Differential Proteomics Analysis In Roots Of Flue-cured Tobacco Before And After Topping

The content of nicotine is an important indicator to assess tobacco quality. Topping,one of planting techniques is the largest influence to nicotine content.For a long time, tobacco researchers have done a lot of research work on cultivation,soil and fertilizers so as to solve the high content of nicotine in upper leaves,but can not solve the problem fundamentally.As nicotine is an important secondary product in tobacco,the synthesis and accumulation process is a very complex network control.Thus the regulation of the nicotine synthesis and accumulation of protein dynamics is researched by proteomics method before and after topping,and reveals the molecular basis on nicotine content by topping with great potential.Based on tobacco(Nicotiana tabacum L.)root tissues for materials,the study of protein extraction,the quantity of sample on 2-DE and the time of isoelectric focusing were analyzed,the suitable 2D-PAGE parameters of tobacco root tissue protein were established,the 2-DE coagulation plastic map with better quality and repeatability were got.The results analyzed by Image Master 2D software showed that there were about 500 detectable spots which distributed PI 3-10,molecular weight 97-14KD.The proteins which had same molecular weight but different isoelectric point were separated distinctly,most of them distributed in molecular weight 25-66KD, PI 4-6.5.Spots matched by comparison,the differential protein expression between topping,JA treatment and control were separated clearly.The up proteins in topping and JA treated were thirteen and twenty-six,and there were three common spots,the down proteins were five and six, and there was two common spot.There were eight and five differential expressed spots respectively,and there were four common spots.With direct MALDI-TOF mass spectrometry analysis and protein database searching,four protein spots were identified.Which were sorbitol-6-phosphate dehydrogenase,carbamoyl phosphate transferase,spermidine/spermine synthase enzyme and mature K.The study of these proteins may be involved in regulating the mechanism of nicotine synthesis and accumulation was discussed.The results of difference proteomics analysis show that the change of storeroom between fountainhead is the main reason of the increase of the nicotine synthesis before and after topping.And the results hint that JA signal conduction approach play an importent role in the nicotine synthesis and accumulation before and after topping,not the only regulationt factor.