title: A Comprehensive Analysis of Chromoplast Differentiation Reveals Complex Protein Changes Associated with Plastoglobule Biogenesis and Remodeling of Protein Systems in Sweet Orange Flesh.
abstract: Globular and crystalloid chromoplasts were observed to be region specifically formed in sweet orange (Citrus sinensis) flesh and converted from amyloplasts during fruit maturation, which was associated with the composition of specific carotenoids and the expression of carotenogenic genes. Subsequent isobaric tag for relative and absolute quantitation (iTRAQ)-based quantitative proteomic analyses of purified plastids from the flesh during chromoplast differentiation and senescence identified 1,386 putative plastid-localized proteins, 1,016 of which were quantified by spectral counting. The iTRAQ values reflecting the expression abundance of three identified proteins were validated by immunoblotting. Based on iTRAQ data, chromoplastogenesis appeared to be associated with three major protein expression patterns: (1) marked decrease in abundance of the proteins participating in the translation machinery through ribosome assembly; (2) increase in abundance of the proteins involved in terpenoid biosynthesis (including carotenoids), stress responses (redox, ascorbate, and glutathione), and development; and (3) maintenance of the proteins for signaling and DNA and RNA. Interestingly, a strong increase in abundance of several plastoglobule-localized proteins coincided with the formation of plastoglobules in the chromoplast. The proteomic data also showed that stable functioning of protein import, suppression of ribosome assembly, and accumulation of chromoplast proteases are correlated with the amyloplast-to-chromoplast transition; thus, these processes may play a collective role in chromoplast biogenesis and differentiation. By contrast, the chromoplast senescence process was inferred to be associated with significant increases in stress response and energy supply. In conclusion, this comprehensive proteomic study identified many potentially new plastid-localized proteins and provides insights into the potential developmental and molecular mechanisms underlying chromoplast biogenesis, differentiation, and senescence in sweet orange flesh.
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Yunliu
authors.identifier: http://orcid.org/0000-0002-7969-6754
authors.initials: Y
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Jiabin
authors.identifier: http://orcid.org/0000-0003-3893-1065
authors.initials: J
authors.lastname: Du
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Lun
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Zhiyong
authors.identifier: http://orcid.org/0000-0001-9343-3662
authors.initials: Z
authors.lastname: Pan
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Qiang
authors.identifier: http://orcid.org/0000-0003-1786-9696
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.).
authors.forename: Shunyuan
authors.identifier: http://orcid.org/0000-0003-1348-4879
authors.initials: S
authors.lastname: Xiao
authors.affiliation: Key Laboratory of Horticultural Plant Biology, Ministry of Education, College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, People's Republic of China (Y.Z., J.D., L.W., Z.P., Q.X., S.X., X.D.); andInstitute for Bioscience and Biotechnology Research, University of Maryland, Rockville, Maryland 20850 (S.X.) xxdeng@mail.hzau.edu.cn.
authors.forename: Xiuxin
authors.initials: X
authors.lastname: Deng
mesh_terms: D002338:Carotenoids / Q000378:metabolism; D060365:Chloroplast Proteins / Q000235:genetics / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D032084:Citrus sinensis / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D016000:Cluster Analysis; D018506:Gene Expression Regulation, Plant; D015151:Immunoblotting; D007553:Isotope Labeling / Q000379:methods; D046529:Microscopy, Electron, Transmission; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018087:Plastids / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D020543:Proteome / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D053719:Tandem Mass Spectrometry
chemical_list: D060365:Chloroplast Proteins; D010940:Plant Proteins; D020543:Proteome; D002338:Carotenoids