The Primary Study Of MiR167 Function In Glycine Max And Lotus Japonicus Using Short Tandem Target Mimic

Soybean(Glycine max)is one of the most important economic sources of vegetable oil and protein worldwide.It is widely planted in the world,especially in China’s agricultural production plays a very important role.However,due to the special geographical environment in China,the yield and oil content of soybean are not high,and the soybean industry in China is easily affected by high temperature,drought and salt stress,and the soybean industry is facing great challenges.Therefore,it is of great significance for the development of soybean industry in China to explore the molecular mechanism of soybean stress response and cultivate new soybean varieties with high yield and stress tolerance.MiRNAs are a class of endogenous non-coding RNAs of 20-24 nt in length,which negatively regulate gene expression mainly by mediating target gene silencing at posttranscriptional level.The plant mi RNAs are essential regulators of many biological processes.Many conserved and novel mi RNAs have been identified in soybean,but the detailed functional characterization of mi RNAs is still lacking.Utilizing the mi RNA knockdown technology,Short Tandem Target Mimic(STTM)approach,we generated a series of mi RNA knockdown lines in soybean.On the basis of proving that the short tandem target simulation technique is efficient and feasible in stable genetic transformation of soybean,the function of mi R167 in soybean was analyzed.We found that Gmmi R167 participated in the response to drought stress.The expression of Gmmi R167 was repressed under drought conditions of wild-type plants.When Gm STTM167 transgenic plants were subjected to drought stress,the chlorophyll content and relative water content in leaves were significantly higher in Gm STTM167 transgenic plants compared with that of wild type,and the drought tolerance of Gm STTM167 transgenic plants was stronger.These results indicates that Gmmi R167 negatively regulates the response of soybean to drought stress.The model legume Lotus japonicus is important as agriculture forage sources,which is widely planted in the world.It harbors valuable natural products,and plays an important role in symbiotic nitrogen fixation and moisturizing water and soil.Different from the tetraploid genome of soybean,the genome of Lotus japonicus is diploid.To uncover whether the function of mi R167 is conserved in legume,we also generated the stable mi R167 knockdown transgenic lines using STTM approach,and this laid a foundation for further study of mi R167 function in Lotus japonicus,and comparison of the function of mi R167 between soybean and Lotus japonicus.In summary,we utilized the STTM approach to generate mi RNA knock down lines to study mi RNA function in soybean.On the one hand,we proved that STTM technology was powerful and effective in soybean stable transformation.On the other hand,mi R167 knockdown lines,Gm STTM167,was generated,and its function was analyzed.We found that mi R167 plays an important role in regulating drought response of soybean.Meanwhile,in order to explore whether the function of mi R167 is conserved in legume,the stable mi R167 knockdown transgenic lines of Lotus japonicus,Lj STTM167,was also obtained.These works laid a good foundation for the further study of the function of mi R167 in soybean and Lotus japonicus.