Expression Analysis Of Maize C₄Key Enzyme（Phosphoenolpyruvate Carboxylase、pyruvate Orthophosphate Dikinase、Nadp-Malic Enzyme） Genes In Arabidopsis

In this experiment, we introduced to arabidopsis with pepc, ppdk and nadp-me,which had been cloned by our lab, and geted transgenic plants. The physiologicalcharacteristics under drought stress and the photosynthetic ability of transgenicArabidopsis were studied. The studies show the follwing results:1. We introduced the PEPC, PPDK and NADP-ME to arabidopsis byAgrobacterium-mediated transformation, and obtained137transgentic plants byBasta-tolerant. The PCR result showed that we obtained23NADP-ME transgentic lines,3PEPC+NADP-ME transgentic lines,9PPDK+NADP-ME transgentic lines and3PEPC+PPDK+NADP-ME transgentic lines.2. The net photosynthetic rate and chlorophyll content of14transgenic lines weremeasured, the results showed that net photosynthetic rate of six single gene transgenicstrains PEPC （PC73, PC65）, PPDK （PK26, PK36） and NADP-ME （PM1, PM7） wasincreased8%,21%,22%,11%,14%and16%than that of control, the content ofchlorophyll in rosette leaves was increased2%,14%,25%,8%,9%and28%respectively;the net photosynthetic rate of six double gene transgenic strains PEPC+PPDK （PCK6,PCK110）, PEPC+NADP-ME （PCM01, PCM03）, PPDK+NADP-ME （PKM03, PKM05）were increased24%,26%,26%,27%,21%and31%, the content of chlorophyll in rosetteleaves was increased27%,51%,18%,55%,45%and54%respectively;and about of twothree gene transgenic strains PEPC+PPDK+NADP-ME （PCKM01, PCKM03）, the netphotosynthetic rate was36%and26%higher than those of the controls., the content ofchlorophyll in rosette leaves was increased43%and55%.The change trend of rosette leafchlorophyll content consistent with that of net photosynthetic rate.The results showed thatthe transgenic corn’s C₄key enzyme could increase the photosynthetic rate of Arabidopsisthaliana, double transgenic is better than the single transgenic, and three transgenic isbetter than double transgenic.3. We studyed the Physiological characteristics of transgenic lines under osmoticstress conditions. Under stress condition, F0was increased and Fv/Fm was decreased, theincreased range of wild type was biggest which was20.4%, t Fv/Fm of wild type wasminimum which was0.78.The average relative root lengths in line pepc, ppdk, pepc+ppdk were1.44,1.48,1.51times of those in wild type plants under stress condition,respectively. In the condition of drought stress for25days and following by re-water for5days, the seedling death rates of lines pepc, ppdk, and pepc+ppdk were12%,13%, and7%,respectively, which were extremely significantly lower than that of wild plants（87%）.The average chlorophyll contents in line pepc, ppdk, pepc+ppdk were1.13,1.15,1.23times of those in wild type plants, respectively. The soluble sugar and soluble proteincontents in transgenic lines were higher than wild plants, the average values are1.03,1.16,1.24and1.01,1.11,1.15folds, respectively. The malondialdehyde content lower thanwild plants, the average values are0.94,0.90and0.84of those in wild plants.