Mirnas And Their Expression During The Seed Development In Wheat

Wheat is an important food crop, the seed development process is the critical period for determining the yield and quality and it is significant to investigate the molecular regulation mechanism of the wheat seed development. miRNAs were an important small non-coding RNA, which play an important function in post-transcrptional regulation of gene expression. In order to explore the role of miRNA in wheat during the seed development, the miRNA of the Yumail8seeds at different stages which including5,10,15,25days after pollination (DAP), respectively, were system analyzed by using the Solexa high-throughput sequencing, and the candidate of miRNA were verify by the real-time quantitative PCR. The main results were as follows:1. The15,244,604,15,495,701,16,470,077and16,053,184raw sequences were obtained in the four samples by high-throughput sequencing, then13,525,513,14,460,398,15,310,251and13,282,907high-quality sequence were acquired respectively. After removing the repeat sequence,3,492,987,6,015,357,9,243,757and6,200,456unique reads were obtained in the four tested materials. The sequence were mainly18nt-25nt in length, which accounted for97.32%,97.97%,98.33%,94.82%, respectively, in the total number of sequencing. The largest proportion is24nt in length.2.63known miRNA were identified in the wheat seed, in which14were up-regulated and3miRNAs were down-regulated (miR825, miR1852, miR2101) during the seed development, the others were vibrate.12known miRNA were the same as that of different tissues of the wheat,31miRNA were specific found, but4involved in other tissues, were disappeared in the wheat seed; The further analysis showed that26conserved miRNAs were also detected in rice seed.3.54novel miRNA are predicted by Mireap, which included34miRNA*sequences. The expression levels of9novel miRNAs were very higher in four tested tissues.9novel miRNA were up-regulated and two (ta-MI104,ta-MI158) of them were down-regulated during the seed development.17miRNAs were only detected in one stage and12were expressed in all the four samples.4.326target genes are predicted for53of54novel miRNAs, in which ta-MI104did not find the corresponding target genes. The prediction results showed that the seven of miRNA target genes involved in protein ubiquitin degradation pathway, as well as eight protein kinase may be involved in cellular signal transduction. Others are involved in a variety of physiological pathways during wheat seed development process.5. The expression of six miRN As verified by RT-PCR, the expression trends of four miRNAs (miR167, miR397, ta-MI149, ta-MI142) were consistent with the high-throughput sequencing result, while two (miR1852and ta-MI102) were slightly different, which indicated that the high-throughput sequencing was an effective method for finding miRNA.