Screening Of Genes And Its SNPs Related To Growth Of Penaeus Vannamei

Penaeus vannamei,native to the Pacific coast of South America,has strong resistance to stress,rapid growth,wide adaptability,and delicious meat,making it the most widely cultivated in the world.In this paper,four strains were preserved by Fujian Fisheries Research Institute.After mating with self-crossing and reciprocal cross-matching,16 strains of shrimp seedlings with different genetic backgrounds,plus Zhengda commercial seedlings and Fujian soil seedlings,a total of 18 strains were obtained.Germplasm improvement in shrimp was studied through aquaculture experiments,ammonia nitrogen tolerance,and transcriptome sequencing of very small individuals.The main conclusion as follows:1.Different strains of shrimp have different growth conditions,even if the shrimps of the same strain show large differences,mainly in the growth rate,disease resistance and stress resistance and food intake.The four conservation strains have poor growth traits,but their hybrid descendants 16#,15#,10#and 9#showed excellent traits,mainly in strong disease resistance,fast growth and high success rate.2.The results of ammonia nitrogen tolerance test showed that the ammonia nitrogen tolerance ability increased with the growth of shrimp,and ammonia nitrogen could affect the normal growth and development of shrimp.The excessive concentration may cause the death of shrimp.The experimental results of larvae showed that the survival rate of P.vannamei decreased with the prolongation of ammonia-nitrogen stress and stabilized after 20h.There were significant differences in the survival rates of the three groups after exposure to the three ammonia nitrogen concentrations for 48 h(p<0.05).After exposure to 40mg/L for 48h,the 15 and 17#survival rates were the highest,above 80%;16,5,8 and 7#were lower than 50%.After exposure to 60mg/L for 48h,the survival rate of 10 and 15#was the highest,higher than 70%;however 8,9,3,5,2,and 1#are less than 50%.After exposure to 80mg/L for 48h,the survival rate of 3 and 12#was the highest,and the survival rate of 13#was the lowest.The experiment showed that the four strains of 5＃,6#,7#,and 8#were less resistant to ammonia nitrogen and ranked lower in each line.5#as a maternal hybrid progeny may have high ammonia nitrogen tolerance,and the hybrid production line has strong ability to resist ammonia nitrogen.3.The size of the two samples obtained a significant difference in the total number of genes was 2292,of which 176 were up-regulated in big individuals,while up to 2116 genes were up-regulated in small individuals.This is contrary to what we expect big individuals to up-regulate genes.Moreover,the up-regulation of up-regulated genes in small individuals is very large,and the number of up-regulated expressions is more than 10 times,which is 1671;the expression of large individual genes is very small,only 7 are more than 10 times,19 are more than 4 times,and the other 150 are is between 2-4 times.Among the genes with functional annotation,the genes involved in stress and material energy metabolism were the most,with the proportions of 62.43%and 27.02%,respectively.The differential genes mainly focus on stress and energy metabolism.4.Analysis of transcriptome revealed that 235409 SNPs were detected,among which 17684 SNPS were located in the coding region of genes,leading to missense mutations and potentially affecting gene functions.However,only 170 SNPS showed significant differences,and 30 genes were screened out after eliminating duplicated genes.These 30 genes had significant SNP differences among individuals of different sizes at the same time.It was found through functional annotation that there were 9 microfilaments and microtubules,7 signal transduction,5 digestion,2 immune correlation,3 epidermal proteins and 4 unknown proteins.