A Pilot Study Of Crayfish (Procambarus Clarkii) MicroRNA Profile Under Salt Stress

ABSTRACT:In recent years, crayfish farming in saline and alkaline land has emerged in China. However, the salinity of saline land is one of the most crucial abiotic stress for crayfish farming. The weakness of basic theoretic study often leads to mismanagement, causing extensive death of crayfish consequently. Even some crayfish manage to survive, the growth is slow and the yield is relatively low and quite unstable.Investigating the stress-response mechanism of crayfish when exposed to saline water, improving the salt tolerance of crayfish using genetic engineering method and cultivate the new variety breeding is the main method to make the salinization land useful and improve the yield of crayfish.Methods In this experiment we examined the samples of freshwater crayfish (type A) and saline water crayfish (type B) employing Solexa high throughput sequencing technology to build a small RNA library to get a differentiated miRNA profile for crayfish. Several miRNA that expression has changed were selected after analyzing the Solexa results. We then validated the expression level of these miRNAs in type A and type B crayfish Taqman Probe-based qRT-PCR.Results (1) we acquired 469,044 small RNAs which has the length ranging from 18-30nt, by comparing with decapod genome, we selected 78 kinds of conservative miRNA.8 of which were expressed in type A crayfish specificly,18 of which were expressed in type B crayfish specially.In conclusion, about 10 miRNAs were related to the stress-response mechanism of crayfish (2)We used qRT-PCR examined the expression level of the 10 miRNAs, we discovered the down-regulation of expression of miR-2a-3p、miR-1-3p、miR-279、miR-184-3p、miR-71、miR-let-7-5p、 miR-276-3p and the up-regulation of miR-275-3p when crayfish were under salt stress. Besides, the expression level of miR-71、miR-276-3p、miR-let-7-5p、miR-184 decreased significantly, the expression level of miR-275increased significantly. The expression level of miR-276、miR-71、miR-let-7-5p decreased as salinity increased, and the change were significant statistically.