The Genetic Mechanism Of MicroRNARegulated Maize Aerial Root Development

Maize aerial root was closely related to lodging resistance,which determines the planting density and then yield of maize.The aerial root formation of maize was not only under the key genes determination,but also the micro RNA under a complex gene expression regulation.Micro RNAs(mi RNAs)are of a class of eukaryotes endogenous regulatory RNAs with 20-25 nucleotides in length.They can be applied to bases complementary area of target gene m RNA,realized gene expression regulation by shear target m RNA or inhibition of the target m RNA transcription translation.In this study,Chang 7-2,a maize inbred line lacking aerial root and 12246,a inbred line with flurish aerial root were selected as the experimental materials for micro RNA sequencing.High-throughput Solexa sequencing technology was processed to obtain the expression profiles of mi RNAs.The target genes of aerial root developmental micro RNAs were pridected via ps RNA Target finder.Furthermore,the expression of selected micro RNAs and their target genes were valideted by real-time quantitative RT-PCR to construct the micro RNA dependent aerial root development gene regulating network.The main results are as follows:1.High-throughput sequencing was processed to obtain 2,549,593 and 4,186,404 clean reads in Chang 7-2 and 12446,respectively.There were 202 conservative mi RNAs belonging to 27 mi RNAs families.2.32 conserved aerial root related micro RNAs belonging to 8 mi RNAs family were differently expressed in the two maize ibred lines and were the candidate micro RNAs.The expression of these candidate micro RNAs were further validated via q RT-PCR.The consistency between the two group of datashows the reliability of the sequencing results.3.Target genes of the micro RNAs were predicted by online program ps RNATarget.In total,there are 179 target genes found.12 target is detected with differentially expressed genes,there were eight target genes the corresponding expression of micro RNAs in the opposite trend,they were zma-mi R166a-i,zma-mi R396 cd,zma-mi R444 ab,zma-mi R528 ab,zma-mi R827,Indicated these mi RNAs regulated its target genes that involved in the aerial root growth of maize inbred lines;GO(Gene Ontology)annotation were processed to these predicted target genes,to find that most of them are transcription regulatory factors.Others are genes involved in metabolic pathway,including hormone signal transduction,metabolism,stress response,electron transport etc.Based on the expression data of micro RNAs and their target genes,a micro RNA-dependent regulatory network was constructed in the developing aerial root of maize.