Isozyme expression tissue difference and genetic diversity of Macrobrachium rosenbergii

【Objective】The isozyme locus and zymogram phenotypes of Macrobrachium rosenbergii population were analyzed from the perspective of biochemical genetics, so as to clarify the genetic diversity of different populations, and provide basic data for the identification of germplasm resources and genetic breeding research.【Method】In this experiment, malic acid dehydrogenase(MDH), superoxide dismutase(SOD), sorbitol dehydrogenase(SDH), malic enzyme (ME), phosphopanase(PGM), alcohol dehydrogenase(ADH), glucose-6-phosphate dehydrogenase(G6PDH), lactate dehydrogenase(LDH), glutamate dehydrogenase(GDH), aspartate dehydrogenase(AAT) and esterase(EST) in muscles, eyes, gills, heart and hepatopancreas of M. rosenbergii were studied by polyacrylamide gel electrophoresis(PAGE). And muscle isozymes were selected to study the genetics of five populations of M. rosenbergii, including Shencao population, wild population, disease resistant population, growth population and Zhejiang population(introduced species of shrimp in 2017).【Result】There were obvious differences in the total number of zymograms and the color of enzyme bands (enzyme activity) of the same isozymes in different tissues of M. rosenbergii, that was, the isozymes of M. rosenbergii had obvious tissue difference. There were 26 loci of 11 isozymes in 5 tissues of M. rosenbergii. Among them, EST was not expressed in muscle, but more in hepatopancreas;ME was expressed in muscle, compound eye, gill, heart and hepatopancreas;SOD-2 was only expressed in hepatopancreas;PGM was expressed more in hepatopancreas and heart. There were 11 loci in the 7 isozymes in the muscle of M. rosenbergii. Three loci(SDH-1, PGM-3 and IDH-1) were polymorphic, and the proportion of polymorphic loci was 27.27%. The average expected heterozygosity of the five M. rosenbergii populations was 0.1006-0.1416, the average observed heterozygosity was 0.1143-0.1762, and the Hardy-Weinberg genetic deviation index(0.1362-0.2444) was positive, that was, it deviated from the Hardy-Weinberg equilibrium.【Conclusion】The isozymes of M. rosenbergii have obvious tissue difference, which shows that there are obvious differences in the total number of zymograms and the color(enzyme activity) of enzyme bands between different tissues. Therefore, the isozymes can be used as a biochemical genetic marker to study the genetic diversity of M. rosenbergii. The five populations are all in the state of heterozygote excess, and their genetic variation levels are high.