Cloning And Function Analysis Of MYB17 In Marchantia Polymorphia L.

Marchantia polymorpha L.,is a bryophyte model plant.Its reproductive strategy in field involve sexual(spores)and vegetative(thallus and gemma)pathway.M.polymorpha possesses many advantages for various researching works,such as cultivation easily,short life history,highe reproduction index for gemmae production,and so on.To this day,the molecular mechanism involved in gemma development is not yet clear.To explore the molecular basis of gemma development,in this thesis,transcriptome sequencing for materials during various gemmae developmental stages,DEG(differential expressed genes)screening,transformants over-expressed and edited through CRISPR-Cas9 system for candidate gene,and observation for transformants’ phenotype were carried out.The main study results are presented as follows:1.Transcriptome sequencing of materials form three periods of gemmae development(primordium formation,early/middle stage of gemma development,gemma maturity)and analysis of DEGs showed that MpR2R3-MYB 17 gene may be involved in the regulation of gemmae development in M.polymorpha.2.Bioinformatics analysis show that MpR2R3-MYB 17 codes a hydrophilic,non-transmembrane protein without signal peptide.The promoter analysis showed that MpR2R3-MYB 17 not only involved in auxin response,but also involved in the light,meristem reaction.3.The over-expression vector PBI121-MpR2R3MYB17 and the editing vector PEGCas9P35s-MpR2R3 MYB 17 were successfully constructed.4.Genetic transformation of M.polymorpha were carried out through non-tissue culture dependent genetic transformation method.36 of the overexpression-positive plants initially identified by PCR had phenotypic changes relative to control plants,and nine of the 24 positive-edited plants achieved successful editing.5.Over-expression transgenic plants have two kingds of phenotypes: 1)increasing significantly of gemma-cup density on thallus and increasing non-significantly of gemma in cup;2)tissues similar to callus development on thallus.Expressions of MpR2R3-MYB 17 are correlated to these differential phenotype determined by qRT-PCR analysis for these transgenic plants.For edited individuals,gemma cups on thallus and gemma in cup decreased significantly.In conclusion,results of this thesis indicated that MpR2R3-MYB17 involved in regulation of gemma development in M.polymorpha.Further researching works about molecular mechanism of gemma development should be carried out based on this data.