Identification And Analysis Of MicroRNA Associated With Sweet Corn Seed Vigor

micro RNAs(mi RNAs), a newly discovered class of non-coding small RNAs, have been reported to involve a broad range of metabolic and physiological processes in plants, such as plant growth, development and stress response. They participate in gene expression by degrading target gene at post-transcriptional levels.Seed is the basic element of plant growth and is important material for agriculture.Studying the mi RNA in seed will contribute to improve seed vigor and storage ability.With seeds of the sweet corn Yuetian 13 as material, we managed to explore the correlation between mi RNA and seed vigor in this paper. Firstly, seeds with different vigor level were obtained by artificial aging treatment. Secondly, the expression of mi RNAs in embryos ware compared among these seeds by deep sequencing and the differently expressed mi RNAs were further verified by real-time quantitative PCR technology(RT-q PCR). Moreover, by degradome sequencing, the target genes and their relative functions were identified of these mi RNAs. The main results are as follows:1. With sustained artificial aging under 45℃, 100% RH condition, seed vigor decreased gradually. The germination percentage of Yuetian 13 reduced to about 50%after 2d of aging.2. The expression of mi RNAs were analyzed by deep sequencing between two different vigor levels of sweet corn embryos. There were 27 mi RNAs expressed differently, in which 17 mi RNAs were up-regulated and 10 mi RNAs were down-regulated(p<0.5).3. Among 10 selected differentially expressed mi RNAs, 5 mi RNAs were up-regulated while 5 mi RNAs were down-regulated, using real-time quantitative PCR analysis, which was consistent with deep sequencing results.4. We found that the target genes included membrane-anchored ubiquitin-fold protein and peroxidase superfamily protein by degradome sequencing. Seed aging will destroy the integrity of membrane. According to the changes of membrane and lipid oxidation, so it could be speculated about the fact that the expression ofmi RNAs may participate in the regulation of seed vigor.