Transformation Of Rice With Br-related Genes And Analysis Of Salt Tolerance Of Transgenic Plants

Brassinosteroid (BR) is a class of steroidal hormones, playing important roles inplant growth and development. BR can promote plant growth and enhance plantresistance to environmental stresses. The picture of BR signalling is emerging in recentyears. The main components of BR signal transduction includes two receptor kinase BRIland BAK1, a GSK3-like kinase BIN2, two homologous transcription factors BZRl andBES1. BZRl and BES1are two important transcription factors in the nucleus, playingessential roles in regulating BR biosynthesis and downstream growth responses.Considering that BR can enhance plant resistance to environmental stresses, in thisstudy, we used BR signal transduction related genes BZRl, BES1, mBZRl, mBES1andmOsBZRl (OsBZRl, the BZR1homologou gene in rice; m-mutantion) to transform rice,hoping to facilitate further studies on the function of BZR1and BES1in regulating BRsignalling and the expression of BR-induced genes, and therefore developing strategy forcrop improvement by regulation of BZRl and BES1. The main results are as follows:1. The plant overexpression vectors pUN-mBES1, pUN-BES1, pUN-mBZR1,pUN-BZR1and pUN-mOsBZR1were constructed and introduced to Agrobacteriumtumefaciens strain EHA105.2. The five plant overexpression vectors pUN-mBES1, pUN-BES1, pUN-mBZR1,pUN-BZR1and pUN-mOsBZR1were transfered into rice cultivar Nippobare mediated byAgrobacterium, and twenty-five, thirty-three, three, nine and twenty-eight positive transgenicplants were obtained, respectively.3. The expression of target genes in the transgenic plants was analyzed usingsemi-RT-PCR. The rerults indicated that all the five genes were overexpressed.4. By treating T1transgenic plants with salt stress, one mBES1transgenic plants andthree mOsBZR1transgenic plants showing increased salt tolerance were obtained.