Effect Of Chitosan Oligosaccharide With Different Molecular Weight On Biochemical Charactersand Differential Expression Of Proteins At Late Elongating In Sugarcane Leaves

Chitosan oligosaccharide(COS) that is β-1,4-oligomerization glucosamine,also named chitin oligosaccharide,which was obtained by degradation of chitosanis the only alkalinity polysaccharide in numerous natural sugar. Its bioactivity isbetter than the chitosan, with good water-solubility, high absorptivity and theunique bioactivity. So it can be used as plants growth regulator, enhancing thedefensive ability of plants, regulating human's body immune and inhibitingtumor, thus it has been used widely in medicine, agriculture and food areas.The present research work was carried out to investigate the changes ofbiochemical characters and proteins in sugarcane leaves at late elongating stagetreated with50mg/mL chitosan oligosaccharide solution of different molecularweight after10d. Then the content of the soluble carbohydrate, the content solubleproteins, the activity of POD enzyme, the content of chlorophyll in leaves ofsugarcane were determined, to analysis the effect of chitin oligosaccharide withdifferent molecular weight on the biochemical characters and proteins. The mainresults were summarized as follows:Compared with the control, the content of the soluble carbohydrate changeddifferently due to the different molecular weight of COS. The content of thesoluble carbohydrate was decreased11.5%under the treatment of COS with themolecular weight of32179.But the soluble carbohydrate had no significantchange sprayed under the treatment of COS with the molecular weight of22936and8372.On the other hand the content of soluble protein decreased significantly(P<0.05) under the COS treatment compared with the control, while the mostsignificant effects were sprayed with the treatment of COS with the molecularweight of32179and induced the soluble protein decreased by11.9%.The activity of POD increased by12.3%under the treatment of COS withthe molecular weight of32179, but decreased with the molecular weight of22936and8372. The content of chlorophyll a increased and chlorophyll b decreased under thetreatment of COS compared with the control(P<0.05). But the content of totalchlorophyll had no significant change.From the above results we can conclude that the effect of the chitosanoligosaccharide with molecular weight of32179on sugarcane at late elongatingstage is relatively significant. The results shows that the chitosan oligosaccharidewith molecular weight of32179most probably is effective for sugar accumulationduring sugar accumulation stage.Proteins in sugarcane leaves were extracted by phenol extraction, the2-DEanalysis showed that compared with the control, there are14differental proteinsunder treatment of COS with the molecular weght of32179,4protein spots wereup-regulated and10protein spots were down-regulated; under the treatment ofCOS with the molecular weight of22936, there are51differential proteins,6protein spots were up-regulated and45protein spots were down-regulated.58differential proteins under the treatment of COS with the molecular weight of8372,3protein spots were up-regulated and55protein spots were down-regulated. Thethree different molecular weight COS induced5same differential proteins, whichwere3405,4601,6303,7301and7601.So we can concluded that, COS can induceddifferential expression of proteins in sugarcane leaves, but the differential isdifferent along with the COS molecular weight, and the down-regulated proteinsalways more than the up-regulated proteins among the induced proteins. After apreliminary analysis of their relative molecular weight, they are about31.6kDa,38kDa,,31kDa,28.8kDa,38.9kDa respectively, the pI are5.6,5.8,6.4,6.4,6.5respectively.