Fruit Proteome Research Articles

Spatiotemporal proteome expression during banana fruit development and ripening: elucidation of molecular insights

Banana is a highly perishable climacteric fruit, and its ripening process is notably fast, due to the modulation of several metabolic processes, including starch degradation, sugar accumulation, ethylene biosynthesis, cell wall modification, and others. However, most of the proteome studies on banana fruit are based on a single tissue type and are limited to either developmental or ripening stages. In contrast, the protein dynamics in the banana fruit during its development and ripening remain unclear. The function and morphology of each fruit tissue are different and ignoring the importance of tissue-specific studies obscures many specific functions. The current study focused on spatiotemporal proteome changes in banana peel and pulp tissues at several stages of fruit development and ripening. Most of the functionally categorized proteins were involved in the regulation of different biochemical and metabolic processes during banana ripening, i.e., starch and sugar metabolism, hormone regulation, cell wall modification, and transcription factors, representing the potential candidates involved in banana fruit development and ripening. We present a comprehensive banana fruit proteome data set by incorporating the expression of the proteins involved in diverse metabolic pathways, including two tissue types, and covering a range of fruit development and ripening stages. We have applied the bioinformatic algorithms to determine the interactions of identified proteins. Protein–protein interaction studies revealed that the two numbers of glycolysis pathway proteins namely, phosphoglucomutase and enolase, were found to interact more with other protein partners in the network. Our findings from this study not only provide an insight into the spatiotemporal modulations of the proteins during banana fruit development and ripening process but also open up the window for further validation of the identified key proteins to assign individual roles in fruit ripening and shelf-life, either through RNAi or genome editing tools.

The Fruit Proteome Response to the Ripening Stages in Three Tomato Genotypes.

The tomato is a horticultural crop that appears in various colors as it ripens. Differences in the proteome expression abundance of a tomato depend on its genotype and ripening stage. Thus, this study aimed to confirm the differences in changes in the proteome according to four ripening stages (green, breaker, turning, and mature) of three tomato genotypes, i.e., yellow, black, and red tomatoes, using a gel-based proteomic technique. The number of protein spots shown as two-dimensional electrophoresis (2-DE) gels differed according to tomato genotype and ripening stage. A total of 286 variant proteins were determined using matrix-assisted laser desorption-time of flight (MALDI-TOF) mass spectrometry (MS) analysis, confirming 233 identified protein functions. In three tomato genotypes in each ripening stage, grouping according to the Munich Information Center for Protein Sequences (MIPS) functional categories confirmed the variant proteins involved in the following: energy processes (21%); metabolism (20%); protein fate (15%); protein synthesis (10%); a protein with a binding function or cofactor requirement (8%); cell rescue, defense, and virulence (8%); cellular transport, transport facilitation, and transport routes (6%); the biogenesis of cellular components (5%); cell cycle and DNA processing (2%); others (5%). Among the identified protein spots in the function category, two proteins related to metabolism, four related to energy, four related to protein synthesis, and two related to interaction with the cellular environment showed significantly different changes according to the fruit color by the ripening stage. This study reveals the physiological changes in different types of tomatoes according to their ripening stage and provides information on the proteome for further improvement.

Unraveling Interactions of the Necrotrophic Fungal Species Botrytis cinerea With 1-Methylcyclopropene or Ozone-Treated Apple Fruit Using Proteomic Analysis.

Gray mold caused by the necrotrophic fungus Botrytis cinerea is one of the major postharvest diseases of apple fruit. The exogenous application of 1-methylcyclopropene (1-MCP) and gaseous ozone (O 3) is commonly used to ensure postharvest fruit quality. However, the effect of these treatments on the susceptibility of apple fruit to postharvest pathogens remains largely unknown. Herein, the effect of O 3 and 1-MCP treatments on the development of gray mold on apple fruit (cv. “Granny Smith”) was investigated. Artificially inoculated apple fruits, treated or not with 1-MCP, were subjected for 2 months to cold storage [0°C, relative humidity (RH) 95%] either in an O3-enriched atmosphere or in a conventional cold chamber. Minor differences between 1-MCP-treated and control fruits were found in terms of disease expression; however, exposure to ozone resulted in a decrease of disease severity by more than 50% compared with 1-MCP-treated and untreated fruits. Proteomic analysis was conducted to determine proteome changes in the mesocarp tissue of control and 1-MCP- or O3-treated fruits in the absence or in the presence of inoculation with B. cinerea. In the non-inoculated fruits, 26 proteins were affected by 1-MCP, while 51 proteins were altered by ozone. Dynamic changes in fruit proteome were also observed in response to B. cinerea. In O3-treated fruits, a significant number of disease/defense-related proteins were increased in comparison with control fruit. Among these proteins, higher accumulation levels were observed for allergen, major allergen, ACC oxidase, putative NBS-LRR disease resistance protein, major latex protein (MLP)-like protein, or 2-Cys peroxiredoxin. In contrast, most of these proteins were down-accumulated in 1-MCP-treated fruits that were challenged with B. cinerea. These results suggest that ozone exposure may contribute to the reduction of gray mold in apple fruits, while 1-MCP was not effective in affecting this disease. This is the first study deciphering differential regulations of apple fruit proteome upon B. cinerea infection and postharvest storage treatments, underlying aspects of host response related to the gray mold disease.

Comparative Proteomic Analysis of Cucumber Fruits Under Nitrogen Deficiency At the Fruiting Stage

Nitrogen deficiency is a major factor that affects the yield and quality of horticultural crops. Differentially expressed proteins were identified in cucumber fruit under nitrogen deficiency treatment, and are expected to be highly useful for dissecting carbon, nitrogen and ascorbate metabolism in cucumber and for improving nitrogen fertilizer utilization. Cucumber plants grown hydroponically in Hoagland solution were transferred to nitrogen-free conditions for 3 or 5 d after the blossom of female flowers. Fruit proteome profiles were assessed using two-dimensional electrophoresis. The relative expression of the genes encoding 50 selected differentially expressed proteins and 4 key enzymes in carbon metabolism was analyzed by qRT-PCR. Resulted showed that most of the identified differentially expressed proteins were mainly associated with carbon metabolism, amino acid biosynthesis, ascorbate metabolism, and proteasomes. Glucose phosphorylation was enhanced, while the pentose phosphate pathway was inhibited. Carbon metabolism and the synthesis of most amino acids was affected significantly, and ascorbate might be accumulated under nitrogen deficiency in cucumber fruit.

Comparative proteomic analysis of oil palm (Elaeis guineensis Jacq.) during early fruit development

To gain insights on protein changes in fruit setting and growth in oil palm, a comparative proteomic approach was undertaken to study proteome changes during its early development. The variations in the proteome at five early developmental stages were investigated via a gel-based proteomic technique. A total of 129 variant proteins were determined using mass spectrometric analysis, resulting in 80 identifications. The majority of the identified protein species were classified as energy and metabolism, stress response/defence and cell structure during early oil palm development representing potential candidates for the control of final fruit size and composition. Seven prominent protein species were then characterised using real-time polymerase chain reaction to validate the mRNA expression against the protein abundant profiles. Transcript and protein profiles were parallel across the developmental stages, but divergent expression was observed in one protein spot, indicative of possible post-transcriptional events. Our results revealed protein changes in early oil palm fruit development provide valuable information in the understanding of fruit growth and metabolism during early stages that may contribute towards improving agronomic traits. Biological significanceTwo-dimensional gel electrophoresis coupled with mass spectrometry approach was used in this study to identify differentially expressed proteins during early oil palm fruit development. A total of 80 protein spots with significant change in abundance were successfully identified and selected genes were analysed using real time PCR to validate their expression. The dynamic changes in oil palm fruit proteome during early development were mostly active in primary and energy metabolism, stress responses, cell structure and protein metabolism. This study reveals the physiological processes during early oil palm fruit development and provides a reference proteome for further improvements in fruit quality traits.

Proteomic analysis upon peach fruit infection with Monilinia fructicola and M. laxa identify responses contributing to brown rot resistance

Brown rot, caused by Monilinia spp., is a major peach disease worldwide. In this study, the response of peach cultivars Royal Glory (RG) and Rich Lady (RL) to infection by Monilinia fructicola or Monilinia laxa, was characterized. Phenotypic data, after artificial inoculations, revealed that ‘RL’ was relatively susceptible whereas ‘RG’ was moderately resistant to Monilinia spp. Comparative proteomic analysis identified mesocarp proteins of the 2 cultivars whose accumulation were altered by the 2 Monilinia species. Functional analysis indicated that pathogen-affected proteins in ‘RG’ were mainly involved in energy and metabolism, while, differentially accumulated proteins by the pathogen presence in ‘RL’ were involved in disease/defense and metabolism. A higher number of proteins was differentiated in ‘RG’ fruit compared to ‘RL’. Upon Monilinia spp. infection, various proteins were-down accumulated in ‘RL’ fruit. Protein identification by mass spectrometric analysis revealed that several defense-related proteins including thaumatin, formate dehydrogenase, S-formylglutathione hydrolase, CBS domain-containing protein, HSP70, and glutathione S-transferase were up-accumulated in ‘RG’ fruit following inoculation. The expression profile of selected defense-related genes, such as major latex allergen, 1-aminocyclopropane-1-carboxylate deaminase and UDP-glycoltransferase was assessed by RT-PCR. This is the first study deciphering differential regulations of peach fruit proteome upon Monilinia infection elucidating resistance responses.

ITRAQ-based quantitative proteomic analysis of peach fruit (Prunus persica L.) at different ripening and postharvest storage stages

Abstract To better understand the global and dynamic changes in peach (Prunus persica L. cv. Xiahui 8) fruit protein expression, an efficient and reliable proteomic technique, iTRAQ, was used to investigate peach fruit proteome from day -7 to day 8 during storage period at 25 ± 1 °C. A total of 387 proteins with more than 1.2-fold abundance changes were observed. These differentially expressed proteins (DEPs) are mainly related to 17 functional categories. DEPs in day -7 were mainly responsible for sugar and carbohydrate syntheses, protein translation, expression and modification, and maintenance of osmotic balance in high ion and material transport capacities and strong redox reaction environment. Harvesting induced the increase of (small) heat shock protein. Upon harvest, the increased level of respiration rates on day 4 reached the highest level. polygalacturonase (PG), pectase lyase (PL), pectinesterase (PE), chorismate mutase (CM), peptidyl-prolyl isomerase (PPIase) and phytoene synthase (PSY) showed increased abundances and reached a peak at day 6, which significantly positive correlation with 9-cis-epoxycarotenoid dioxygenase (NCED) protein, accelerated fruit softening and metabolism of protein, amino acid and lipid. The emergence of eukaryotic translation initiation factor 5A (EIF5A) on day 8 signified the intensification of apoptosis. Our study facilitated a comprehensive understanding of the complex proteomic reprograming and ripening-associated mechanisms that could be used for endeavors of breeding and postharvest processing to improve peach fruit quality.

Changes in the microsomal proteome of tomato fruit during ripening

The variations in the membrane proteome of tomato fruit pericarp during ripening have been investigated by mass spectrometry-based label-free proteomics. Mature green (MG30) and red ripe (R45) stages were chosen because they are pivotal in the ripening process: MG30 corresponds to the end of cellular expansion, when fruit growth has stopped and fruit starts ripening, whereas R45 corresponds to the mature fruit. Protein patterns were markedly different: among the 1315 proteins identified with at least two unique peptides, 145 significantly varied in abundance in the process of fruit ripening. The subcellular and biochemical fractionation resulted in GO term enrichment for organelle proteins in our dataset, and allowed the detection of low-abundance proteins that were not detected in previous proteomic studies on tomato fruits. Functional annotation showed that the largest proportion of identified proteins were involved in cell wall metabolism, vesicle-mediated transport, hormone biosynthesis, secondary metabolism, lipid metabolism, protein synthesis and degradation, carbohydrate metabolic processes, signalling and response to stress.

Cell wall proteome analysis of banana fruit softening using iTRAQ technology

Softening is important for quality formation in some climacteric fruits. The molecular mechanism underlying fruit softening is, however, not well understood. In this study, we performed a comparative cell wall proteomics analysis on pre-climacteric (P1) and post-climacteric (P2) banana fruit, corresponding to fruit at the mature green stage and softening ripening stage, respectively, using isobaric tags for relative and absolute quantitation (iTRAQ) technology. A total of 5230 proteins were identified in both sample groups, of which 928 were predicted to be secreted proteins. Of the secreted proteins, 162 were differentially expressed in P2 versus P1. The majority of these proteins had catalytic activity, binding activity, electron carrier activity and antioxidant activity. Compared with P1, P2 had 105 and 57 up- and down-regulated proteins, respectively. GO and KEGG-pathway analysis of these differentially expressed secreted proteins revealed that most were implicated in cell wall metabolism, stress and defense response, signaling, and protein metabolism and modification. Quantitative RT-PCR further validated some key differentially expressed secreted proteins associated with cell wall metabolism, stress and defense response, signaling and protein destination. Our results represent the first cell wall proteome of banana fruit and comprehensive proteomic study of banana fruit softening. SignificanceSoftening, which is the consequence of cell wall and turgor modification, is one of the most important factors determining banana fruit quality. The molecular mechanism regulating fruit softening in harvested banana is not currently well understood. In this study, we performed a comparative cell wall proteome analysis for pre-climacteric (P1) and post-climacteric (P2) banana fruit, corresponding to the mature green stage and softening ripening stage, respectively, using iTRAQ technology. We found 162 differentially expressed secreted proteins that were mainly implicated in cell wall metabolism, stress response and defense, signaling, and protein metabolism and modification. We have presented the first cell wall proteome of banana fruit and conducted a comprehensive proteomic study of banana fruit softening that will help to develop strategies to improve the sensorial quality and reduce post-harvest fruit losses.

Systematically quantitative proteomics and metabolite profiles offer insight into fruit ripening behavior in Fragaria × ananassa

Profound metabolic and proteomic changes involved in the primary and the secondary metabolism are required for the ripeness of fleshy fruit such as strawberries (Fragaria × ananassa). Here we present the quantitative proteomic profiling in parallel with metabolic and transcriptional profiling at five developmental stages of strawberry fruit ripening, and correlations between changes in representative metabolites and the abundance of related proteins were analyzed. Hierarchical clustering analysis of the quantitative proteomic profiling identified 143 proteins in strawberry fruit across five developmental stages. Meanwhile, both protein abundance and gene expression spanned a wide range of roles, such as the primary and the secondary metabolism, defense system, and response to stress stimuli. The decreased abundance of proteins contributed to the carbohydrate metabolism and the up-regulated expression of secondary biosynthetic proteins was found to be positively correlated with the accumulation of primary and secondary metabolites during strawberry development. Moreover, with the same annotations and high homology, the gene function of key genes involved in primary and secondary metabolism (FaTPI, FaPAL, FaMDH and FaME) was confirmed in Nicotiana via the transient expression assay, which provides further evidence for the role of those genes in metabolism of strawberry fruit. The results of the present study may serve as an important resource for the functional analysis of the proteome and offer new perspectives on regulation of fruit quality.

Proteomic fingerprinting of apple fruit, juice, and cider via combinatorial peptide ligand libraries and MS analysis.

Combinatorial peptide ligand libraries coupled to MS was applied to extensively map the proteome of apple fruit, and to detect its presence in commercial apple juice and cider to evaluate their authenticity and genuineness. Using the Uniprot_Malus database, 96 proteins were detected in apples, among which 30 proteins were specifically captured via combinatorial peptide ligand libraries. Next, three proteins, previously recognized in fruits, were found in apple juice, which were involved in cellular metabolism of fruit maturation and in allergenic reactions. On the other hand, only one Malus allergen was identified in cider beads eluate, demonstrating that the industrial processes did not prevent any negative effects in sensitive subjects. Thus, the present study not only increases the knowledge of the apple proteome but also offers a reliable analytical method to assess quality and genuineness of commercial products, which could be also used to inform consumers about the presence of allergens.

Cari p 1, a Novel Polygalacturonase Allergen From Papaya Acting as Respiratory and Food Sensitizer.

Papaya has been reported to elicit IgE-mediated hypersensitivity via pollen inhalation and fruit consumption. Certain papaya sensitive patients with food allergy were found to experience recurrent respiratory distresses even after quitting the consumption of fruits. This observation prompted us to investigate the allergens commonly present in fruits and pollen grains of papaya. A discovery approach consisting of immunoproteomic detection followed by molecular characterization led to the identification of a novel papaya allergen designated as Cari p 1. This allergen was detected as a 56 kDa IgE-reactive protein from pollen as well as fruit proteome through serological analysis. The protein was identified as an endopolygalacturonase by tandem mass spectrometry. Full length Cari p 1 cDNA was isolated from papaya pollen, cloned in expression vector, and purified as recombinant allergen. The recombinant protein was monomeric and displayed pectinolytic activity. Recombinant Cari p 1 reacted with IgE-antibodies of all the papaya sensitized patient sera. In addition to IgE-reactivity, rCari p 1 displayed allergenic activity by stimulating histamine release from IgE-sensitized granulocytes. CD-spectroscopy of rCari p 1 revealed the presence of predominantly β-sheet characters. The melting curve of the allergen showed partial refolding from a fully denatured state indicating the possible presence of conformational IgE-epitopes characteristic of inhalant allergens in addition to the linear IgE-epitopes of food allergens. The expression of this allergen in papaya fruits was detected by immunoblot with anti-Cari p 1 rabbit IgG and reconfirmed by PCR. In an in vivo mouse model, rCari p 1 exhibited a comparable level of inflammatory responses in the lung and duodenum tissues explaining the dual role of Cari p 1 allergen in respiratory sensitization via pollen inhalation and sensitization of gut mucosa via fruit consumption. Purified rCari p 1 can be used a marker allergen for component-resolved molecular diagnosis. Further immunological studies on Cari p 1 are warranted to design immunotherapeutic vaccine for the clinical management of papaya allergy.

The Plantain Proteome, a Focus on Allele Specific Proteins Obtained from Plantain Fruits.

Proteomics has been applied with great potential to elucidate molecular mechanisms in plants. This is especially valid in the case of non‐model crops of which their genome has not been sequenced yet, or is not well annotated. Plantains are a kind of cooking bananas that are economically very important in Africa, India, and Latin America. The aim of this work was to characterize the fruit proteome of common dessert bananas and plantains and to identify proteins that are only encoded by the plantain genome. We present the first plantain fruit proteome. All data are available via ProteomeXchange with identifier PXD005589. Using our in‐house workflow, we found 37 alleles to be unique for plantain covered by 59 peptides. Although we do not have access (yet) to whole‐genome sequencing data from triploid banana cultivars, we show that proteomics is an easily accessible complementary alternative to detect different allele specific SNPs/SAAPs. These unique alleles might contribute toward the differences in the metabolism between dessert bananas and plantains. This dataset will stimulate further analysis by the scientific community, boost plantain research, and facilitate plantain breeding.

Effect of postharvest nitric oxide treatment on the proteome of peach fruit during ripening

Nitric oxide (NO) is an important signalling molecule with diverse physiological functions in plants. This study investigated the protein profile changes of harvested peach fruit (Prunus persica L. cv. ‘Xiahui NO.5’) exposed to NO gas treatment. A total of 104 protein spots with abundance changes (>two-fold) in response to NO were observed, and the spots were further functionally classified into 7 categories, including energy and metabolism (30.77%), stress response and defence (25.00%), cell structure (8.65%), protein fate (8.65%), transport and transduction (6.73%), ripening and senescence (5.77%) and unclassified (13.46%). The effects of NO at the proteomic level in peach fruit are complicated and involve various biological processes. NO could induce an abundant increase of superoxide dismutase (SOD) and the ascorbate–glutathione cycle enzymes to promote the production of the complex 1-aminocyclopropane-1-carboxylic acid oxidase (ACO–NO–ACC), which affects the generation of ethylene. Also, NO could inhibit electron transport and oxygen consumption, enhance the tricarboxylic acid cycle (TCA) cycle and the glycolysis pathway, and NO could repress the loss of Ca2+ ions and other structural components that maintain the mechanical properties of cell structures.

Functional analysis of differentially expressed proteins in Chinese bayberry (Myrica rubra Sieb. et Zucc.) fruits during ripening

This study developed a proteome reference map of Myrica rubra fruits at the green, pink and red stages during ripening using two-dimensional gel electrophoresis (2-DE). Forty-six differentially expressed proteins were detected in the gel, of which 43 were successfully identified by matrix-assisted laser desorption ionization time-of-flight/time-of-flight mass spectrometry and protein database searching. We found that malic enzyme related to the decrease of organic acid acidity was up-regulated. The high abundance of pyruvate decarboxylase and alcohol dehydrogenase may contribute to fruit peculiar fragrant characteristics. Phenylalanine ammonia-lyase, chalcone synthase 11, UDP-glucose:flavonoid 3-O-glucosyltransferase, and anthocyanidin synthase, enzymes involved in the anthocyanin metabolic pathway, were all up-regulated. The physiological data agree with fruit proteome results. These findings provided insights into the metabolic processes and regulatory mechanisms during Chinese bayberry fruit ripening.

Dynamic changes in the date palm fruit proteome during development and ripening.

Date palm (Phoenix dactylifera) is an economically important fruit tree in the Middle East and North Africa and is characterized by large cultivar diversity, making it a good model for studies on fruit development and other important traits. Here in gel comparative proteomics combined with tandem mass spectrometry were used to study date fruit development and ripening. Total proteins were extracted using a phenol-based protocol. A total of 189 protein spots were differentially regulated (p≤0.05). The identified proteins were classified into 14 functional categories. The categories with the most proteins were ‘disease and defense’ (16.5%) and ‘metabolism’ (15.4%). Twenty-nine proteins have not previously been identified in other fleshy fruits and 64 showed contrasting expression patterns in other fruits. Abundance of most proteins with a role in abiotic stress responses increased during ripening with the exception of heat shock proteins. Proteins with a role in anthocyanin biosynthesis, glycolysis, tricarboxylic acid cycle and cell wall degradation were upregulated particularly from the onset of ripening and during ripening. In contrast, expression of pentose phosphate- and photosynthesis-related proteins decreased during fruit maturation. Although date palm is considered a climacteric species, the analysis revealed downregulation of two enzymes involved in ethylene biosynthesis, suggesting an ethylene-independent ripening of ‘Barhi’ fruits. In summary, this proteomics study provides insights into physiological processes during date fruit development and ripening at the systems level and offers a reference proteome for the study of regulatory mechanisms that can inform molecular and biotechnological approaches to further improvements of horticultural traits including fruit quality and yield.

Transcriptome and proteomic analysis of mango (Mangifera indica Linn) fruits

Here we used Illumina RNA-seq technology for transcriptome sequencing of a mixed fruit sample from 'Zill' mango (Mangifera indica Linn) fruit pericarp and pulp during the development and ripening stages. RNA-seq generated 68,419,722 sequence reads that were assembled into 54,207 transcripts with a mean length of 858bp, including 26,413 clusters and 27,794 singletons. A total of 42,515(78.43%) transcripts were annotated using public protein databases, with a cut-off E-value above 10(-5), of which 35,198 and 14,619 transcripts were assigned to gene ontology terms and clusters of orthologous groups respectively. Functional annotation against the Kyoto Encyclopedia of Genes and Genomes database identified 23,741(43.79%) transcripts which were mapped to 128 pathways. These pathways revealed many previously unknown transcripts. We also applied mass spectrometry-based transcriptome data to characterize the proteome of ripe fruit. LC-MS/MS analysis of the mango fruit proteome was using tandem mass spectrometry (MS/MS) in an LTQ Orbitrap Velos (Thermo) coupled online to the HPLC. This approach enabled the identification of 7536 peptides that matched 2754 proteins. Our study provides a comprehensive sequence for a systemic view of transcriptome during mango fruit development and the most comprehensive fruit proteome to date, which are useful for further genomics research and proteomic studies. Our study provides a comprehensive sequence for a systemic view of both the transcriptome and proteome of mango fruit, and a valuable reference for further research on gene expression and protein identification. This article is part of a Special Issue entitled: Proteomics of non-model organisms.

World’s Hottest Chilli Bhut Jolokia (Capsicum assamicum) Proteome Revealed: Comparative Proteomic Analysis of Differentially Expressed Proteins

With proteomic analysis including 2-DE, image analysis, and protein identification with MALDI-TOF/MS, an investigation aiming at a enhanced understanding of the whole fruit proteome and differentially expressed proteins and/or gene products was carried out with total fruit extracts from Bhut Jolokia (Capsicum assamicum) and less pungent Capsicum frutescens. A total of 107 dominant protein spots have been identified here using a 2-DE/MS technique. Among the identified proteins, 14 proteins exhibited qualitative difference with unique expression in Bhut Jolokia and 6 proteins showed quantitative differential expression alterations. Among the 6 differential proteins, one was down-regulated and 5 were up-regulated. Apart from the unique and differential proteins for which a cluster of orthologous groups (COG) could not be assigned (36.84%), most of the dominant unique and differentially expressed proteins were assigned to the COG of energy production and conversion (21.05%) and also carbohydrate transport and metabolism (21.05%). This differential protein expression was further confirmed for selected candidates by semi-quantitative RT PCR and quantitative real time PCR. This is the first proteomic description of world’s hottest chilli ‘Bhut Jolokia’ and a detailed functional analysis of these proteins would provide further information regarding complex cellular processes and mechanism of pungency in this important source of Capsaicinoids.

An extensive proteome map of tomato (Solanum lycopersicum ) fruit pericarp

Tomato (Solanum lycopersicum) is the model species for studying fleshy fruit development. An extensive proteome map of the fruit pericarp is described in light of the high-quality genome sequence. The proteomes of fruit pericarp from 12 tomato genotypes at two developmental stages (cell expansion and orange-red) were analyzed. The 2DE reference map included 506 spots identified by nano-LC/MS and the International Tomato Annotation Group Database searching. A total of 425 spots corresponded to unique proteins. Thirty-four spots resulted from the transcription of genes belonging to multigene families involving two to six genes. A total of 47 spots corresponded to a mixture of different proteins. The whole protein set was classified according to Gene Ontology annotation. The quantitative protein variation was analyzed in relation to genotype and developmental stage. This tomato fruit proteome dataset is currently the largest available and constitutes a valuable tool for comparative genetic studies of tomato genome expression at the protein level. All MS data have been deposited in the ProteomeXchange with identifier PXD000105.

Effect of Salinity and Calcium on Tomato Fruit Proteome

Salinity is a major abiotic stress that adversely affects plant growth and productivity. The physiology of the tomato in salty and nonsalty conditions has been extensively studied, providing an invaluable base to understand the responses of the plants to cultural practices. However few data are yet available at the proteomic level looking for the physiological basis of fruit development, under salt stress. Here, we report the effects of salinity and calcium on fruit proteome variations of two tomato genotypes (Cervil and Levovil). Tomato plants were irrigated with a control solution (3 dSm(-1)) or with saline solutions (Na or Ca+Na at 7.6 dSm(-1)). Tomato fruits were harvested at two ripening stages: green (14 days post-anthesis) and red ripe. Total proteins were extracted from pericarp tissue and separated by two-dimensional gel electrophoresis. Among the 600 protein spots reproducibly detected, 53 spots exhibited significant abundance variations between samples and were submitted to mass spectrometry for identification. Most of the identified proteins were involved in carbon and energy metabolism, salt stress, oxidative stress, and proteins associated with ripening process. Overall, there was a large variation on proteins abundance between the two genotypes that can be correlated to salt treatment or/and fruit ripening stage. The results showed a protective effect of calcium that limited the impact of salinization on metabolism, ripening process, and induced plant salt tolerance. Collectively, this work has improved our knowledge about salt and calcium effect on tomato fruit proteome.