Analysis Of Related-microRNA At Two Period Of Maize Endosperm Development

Maize endosperm is the main organ of nutrients accumulation and storage, and accounts for more than 80 percent of grain weight. Maize endosperm's development is a very complex physiological and biochemical process involved in temporal and spatial expression of many genes and multiple metabolic pathways.Although many studies on kernel endosperm forming mechanism have been conducted and have made good progress. little is known about the development mechanism of grain endosperm especially in the molecular level.Gene differential expressions are the molecular basis of plant development, differentiation, aging and other biological phenomena, the analysis of genes expressed features at different stages can provide vital information for gene function and the molecular mechanisms of endosperm development. miRNA is located in the regulation center of gene expression, is an indispensable means of gene regulation,which plays an important role in maize growth and development. The next-generation sequencing technology (Solexa) afforded an effective approach for indentification of miRNAs, which has become the first choice of miRNA research.Based on Solexa we can explore a wide range of known and unknown, conservative and non conservative miRNA from the whole genome, we can also explore the miRNA expression differences between the samples.In order to further clarify the molecular mechanism of grain endosperm development, this study analyze the expression differences of miRNA between two crucial period of endosperm development in inbred lines 08-641 by solexa sequencing.The findings of the research are as follows:(1):Through Solexa technology we obtained 34,154,000 high-quality reads in the critical period of endosperm development. All miRNA mainly distributed among 21-24nt in length, and 24nt is the main type and accounts for about 51.62%.(2):Compared with the maize genome database and Rfam, we found 31,913,304 miRNAs in two samples after exclusion completely matched sequence.Further contrasted with miRBase, we got 124 conserved miRNAs and 275 novel miRNAs.The,89 known miRNA belonged to 27 conserved miRNA families.The MFE is above-20. About 89% of the mature miRNAs begin with U, and distribute on almost each chromosome.(3):The results of target gene prediction showed that only 46 putative target genes have functional annotations, and most of them were involved in various processes of plant growth and development, such as transcription regulation, stress response, plant hormone regulation, substance and energy metabolism, signal transduction, etc.(4):In addition to the above functions,91 novel miRNAs are also targeted on so many enzymes and transcription factors, such as phosphofructokinase, glyceraldehyde phosphate dehydrogenase, F-box protein, TCP-domain protein, SBP-domain protein, SPL transcription factor, zinc/iron transporter protein, cell cycle protein, fiber synthase, ribonucleoprotein, etc. which are all associated with sugar, fat and protein synthesis.