The Proteomics Study Of P.alba×P.glandulosa Stem Cambium During Chilling Induced Dormancy Release

Plant vascular cambium is an important feature for the woody plants growing in temperate zone distinction from other annual or perennial herb plant.And the forest tree cambium tissue can continuously form new xylem and phloem,which can make woody plant growing strongger and higher.Dormancy is dormancy is an effective strategy of plant for surviving the winter stress.Forest could be acclimatized the seasonal changing depending on dormancy,which is an important mechanism.However,the mechanism of dormancy maintenance and release remains poorly being understood.With the Genome Sequencing completing,poplar has been widely used as an important model species for woody plants.Therefore,in this study,we took poplar cambium as the object by using semi-thin section technology,and isobaric tags for relative and absolute quantitation(iTRAQ)combined with LC-MS/MS technology to analyze the changes in poplar during dormancy and dormancy release cambium induced by chilling.To a better understanding the regulatory mechanism of tree dormancy maintaining and dormancy release by methods of plant anatomy,and amounts of metabolic network results obtained from proteomics data,as well as providing new information regarding the regulation mechanisms of dormancy maintenance and its release in trees.The result of semi-thin section showed that the cambium cells were tightly arranged,with smaller volume and decreased cell layer number,containing abundant storage materials in dormancy stage.While poplar cambium tissue from dormancy release recovering to activity stage,the volume of cambium cells became enlarged,with the increased cells layer number.And the storage materials in cambium cells was gradually disappeared.A total of 3789 proteins were identified in poplar cambial tissues,1996 of them were significantly altered during the dormancy release.Most of the altered proteins involved in signaling,phytohormone,energy metabolism,stress and secondary metabolism by functional analysis.Our data shows that the lipid metabolism proteins changed significantly both in the release stage of eco-dormancy and endo-dormancy,while the changes of carbohydrate metabolism proteins were mainly in endo-dormancy release stage.Moreover,histochemical results were consistent with the proteomic data.Our histochemical staining results had showed that the lipid drops changed significantly both in the eco-dormancy and endo-dormancy release stages.While the changes of soluble saccharide and starch were mainly in the endo-dormancy release stage.Using QRT-PCR to verificate the level of a set of energy metabolism related protein gene expression confirmed the results of the proteomic data.Histochemical staining results further verify the energy metabolism in the process of dormancy release,include sugar,starch,and lipid changes trends,which could affirmate of the results of proteomics in another way.All these results reveal diverse stage-specific metabolism changes during the dormancy-release process induced by chilling in poplar,which provided new information regarding the regulation mechanisms of dormancy maintenance and its release in trees.