Functional Study Of The MADS-box Gene SlMBP10 In Tomato

MADS-box gene family is an important transcription factor family widely existed in aminal,plant,and fungi.It has a conserved MADS-box domain.MADS-box genes in plants are involved in series of growth and development processes,such as the formation of flower,fruit ripening.As one of the vegetable crops widely grown in the world,tomato requires a relatively stable environment for plant growth and development.However,abiotic stress involving drought,high salt has seriously affected the yield and quality of tomato.At present,the research of MADS-box on tomato was focused on their effect on the formation of flower and development of fruit.However,there are few studies focused on the effect of MADS-box genes on the abiotic stress of tomato.Therefore,it is important to investigate the role of MADS-box genes in response to abiotic stress in tomato.In the study,a MADS-box gene,SlMBP10,was cloned and characterized in bioinformatics.To investigate the function of SlMBP10,the SlMBP10 RNA interfere transgenic tomato plants were generated by Agrobacterium-mediated transformation.The main results are as follow:（1）Bioinformatic analysis of SlMBP10.The cDNA of SlMBP10 was accessed from Solanaceae Genomics Network.Sequences alignment and phylogenetic analysis showed that SlMBP10 belongs to MIKC^C type MADS-box transcription factor family.The promoter of SlMBP10 was shown to have some transcription factor binding elements that relate to stress.（2）The expression pattern analysis of SlMBP10.It is showed that SlMBP10 is highly expressed in vegetative tissue including root,stem,and leaf.A further investigation showed that the expression of SlMBP10 could be affected by hormones such as ABA,while it has a higher expression when plants treated with salt or drought stress.These data indicate that SlMBP10 may be related to growth development and plant response to salt and drought stress.（3）Generation of SlMBP10-RNAi transgenic plants.The construct which carrying SlMBP10-RNAi T-DNA sequence was built and transformed to tomato through Agrobacterium-mediated method.The positive tissue culture plants were selected by a PCR using primers specifically bind to marker gene NPTII.The transgenic SlMBP10-RNAi plants had no change in pollen and fruit development compared with wild type.However,they had abnormal growth of stem.Together with the responseness of SlMBP10 to abiotic stress,it is hypothesized that SlMBP10 may be involved in abiotic stress response and it should not make effect on the vegetative and reproductive process in tomato.（4）The responseness investigation of SlMBP10-RNAi T1 seedling to salt and drought stress.The SlMBP10-RNAi seedlings were showed to have earlier wilty than wild type when treated with high concentration salt.Consistently,the chlorophyll content and relative water content of salt treated SlMBP10-RNAi leaves were all reduced compared with wild type,while MDA content was significantly increased in these transgenic plants.Specific genes related to stress response and chlorophyll accumulation were affected by salt treatment in SlMBP10-RNAi leaves.A similar characterization was showed for seedlings with drought treatment.With incubation of leaves in salt solution,SlMBP10-RNAi leaves had significantly reduced chlorophyll content than wild type.Moreover,The growth of seedlings was significantly repressed in SlMBP10-RNAi lines when SlMBP10-RNAi and wild type seedlings were incumbated on MS medium with salt.These results suggeste that downregulation of SlMBP10 could reduce plants resistance to salt and drought stress in tomato.（5）Sensitivity analysis of SlMBP10-RNAi seedlings to three hormones.The sensitivity assay of SlMBP10-RNAi seedlings to ABA,IAA,and GA₃ revealed that,with ABA treatment,SlMBP10-RNAi seedlings had shorter hypocotyl and root compared with wild type.However,there is no difference between SlMBP10-RNAi seedlings and wild type when they were treated with IAA or GA₃.These data indicate that downregulation of SlMBP10 enhanced plant sensitivity to ABA but had no obvious effect on plant response to IAA and GA₃.In summary,the SlMBP10 gene was isolated from tomato and its role in abiotic stress response was characterized.It provides a theoretical basis for further research on the function of SlMBP10 and the molecular mechanism of the abiotic stress response.