Effects Of Blue Light Irradiation On The Expression Of MicroRNA In Saccharina Iaponica

Light plays significant roles in algal growth and development, and blue light iscritical to the growth and development of Saccharina japonica. In this study, base onthe high-throughput sequencing, bioinformatics analysis and real time quantitive PCR(qRT-PCR), we analyzed the effect of blue light illumination on the microRNAsprofile of S. japonica and obtained microRNAs (miRNA) in response to blue light.We conducted small RNA libraries construction and sequencing to the juvenilesporophyte of S. japonica which treated with blue light and darkness respectively.Totally,20novel miRNAs were predicted by Mireap software after categorization ofthe small RNA. Comparing to the genome information of Ectocarpus siliculosus, wededuced the secondary structures of all novel miRNAs. Of which, sj-MIR07,sj-MIR16and sj-MIR20exhibited over one type of the secondary structure. Most ofthe objective candidate genes of these novel miRNAs are conserved and the deducedfunctions are varied from catalyzation to responses to stresses. Transcriptions of thesj-MIR05, sj-MIR07, sj-MIR12and sj-MIR15were upregulated under the blue lightcondition. Differential expression analysis showed that739known miRNAs and6novel miRNAs differentially expressed and related to blue light responses. However,only some results of the qRT-PCR detection were partially consistent with that fromthe sequencing data, this may attributed to the library construction methods applied.With the integration of the GO enrichment analysis, KEGG pathway analysis anddifferential expression data, we deduced the potential miRNAs (i.e. miR398, miR1110,miR2840) might be involved with blue light physiological pathway, and wereregarded to be involved with receptor signaling, response to radiation, plant circadianrhythm, photomorphogenesis, response to light stimulus, photoperiodism andphototransduction. Further studies are needed to be conducted for the verification ofthe function.