Based On The Function Of Ginseng BZR Transcription Factor In Heterogeneity Plant Transformation

The BZR1 gene is a key transcription factor for brassinosteroids（BR）signal transduction,which directly feeds back and regulates the upstream components of the BR signaling pathway.BR is involved in regulating the elongation of plant stems and regulating the growth of plant roots.Gene function was studied by combining BZR1with transcription factors of the same family in most previous studies.BR was taken as the entry point in this paper,while studying Atbzr,the key rate-limiting enzyme gene Pg90B/724B that also played a role in brassinolide biosynthesis was introduced.And double mutations were constructed,in order to study the function of BZR1 gene.By observing the phenotypes of Atbzr and Atbzr-90b and measuring the physiological functions of the mutants in light and hormones under salt stress and different light intensities,the function of BZR gene was studied.The main experimental results were as follows:1.Plant expression vectors p RI201-AN-GUS-Pg BZR and p RI201-AN-Pg BZR-90B were successfully constructed.In addition,the plant expression vectors containing the BZR gene and the recombinant DNA BZR-90B were transferred into Agrobacterium tumefaciens LBA4404,and the wild-type Arabidopsis thaliana（Col.0）was successfully transformed.By kanamycin screening,Atbzr and Atbzr-90b T1generation plants were obtained.2.By phenotypic observation on Atbzr,it was found that compared with Wt Arabidopsis,Atbzr had a slower initial growth,but a faster later period and a shorter life cycle than Wt.Moreover,Atbzr can be divided into two phenotypes after 35 days,Atbzr-1（with large number of leaves,sharper tips,darker leaves,narrower leaves）,and Atbzr-2（with smaller number of leaves,sharper and rounder leaves,lighter leaves,wider leaves）.Furthermore,the flowering and fruiting time of Atbzr were earlier than Wt,and there was no significant difference in the number of seeds between them.As for Atbzr-90b,it had a shorter growth cycle than Wt,with upright leaves and no significant difference in the number of leaves,the flowering period and fruiting period of which were earlier,and the number of seeds was halved.3.The results of salt stress showed that different concentrations of salt stress（0,50,100,150,200 mmol/L Na Cl）treatment for 7 days,with the increase of Na Cl concentration,the whitening rate was gradually increased.In general,the whitening rate of Wt was the highest,followed by Atbzr,and finally Atbzr-90b.Besides,the Arabidopsis thaliana grown for 6-7 weeks was treated with 200 mmol/L Na Cl for 12 h,and the physiological indicators were detected.The results showed that the contents of soluble protein,soluble sugar,proline,chlorophyll,SOD,CAT,and POD were generally significantly higher in Atbzr than those in Wt and Atbzr-90b.The malondialdehyde content of Wt Arabidopsis thaliana was higher than that of Atbzr and Atbzr-90b.Atbzr was more resistant to salt than Atbzr-90b and wild type.Atbzr-90b was less damaged than Atbzr and Wt Arabidopsis.The results of physiological and biochemical measurements related to salt stress showed that transgenic Arabidopsis plants had better salt tolerance than non-transgenic wild-type Arabidopsis.4.The results of experiments on the effect of different light intensities on the mutants（5000-9000lx）showed that the overall intercellular CO₂ concentration Atbzr and Atbzr-90b were lower than Wt.And as for the transpiration rate,stomatal conductance,as well as photosynthetic rate Atbzr achieved highest,followed by Wt and Atbzr-90b respectively.For the determination of photosynthesis under different light intensities,Atbzr-90b was the most tolerant,followed by Atbzr-2,Atbzr-1,and Wt Arabidopsis.5.As for the effect of different hormones on the growth rate of mutants,It was found that in the BL-containing medium,Wt grew the fastest,the root growth of Atbzr was inhibited to a certain extent,the growth of stem was accelerated,and the growth of Atbzr-90b was basically unaffected.In the BRZ-containing medium,the growth of Atbzr-90b was basically unaffected,while the growth of Atbzr and Wt roots was significantly inhibited.In the medium containing IAA,the root growth of Wt was inhibited,whereas,the development of fibrous roots was promoted,the growth of Atbzr was inhibited,and the root growth rate of Atbzr-90b was slightly increased.In the medium containing 6-BA,the growth of Wt and Atbzr was inhibited,while the growth rate of Atbzr-90b was inhibited.