriptome sequencing,assembling,annotation analysis of the orange and the light white foots of P.undulata,a total of 48.22 Gb Clean Data were obtained from 6 samples.The Clean Data of each sample reached 6.75 Gb,and more than 87.96% sequencing data of had a quality score of Q30.A total of 58,159 Unigene were obtained after assembling,the N50 is 1461,and the average length is 889.51 bp.Among them,Unigene with a length of 1 kb or longer had 16647.19070 unignes were annotated using BLAST searches against the Pfam,NR,SwissProt,COG,GO,KEGG and KOG databases.A total of 6946 SSR markers were obtained by SSR analysis.A total of 107 transcripts were identified as different expressed genes(DEGs).In the orange-colored foot group,74 genes were up-regulated relative to the light white group,and 33 genes were down-regulated.12 color-related differentially expressed genes were selected for verification by quantitative real-time PCR.The obtained different gene expression trend was basically consistent with the transcriptome sequencing results.The present results preliminarily expounded the molecular mechanism that caused the color difference of the p.undulate foot,providing important basic information for the research of subsequent functional genes and molecular breeding.