Identification And Analysis Of Micro-exon In Indica Rice Minghui 63 And Zhenshan 97

Micro-exons are those exons shorter than 51 bp.Moreover,the short length and the lack of statistical property of micro-exons always make them computationally difficult to be identified in genome annotation and transcriptome analysis.In recent years,micro-exons in human were reported to be related with some diseases in human,while there are only a few reports about micro-exons in plant.We used RNA-seq data of panicle,flag leaf and shoot to predict micro-exons in indica rice Minghui 63 and Zhenshan 97 and found that there are 3410 and 3236 newly predicted micro-exons presented in Minghui 63 and Zhenshan 97,among these micro-exons,267 and 237 are newly predicted.We made preliminary analysis and summary for the splicing features and molecular function of micro-exons.The length of 87%micro-exons tend to distribute in the range of 30bp to 51bp and the length of flanking intron of CS micro-exons tend to be short.The splicing sites of AS micro-exons are more canonical than other types of exons.Our study preliminary explored the function of micro-exons.92%of the micro-exons are located in open reading frame,but only about 25%of them are multiple of 3.Micro-exons with non-multiple of 3 are likely to cause a shift of the mutation,which indicates that the splicing of the micro-exons is not conductive to the expression of the transcript.By analyzing the GO function of transcripts,we found that micro-exons are presented in a number of biological processes,biological responses and cell components.This represents that the presence of micro-exon is very extensive.The micro-exons of Minghui 63 and Zhenshan 97 are enriched in the domain regions of DAHP synthase,phospholipid related enzyme and NAD(P)synthase.Though micro-exons are very short,they may play very important roles in many biological processes.By calculating the percentage splicing index coefficient,we found that micro-exon has tissue specificity.There are 238 and 199 tissue specific micro-exons in the shoot of Minghui 63 and Zhenshan 97.We found that the splicing of micro-exons are tissue specific by the comparison of Pearson Correlation Coefficient.We found that the splicing of some micro-exons are related with temperature and sunlight by T-test.By studying the micro-exons of 7 related species of rice,we found that they have high sequence conservation.