| Cassava(Manihot esculenta Crantz)belongs to Manihot genus,Euphorbiaceae family.Cassava is an important starchy crop and the main source of food for nearly 800 million people living in tropical and subtropical regions.It can also be used as feed and important industrial raw material,and medicine,papermaking,textile,and chemical industry and so on.Therefore,it's crucial for us to study the protein regulation mechnism of starch synthesis,which has significant importance for improving quality and breeding new cassava varieties with higher cassava starch,and provides theoretical guidance for agricultural product.In this study,two wild species M.glaziovii(Glaziovii)(MG)and M.esculenta ssp flabellifolia(W14),and two cultivated cassava M.esculenta cv.SC No.8(SC8)and SC205,which planted for 10 months,were used as materials.The whole proteins of 4 species were analyzed by i TRAQ technique.Understanding the protein regulation mechanism of starch accumulation and excavation important proteins which affect starch metabolism can provide theoretical support for selecting new cassava varieties with high yield and high starch in wild species and cultivation.The main results are as follows:1.The i TRAQ technology was used for protein identification and the relative quantitative analysis.We got 402147 pieces of total spectra,of which matched 45836 pieces of spectra to bank by Mascot software;we got 33087 pieces of unique spectra,21309 peptides,16827 unique peptides.A total of 5021 cassava proteins were identified.The relative molecular weight of the protein was mainly concentrated in 10~80 k Da,and the length of the peptide was mainly concentrated in 7~102 amino acid residues.2.Blastx with COG database,proteins were divided into 24 categories according to function.The number of general function prediction only proteins were the most in the total protein(826),energy production and conversion(331),amino acid transport and metabolism(331),carbohydrate transport and metabolism(351),translation,ribosomal structure and biogenesis(361),posttranslational modification,protein turnover,chaperones(473),these pathways also had more proteins.The proteins accroding to GO can be divided into three categories: biological processes,cellular components and molecular processes,which has 55 branches.The proteins involved in cell and cellular component were largest,23.36% and 23.36%,respectively.Inmolecular function,proteins involved in binding and catalytic activity were highest,40.93% and45.05%,respectively.The proteins involved in cellular processes and metabolic pathway were the largest in biological processes,16.22% and 16.54%,respectively.3.KEGG database was used as a reference,differential proteins in starch accumulation were annotated.According to the metabolic pathways,proteins datas can be classifide into 124 categories,and they were divided into carbon metabolism and energy metabolism,photosynthesis related metabolism,amino acid metabolism,DNA and RNA-related metabolism,protein-related metabolism,cofactor and vitamin metabolism,signal transduction metabolism,lipid metabolism,defense and transport metabolism and other secondary metabolic 10 categories,with 18,2,18,10,11,9,2,13,8,22 metabolic pathways,respectively,and 196,21,149,89,235,57,19,50,65,78 differential proteins,respectively.4.The differential expression analysis of 4 cassava proteomes was carried out with W14 as the control.There were 670 differential proteins between MG and W14,of which 343 were up-regulated and 327 were down-regulated.There were 729 differential proteins between SC8 and W14,of which 347 were up-regulated and 382 were down-regulated.There were 283 differential proteins between SC205 and W14,of which 143 were up-regulated and 140 were down-regulated.5.Based on the network of protein-protein interaction analyzed from the differential proteins in i TRAQ using the on-line software STRING,we find that glutamate synthase(NADH/NADPH)(141),acetyl-Co A carboxylase(141),glutamate synthase(ferredoxin)(130),ATP citrate(pro-S)-lyase(122),urease(104),Glutamyl-gamma-semialdehyde dehydrogenase(97),methionyl-t RNA synthetase(88),molecular chaperone Dna K(82),malate dehydrogenase(79),enolase(73),(Ref Seq)translation elongation factor Tu(73),Hsc70(69)had more lines.The glutamate synthase(NADH/NADPH)and urease was the same,the Dna K and(Ref Seq)translation elongation factor Tu was down-regulation in cultivar of cassava,other proteins were up-regulation.These proteins may play an important role in the starch accumulation.6.Nice proteins were verified using q RT-PCR,the result showed some differences compared with protein expressed level from i TRAQ. |
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