Proteomic analysis reveals the diversity and complexity of membrane proteins in chickpea (Cicer arietinum L.)

Background Compartmentalization is a unique feature of eukaryotes that helps in maintaining cellular homeostasis not only in intra- and inter-organellar context, but also between the cells and the external environment. Plant cells are highly compartmentalized with a complex metabolic network governing various cellular events. The membranes are the most important constituents in such compartmentalization, and membrane-associated proteins play diverse roles in many cellular processes besides being part of integral component of many signaling cascades. Results To obtain valuable insight into the dynamic repertoire of membrane proteins, we have developed a proteome reference map of a grain legume, chickpea, using two-dimensional gel electrophoresis. MALDI-TOF/TOF and LC-ESI-MS/MS analysis led to the identification of 91 proteins involved in a variety of cellular functions viz., bioenergy, stress-responsive and signal transduction, metabolism, protein synthesis and degradation, among others. Significantly, 70% of the identified proteins are putative integral membrane proteins, possessing transmembrane domains. Conclusions The proteomic analysis revealed many resident integral membrane proteins as well as membrane-associated proteins including those not reported earlier. To our knowledge, this is the first report of membrane proteome from aerial tissues of a crop plant. The findings may provide a better understanding of the biochemical machinery of the plant membranes at the molecular level that might help in functional genomics studies of different developmental pathways and stress-responses

Characterization of the secretome of chickpea suspension culture reveals pathway abundance and the expected and unexpected secreted proteins

The secretome of an organism is defined as a set of secreted proteins that encompasses all proteins exported to the extracellular space. To better understand the chickpea secretome, we used callus culture to isolate and identify secreted proteins as a step toward determining their functions. Proteins in the extracellular media of the suspension culture were examined using SDS-PAGE and mass spectrometry (LC–MS/MS). Proteomic analysis led to the identification of 773 proteins, presumably involved in a variety of functions including metabolism, signal transduction, transport, and cell defense, in addition to maintaining redox status of extracellular space. Bioinformatic analysis confirmed 724 proteins, accounting for 94% of the identified proteins, as constituents of the secretome. Analysis of the secretome revealed the presence of several proteins of unknown function and a large number of classical and nonclassical secreted proteins. This represents the first comprehensive secretome of a legume genome, which is yet to be sequenced. Comparative analysis of the chickpea secretome with those of Medicago, Arabidopsis, and rice revealed that the majority of identified proteins are seemingly species-specific. This study demonstrates that characterization of the chickpea secretome in vitro can be used to identify secreted proteins, which has implications for systems biology research

Nuclear phosphoproteome of developing chickpea seedlings (Cicer arietinum L.) and protein-kinase interaction network

Nucleus, the control centre of eukaryotic cell, houses most of the genetic machineries required for gene expression and their regulation. Post translational modifications of proteins, particularly phosphorylation control a wide variety of cellular processes but its functional connectivity, in plants, is still elusive. This study profiled the nuclear phosphoproteome of a grain legume, chickpea, to gain better understanding of such event. Intact nuclei were isolated from 3-week-old seedlings using two independent methods, and nuclear proteins were resolved by 2-DE. In a separate set of experiments, phosphoproteins were enriched using IMAC method and resolved by 1-DE. The separated proteins were stained with phosphospecific Pro-Q Diamond stain. Proteomic analyses led to the identification of 107 putative phosphoproteins, of which 86 were non-redundant. Multiple sites of phosphorylation were predicted on several key elements, which included both regulatory and functional proteins. The analysis revealed an array of phosphoproteins, presumably involved in a variety of cellular functions, viz., protein folding (24%), signalling and gene regulation (22%), DNA replication, repair and modification (16%), and metabolism (13%), among others. These results represent the first nucleus-specific phosphoproteome map of a non-model legume, which would provide insights into the possible function of protein phosphorylation in plants

Proteomic analysis reveals the diversity and complexity of membrane proteins in chickpea (<it>Cicer arietinum</it> L.)

Abstract Background Compartmentalization is a unique feature of eukaryotes that helps in maintaining cellular homeostasis not only in intra- and inter-organellar context, but also between the cells and the external environment. Plant cells are highly compartmentalized with a complex metabolic network governing various cellular events. The membranes are the most important constituents in such compartmentalization, and membrane-associated proteins play diverse roles in many cellular processes besides being part of integral component of many signaling cascades. Results To obtain valuable insight into the dynamic repertoire of membrane proteins, we have developed a proteome reference map of a grain legume, chickpea, using two-dimensional gel electrophoresis. MALDI-TOF/TOF and LC-ESI-MS/MS analysis led to the identification of 91 proteins involved in a variety of cellular functions viz., bioenergy, stress-responsive and signal transduction, metabolism, protein synthesis and degradation, among others. Significantly, 70% of the identified proteins are putative integral membrane proteins, possessing transmembrane domains. Conclusions The proteomic analysis revealed many resident integral membrane proteins as well as membrane-associated proteins including those not reported earlier. To our knowledge, this is the first report of membrane proteome from aerial tissues of a crop plant. The findings may provide a better understanding of the biochemical machinery of the plant membranes at the molecular level that might help in functional genomics studies of different developmental pathways and stress-responses.</p

OsAlba1, a dehydration-responsive nuclear protein of rice (Oryza sativa L. ssp. indica), participates in stress adaptation

Alba proteins have exhibited great functional plasticity through the course of evolution and constitute a superfamily that spans across three domains of life. Earlier, we had developed the dehydration-responsive nuclear proteome of an indica rice cultivar, screening of which led to the identification of an Alba protein. Here we describe, for the first time, the complete sequence of the candidate gene OsAlba1, its genomic organization, and possible function/s in plant. Phylogenetic analysis showed its close proximity to other monocots as compared to dicot Alba proteins. Protein–DNA interaction prediction indicates a DNA-binding property for OsAlba1. Confocal microscopy showed the localization of OsAlba1–GFP fusion protein to the nucleus, and also sparsely to the cytoplasm. Water-deficit conditions triggered OsAlba1 expression suggesting its function in dehydration stress, possibly through an ABA-dependent pathway. Functional complementation of the yeast mutant &#916;Pop6 established that OsAlba1 also functions in oxidative stress tolerance. The preferential expression of OsAlba1 in the flag leaves implies its role in grain filling. Our findings suggest that the Alba components such as OsAlba1, especially from a plant where there is no evidence for a major chromosomal role, might play important function in stress adaptation

Additional file 4: Table S2. of CicerTransDB 1.0: a resource for expression and functional study of chickpea transcription factors

Distribution of TF family genes across the chromosomes. (PDF 42 kb

Characterisation of the nuclear proteome of a dehydration-sensitive cultivar of chickpea and comparative proteomic analysis with a tolerant cultivar

Water deficit or dehydration hampers plant growth and development, and shrinks harvest size of major crop species worldwide. Therefore, a better understanding of dehydration response is the key to decipher the regulatory mechanism of better adaptation. In recent years, nuclear proteomics has become an attractive area of research, particularly to study the role of nucleus in stress response. In this study, a proteome of dehydration-sensitive chickpea cultivar (ICCV-2) was generated from nuclei-enriched fractions. The LC-MS/MS analysis led to the identification of 75 differentially expressed proteins presumably associated with different metabolic and regulatory pathways. Nuclear localisation of three candidate proteins was validated by transient expression assay. The ICCV-2 proteome was then compared with that of JG-62, a tolerant cultivar. The differential proteomics and in silico analysis revealed cultivar-specific differential expression of many proteins involved in various cellular functions. The differential tolerance could be attributed to altered expression of many structural proteins and the proteins involved in stress adaptation, notably the ROS catabolising enzymes. Further, a comprehensive comparison on the abiotic stress-responsive nuclear proteome was performed using the datasets published thus far. These findings might expedite the functional determination of the dehydration-responsive proteins and their prioritisation as potential molecular targets for better adaptation

Additional file 3: Figure S2. of CicerTransDB 1.0: a resource for expression and functional study of chickpea transcription factors

A bar chart showing distribution of transcription factors in chickpea genome on individual chromosomes and line chart showing average density of transcription factors in each chromosome. The data shows count of all TF types. Individual family distribution graph has been included in the database website. (PDF 26 kb