Studies On The MiRNA Regulation Mechanism Of Heteromorphic Leaf Development In Populus Euphratica

Populus euphratica is an important woody plant in arid and semi-arid desert areas in northwest China.In a long time process of coping with extreme natural environments,P.euphratica has formed a variety of leaf morphology,which is the external manifestation of different growth stages.Plants generally go through different stages during the growth process.In the transition of growth stage,the changes of different phenotypic characteristics occur synergistically in space and time and interact with each other,ensuring the growth of plants themselves and the reproduction of the next generation.MicroRNA?miRNA?is a class of endogenous non-coding RNA with a length of about 22nt.MicroRNA is generally highly conserved in sequence,express spatial and temporal,and is widely involved in the regulation of post-transcriptional expression of genes.In recent years,research has shown that miR156 and miR172,and SBP/SPL transcription factor family,involved in the development phase changes in a variety of plants,and differentially expressed in juvenile and adult tissues in herbs and woody plants,which shed a light on the research of molecular mechanisms duiring phase changes.P.euphratica leaf materials used in this research were from Inner Mongolia and Xinjiang region.Dig and characterise differentially expressed miRNAs?DEmiRNAs?through high-throughput sequencing,predict target genes of DEmiRNA,and compare the expression patterns of miRNA from the two location.The research results obtained in this study are as follows:1.87 conserved miRNAs?known miRNAs?were identified and 80 novel miRNAs?novel miRNAs?were predicted in the sRNA database of Inner Mongolia by high-throughput sequencing technology.129 conserved miRNAs?known miRNAs?were identified and 62 novel miRNAs?novel miRNAs?were predicted in the sRNA database of Xinjiang.Differential expression analysis identified 52 differentially expressed miRNAs?DEmiRNAs?in linear and broad-ovate leaves of P.euphratica in Inner Mongolia,including 29 known miRNAs and 23 novel miRNAs.25 DEmiRNAs,including 17 known miRNAs and 8 novel miRNAs,were identified in the heteromorphic leaves of P.euphratica from Xinjiang.Mir156a-5p,mir157a-5p,miR164a,miR399a and miR827 were differentially expressed in both leaves of Inner Mongolia and Xinjiang.A total of 511 target genes were identified by degradation sequencing2.Comparing miRNA expression patterns in heteromorphic leaves on the whole tree and single branch dimension of P.euphratica from Xinjiang.It was found that except miR164,miR167,miR166 and miR396,most miRNA were poorly in research foundation,such as miR6457,miR8607,miR7767,miR5230,miR5139,miR7831,miR8155,novel₁,novel 41,novel₃1,novel₅4.3.Comparing miRNA s found in Inner Mongolia and Xinjiang,it was found that miRNA s in the two places were significantly different,and only 45 miRNA s?39 known miRNA s and 6 novel miRNA s?were repeated in two sequencing librarys.It mainly includes miR1447,mir156/157,miR159,miR160,miR162,miR164,miR166,miR167,miR168,miR170,miR171,miR172,miR2111,miR2912,miR319,miR3627,miR390,miR393,miR394,miR394,miR399,miR403,miR472,miR473,miR47 7,miR482,miR6445,miR6457,miR827,miR858 families.Most of these recurrent miRNAs are functionally important and essential for normal plant growth.4.Through comparative analysis of miRNA expression patterns in different areas?Inner Mongolia and Xinjiang?,and the whole tree and single branch dimensions,a batch of DE miRNAs were selected.Analysis of these miRNA target genes functions were mainly involved in the response path of plant hormones5.We transformated peu-MIR172a to Arabidopsis thaliana by folar dip method.Expression levels of miR172a and MIR172a were higher than that in wild-type.The transgenic Arabidopsis have a much shorter juvenile stage,and an earlier flowering time than wide-type.We choose heteromorphic leaves of P.euphratica as the material in this research to study mechanism of miRNAs participate in phase change.Inner Mongolia and Xinjiang are two geographically far apart sites with notably different environment.The results of the analysis not only reveals how the miRNA participate in the phase change but also reflects different expression patterns of the miRNA under different environment.The result we get will provide an important reference and basis for the development phase transformation process of woody plants of molecular regulation mechanism.