| Sweet potato (Ipomoea batatas) is widely grown in the world, the total output is in theforefront of the world’s food production, its production is next to rice, wheat and maize inChina. Sweet potatoe not only can be used as a traditional food crops and starch extractionmaterial, but also can be used as feed or nutritional, healthy and diet food, stems and leavesvegetables. In addition, sweet potato as drought stress tolerance fringe plants, energy plantsfor the production of ethanol and bio-diesel, environmentally friendly renewable energy,aroused people’s attention in recent yearsSOD and APX are two key enzymes in scavenging reactive oxygen species, Oxygenradical can be converted to hydrogen peroxide by SOD, and then be cleared throughAsA-2GSH circulation under the effect of APX.On the one hand, by measuring the physiological changes of sweet potato seedling underthe10%PEG short-term osmotic stress conditions, this research further study thephysiological response differences of Cu/Zn SOD and APX cotransgenic sweet potato (T) andnon-transgenic sweet potato (NT). On the other hand, after osmotic stress treatment for24hours, explore sweet potato root proteins differentially expressed mechanism by means oftwo-dimensional electrophoresis and matrix-assisted laser desorption time-of-flight massspectrometry. The main findings are as follows:1. After treated with10%PEG stress: There was no obvious hydrogen peroxide damagecharacteristics; Sweet potato water retention improved in vitro leaf, but there was no obviousrelationship with transferring Cu/Zn SOD and APX gene; Transgenic sweet potato canmaintain higher root water conductivity; The ABA content in NT was always higher than Tbut root malondialdehyde content was totally opposed in different water stress time; Thehighest soluble sugar content values appeared after3hours and24hours drought stress in Tand NT, but T changed more quickly; T accumulated more free proline than NT. Physiologicaland biochemical results suggest that over-expression of Cu/Zn SOD and APX gene couldimprove the ability of short-term mild drought stress resistance of sweet potato.2. More than880protein spots were reproducibly detected,34protein spots were significantly expressed in two treatments with1.5times compared with controls through t-test(P <0.05, Fold>1.5, Quality>80). The34protein spots were analyzed by matrix-assistedlaser desorption/ionization-time of flight mass spectrometry,23has been effectivelyidentified among them. However,10proteins was co-upregulated or co-downregulated in Tand NT (beta subunit of ATP synthase F1, enolase,26S proteasome regulatory subunit6, ACCsynthase), whereas13proteins was differentially expressed in T and NT (enolase, ribulose-1,5-bisphosphate carboxylase/oxygenase binding protein beta subunit and sucrose synthase) intotal23protein spots. The results show that,10co-upward or co-downward expression of theproteins were generally responsive protein to short-term osmotic stress in sweet potato,reflecting a common response mechanism of T and NT roots in short-term osmotic stress.Additionally, The other13different expression proteins in T and NT indicated that thetransgenic sweet potato roots protein presented specific performance in the short-termosmotic stress response mechanism. |
