title: Comparative proteomics reveals a role for seed storage protein AmA1 in cellular growth, development, and nutrient accumulation.
abstract: Seed storage proteins are known to be utilized as carbon and nitrogen source for growing seedlings and thus are considered as potential candidates for nutritional improvement. However, their precise function remains unknown. We have earlier shown that ectopic expression of a seed storage protein, AmA1, leads to increase in protein besides high tuber yield in potato. To elucidate the AmA1-regulated molecular mechanism affecting increased protein synthesis, reserve accumulation, and enhanced growth, a comparative proteomics approach has been applied to tuber life-cycle between wild-type and AmA1 potato. The differential display of proteomes revealed 150 AmA1-responsive protein spots (ARPs) that change their intensities more than 2.5-fold. The LC-ESI-MS/MS analyses led to the identification of 80 ARPs presumably associated with cell differentiation, regulating diverse functions, viz., protein biogenesis and storage, bioenergy and metabolism, and cell signaling. Metabolome study indicated up-regulation of amino acids paralleling the proteomics analysis. To validate this, we focused our attention on anatomical study that showed differences in cell size in the cortex, premedullary zone and pith of the tuber, coinciding with AmA1 expression and localization. Further, we interrogated the proteome data using one-way analysis of variance, cluster, and partial correlation analysis that identified two significant protein modules and six small correlation groups centered around isoforms of cysteine protease inhibitor, actin, heat shock cognate protein 83 and 14-3-3, pointing toward AmA1-regulated overlapping processes of protein enhancement and cell growth perhaps through a common mechanism of function. A model network was constructed using the protein data sets, which aim to show how target proteins might work in coordinated fashion and attribute to increased protein synthesis and storage reserve accumulation in AmA1 tubers on one hand and organ development on the other.
authors.affiliation: Laboratory 104 and ‡Laboratory 105, National Institute of Plant Genome Research , Aruna Asaf Ali Marg, New Delhi 110067, India.
authors.forename: Lalit
authors.initials: L
authors.lastname: Agrawal
authors.forename: Kanika
authors.initials: K
authors.lastname: Narula
authors.forename: Swaraj
authors.initials: S
authors.lastname: Basu
authors.forename: Shubhendu
authors.initials: S
authors.lastname: Shekhar
authors.forename: Sudip
authors.initials: S
authors.lastname: Ghosh
authors.forename: Asis
authors.initials: A
authors.lastname: Datta
authors.forename: Niranjan
authors.initials: N
authors.lastname: Chakraborty
authors.forename: Subhra
authors.initials: S
authors.lastname: Chakraborty
mesh_terms: D000704:Analysis of Variance; D049109:Cell Proliferation; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D015180:Electrophoresis, Gel, Two-Dimensional; D055432:Metabolomics / Q000379:methods; D030821:Plants, Genetically Modified; D014176:Protein Biosynthesis / Q000235:genetics*; D040901:Proteomics / Q000379:methods*; D055314:Seed Storage Proteins / Q000235:genetics / Q000378:metabolism*; D036226:Seedlings / Q000254:growth & development*; D011198:Solanum tuberosum / Q000235:genetics* / Q000254:growth & development; D053719:Tandem Mass Spectrometry
chemical_list: D055314:Seed Storage Proteins