Increasing Drought And Salt Tolerance Of Caragana Intermedia By Transiently Expressing CiPP2C37-like In Leaves And Obtaining Its Transgenic Medicago Truncatula

Plants that distributes in nature often encounter abiotic stress,such as drought,cold,saline and alkaline,and these stresses caused serious effect on growth,development and even production of plants.Plants had formed a stable stress regulation system during the process of long-term mutual adaptation with the environment.Protein phosphorylation and dephosphorylation are important processes to regulate biological life activities,and PP2C,as an important protein phosphatase,is well known to be involved in plant stress response.Based on the previous studies about the CiPP2C-37-like transgenic Arabidopsis thaliana and the established leaf transient expression system of Caragana intermedia,we detected the function of CiPP2C-37-like under drought or salt stress used the transient expression system in this study,and tried to transform it into the model plant,Medicago truncatula,which is also a leguminosae species as C.intermedia.The main results are as follows:1.Enhanced drought and salt tolerance of C.intermedia with transient CiPP2C37-like expression in leaves was confirmed based on the system set up by Dr.Liu Kun,indicating that this gene could be used as the candidate gene for forage or crop breeding with improved stress tolerance.2.Taking the leaves of the genotype R108 as explant,the GUS reporter gene was firstly tested to transform into M.truncatula.Histochemical staining later had proved that the transformation was successful.3.During the transformation process CiPP2C37-like,callus inducing and shoot regeneration was compared by using the leaves,the main root,and the petiole of the sterile seedlings of M.truncatula as explants.The final results showed that the leaves were more suitable as explants than the petiole or the root segment.4.Under the condition of MS+5 mg/L 2,4-D+0.5 mg/L 6-BA+250 mg/L Cefotaxime+25 mg/L kanamycin+0.8%Agar,in dark,with the temperature of 24-25?,it is much suitable for CiPP2C3 7-like transgenic callus formation.And the rate of callus induction was 53.5%.5.For the CiPP2C37-like transgenic buds,medium recipe with MS+0.05 mg/L 6-BA+0.005 mg/L NAA+250 mg/L cefotaxime+0.8%Agar+2%sucrose,or with MS+250 mg/L cefotaxime+25 mg/L Kanamycin+0.8%Agar+2%sucrose,can induce bud differentiation efficiently.While clumps of buds also grow very well on the non-hormone-based differentiation medium.6.The CiPP2C37-like transgenic buds of M.truncatula had been identified successfully through PCR and sequencing.