title: Proteomic changes in rice leaves during development of field-grown rice plants.
abstract: Of the numerous factors affecting rice yield, how solar radiation is transformed into biomass through rice leaves is the most important. We have analyzed proteomic changes in rice leaves collected from six different developing stages (vegetative to ripening). We studied protein expression profiles of rice leaves by running two-dimensional gel electrophoresis. Differential protein expression among the six phases were analyzed by image analysis, which allowed the identification of 49 significantly different gel spots. The spots were further verified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry, in which 89.8% of them were confirmed to be rice proteins. Finally, we confirmed some of the interesting rice proteins by immunoblotting. Three major conclusions can be drawn from these experimental results. (i) Protein expression in rice leaves, at least for high or middle abundance proteins, is attenuated during growth (especially some chloroplast proteins). However, the change is slow and the expression profiles are relatively stable during rice development. (ii) Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), a major protein in rice leaves, is expressed at constant levels at different growth stages. Interestingly, a high ratio of degradation of the RuBisCO large subunit was found in all samples. This was confirmed by two approaches, mass spectrometry and immunoblotting. The degraded fragments are similar to other digested products of RuBisCO mediated by free radials. (iii) The expression of antioxidant proteins such as superoxide dismutase and peroxidase decline at the early ripening stage.
authors.affiliation: Beijing Genomics Institute, Chinese Academy of Sciences, Beijing, China.
authors.forename: Caifeng
authors.initials: C
authors.lastname: Zhao
authors.forename: Jingqiang
authors.initials: J
authors.lastname: Wang
authors.forename: Mengliang
authors.initials: M
authors.lastname: Cao
authors.forename: Kang
authors.initials: K
authors.lastname: Zhao
authors.forename: Jianmin
authors.initials: J
authors.lastname: Shao
authors.forename: Tingting
authors.initials: T
authors.lastname: Lei
authors.forename: Jianning
authors.initials: J
authors.lastname: Yin
authors.forename: Gradford G
authors.initials: GG
authors.lastname: Hill
authors.forename: Ningzhi
authors.initials: N
authors.lastname: Xu
authors.forename: Siqi
authors.initials: S
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000737:chemistry; D015153:Blotting, Western; D002736:Chloroplasts / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005609:Free Radicals; D018506:Gene Expression Regulation, Plant; D006863:Hydrogen-Ion Concentration; D007091:Image Processing, Computer-Assisted; D015151:Immunoblotting / Q000379:methods; D013058:Mass Spectrometry; D012275:Oryza / Q000235:genetics* / Q000378:metabolism*; D010544:Peroxidases / Q000737:chemistry; D018515:Plant Leaves / Q000378:metabolism*; D010940:Plant Proteins / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D040901:Proteomics / Q000379:methods*; D012273:Ribulose-Bisphosphate Carboxylase / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013482:Superoxide Dismutase / Q000737:chemistry; D013997:Time Factors; D014357:Trypsin / Q000737:chemistry
chemical_list: D000975:Antioxidants; D005609:Free Radicals; D010940:Plant Proteins; D011506:Proteins; D010544:Peroxidases; D013482:Superoxide Dismutase; D014357:Trypsin; D012273:Ribulose-Bisphosphate Carboxylase