Proteomic analysis of papaya fruit ripening using 2DE-DIGE

Papayas have a very short green life as a result of their rapid pulp softening as well as their susceptibility to physical injury and mold growth. The ripening-related changes take place very quickly, and there is a continued interest in the reduction of postharvest losses. Proteins have a central role in biological processes, and differential proteomics enables the discrimination of proteins affected during papaya ripening. A comparative analysis of the proteomes of climacteric and pre-climacteric papayas was performed using 2DE-DIGE. Third seven proteins corresponding to spots with significant differences in abundance during ripening were submitted to MS analysis, and 27 proteins were identified and classified into six main categories related to the metabolic changes occurring during ripening. Proteins from the cell wall (alpha-galactosidase and invertase), ethylene biosynthesis (methionine synthase), climacteric respiratory burst, stress response, synthesis of carotenoid precursors (hydroxymethylbutenyl 4-diphosphate synthase, GcpE), and chromoplast differentiation (fibrillin) were identified. There was some correspondence between the identified proteins and the data from previous transcript profiling of papaya fruit, but new, accumulated proteins were identified, which reinforces the importance of differential proteomics as a tool to investigate ripening and provides potentially useful information for maintaining fruit quality and minimizing postharvest losses. (C) 2011 Elsevier B.V. All rights reserved.

Oxidative processes during 'Golden' papaya fruit ripening

'Golden' papayas at maturity stage 1 (15% yellow skin) were chosen to study selected oxidative processes, the activity of antioxidant enzymes and lipid peroxidation in storage at 22°C, during the ripening of the fruit. An increase in ethylene production was observed on the second day of storage and it was followed by an increase in respiration. An increased activity of catalase, glutathione reductase and ascorbate peroxidase was observed concurrently or soon after this increase in ethylene production and respiration. The increased activity of these enzymes near the peaks of ethylene production and respiration is related to the production of oxidants accompanying the onset of ripening. On the fourth day of storage, there was an increased lipid peroxidation and decreased activities of catalase, glutathione reductase and superoxide dismutase. Lipid peroxidation induces the increase of antioxidant enzymes, which can be verified by further increases in the activities of catalase, glutathione reductase, superoxide dismutase and ascorbate peroxidase. Unlike the other antioxidant enzymes, the ascorbate peroxidase activity in the pulp increased continuously during ripening, suggesting its important role in combating reactive oxygen species during papaya ripening. With regard to physical-chemical characteristics, the soluble solids did not vary significantly, the acidity and ascorbic acid contents increased, and hue angle and firmness decreased during storage. The results revealed that there was variation in the activity of antioxidant enzymes, with peaks of lipid peroxidation during the ripening of 'Golden' papaya. These results provide a basis for future research, especially with regard to the relationships among the climacteric stage, the activation of antioxidant enzymes and the role of ascorbate peroxidase in papaya ripening.

Proteomic analysis of banana fruit reveals proteins that are differentially accumulated during ripening

Bananas (Musa spp.) are highly perishable fruit of notable economic and nutritional relevance. Because the identification of proteins involved in metabolic pathways could help to extend green-life and improve the quality of the fruit, this study aimed to compare the proteins of banana pulp at the pre-climacteric and climacteric stages. The use of two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) revealed 50 differentially expressed proteins, and comparing those proteins to the Mass Spectrometry Protein Sequence Database (MSDB) identified 26 known proteins. Chitinases were the most abundant types of proteins in unripe bananas, and two isoforms in the ripe fruit have been implicated in the stress/defense response. In this regard, three heat shock proteins and isoflavone reductase were also abundant at the climacteric stage. Concerning fruit quality, pectate lyase, malate dehydrogenase, and starch phosphorylase accumulated during ripening. In addition to the ethylene formation enzyme amino cyclo carboxylic acid oxidase, the accumulation of S-adenosyl-L-homocysteine hydrolase was needed because of the increased ethylene synthesis and DNA methylation that occurred in ripening bananas. Differential analysis provided information on the ripening-associated changes that occurred in proteins involved in banana flavor, texture, defense, synthesis of ethylene, regulation of expression, and protein folding, and this analysis validated previous data on the transcripts during ripening. In this regard, the differential proteomics of fruit pulp enlarged our understanding of the process of banana ripening. (C) 2012 Elsevier B.V. All rights reserved.

Analysis of ripening-related gene expression in papaya using an Arabidopsis-based microarray

Abstract Background Papaya (Carica papaya L.) is a commercially important crop that produces climacteric fruits with a soft and sweet pulp that contain a wide range of health promoting phytochemicals. Despite its importance, little is known about transcriptional modifications during papaya fruit ripening and their control. In this study we report the analysis of ripe papaya transcriptome by using a cross-species (XSpecies) microarray technique based on the phylogenetic proximity between papaya and Arabidopsis thaliana. Results Papaya transcriptome analyses resulted in the identification of 414 ripening-related genes with some having their expression validated by qPCR. The transcription profile was compared with that from ripening tomato and grape. There were many similarities between papaya and tomato especially with respect to the expression of genes encoding proteins involved in primary metabolism, regulation of transcription, biotic and abiotic stress and cell wall metabolism. XSpecies microarray data indicated that transcription factors (TFs) of the MADS-box, NAC and AP2/ERF gene families were involved in the control of papaya ripening and revealed that cell wall-related gene expression in papaya had similarities to the expression profiles seen in Arabidopsis during hypocotyl development. Conclusion The cross-species array experiment identified a ripening-related set of genes in papaya allowing the comparison of transcription control between papaya and other fruit bearing taxa during the ripening process.

Proteomic Analysis of Chloroplast-to-Chromoplast Transition in Tomato Reveals Metabolic Shifts Coupled with Disrupted Thylakoid Biogenesis Machinery and Elevated Energy-Production Components

A comparative proteomic approach was performed to identify differentially expressed proteins in plastids at three stages of tomato (Solanum lycopersicum) fruit ripening (mature-green, breaker, red). Stringent curation and processing of the data from three independent replicates identified 1,932 proteins among which 1,529 were quantified by spectral counting. The quantification procedures have been subsequently validated by immunoblot analysis of six proteins representative of distinct metabolic or regulatory pathways. Among the main features of the chloroplast-to-chromoplast transition revealed by the study, chromoplastogenesis appears to be associated with major metabolic shifts: (1) strong decrease in abundance of proteins of light reactions (photosynthesis, Calvin cycle, photorespiration) and carbohydrate metabolism (starch synthesis/degradation), mostly between breaker and red stages and (2) increase in terpenoid biosynthesis (including carotenoids) and stress-response proteins (ascorbate-glutathione cycle, abiotic stress, redox, heat shock). These metabolic shifts are preceded by the accumulation of plastid-encoded acetyl Coenzyme A carboxylase D proteins accounting for the generation of a storage matrix that will accumulate carotenoids. Of particular note is the high abundance of proteins involved in providing energy and in metabolites import. Structural differentiation of the chromoplast is characterized by a sharp and continuous decrease of thylakoid proteins whereas envelope and stroma proteins remain remarkably stable. This is coincident with the disruption of the machinery for thylakoids and photosystem biogenesis (vesicular trafficking, provision of material for thylakoid biosynthesis, photosystems assembly) and the loss of the plastid division machinery. Altogether, the data provide new insights on the chromoplast differentiation process while enriching our knowledge of the plant plastid proteome.

2D-DIGE analysis of mango (Mangifera indica L.) fruit reveals major proteomic changes associated with ripening

A comparative proteomic investigation between the pre-climacteric and climacteric mango fruits (cv. Keitt) was performed to identify protein species with variable abundance during ripening. Proteins were phenol-extracted from fruits, cyanine-dye-labeled, and separated on 2D gels at pH 4-7. Total spot count of about 373 proteins spots was detected in each gel and forty-seven were consistently different between pre-climacteric and climacteric fruits and were subjected to LC-MS/MS analysis. Functional classification revealed that protein species involved in carbon fixation and hormone biosynthesis decreased during ripening, whereas those related to catabolism and the stress-response, including oxidative stress and abiotic and pathogen defense factors, accumulated. In relation to fruit quality, protein species putatively involved in color development and pulp softening were also identified. This study on mango proteomics provides an overview of the biological processes that occur during ripening. (C) 2012 Elsevier B.V. All rights reserved.

Influence of different banana cultivars on volatile compounds during ripening in cold storage

The aroma responsible for the flavor of fruits is highly susceptible to low temperatures in storage. The present study investigated the volatile composition of the Nanicao and Prata banana cultivars by testing pulp and whole fruit under cold storage conditions. The volatile fractions were characterized using headspace solid phase micro-extraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). The cold storage induced changes in the volatile profile relative to the profile of the control group. The result of principal component analysis revealed that cold storage more strongly affects the Nanicao than the Prata cultivar. Esters such as 2-pentanol acetate, 3-methyl-1-butanol acetate, 2-methylpropyl butanoate, 3-methylbutyl butanoate, 2-methylpropyl 3-methylbutanoate and butyl butanoate were drastically reduced in the cold group of the Nanicao cultivar. Our results suggest that the metabolism responsible for the production of volatile compounds is related to the ability to tolerate low temperatures. (C) 2012 Elsevier Ltd. All rights reserved.

Gene expression profile during coffee fruit development and identification of candidate markers for phenological stages

The objective of this work was to identify genes that could be used as suitable markers for molecular recognition of phenological stages during coffee (Coffea arabica) fruit development. Four cultivars were evaluated as to their differential expression of genes associated to fruit development and maturation processes. Gene expression was characterized by both semi-quantitative and quantitative RT-PCR, in fruit harvested at seven different developmental stages, during three different seasons. No size polymorphisms or differential expression were observed among the cultivars for the evaluated genes; however, distinct expression profiles along fruit development were determined for each gene. Four out of the 28 evaluated genes exhibited a regular expression profile in all cultivars and harvest seasons, and, therefore, they were validated as candidate phenological markers of coffee fruit. The gene a-galactosidase can be used as a marker of green stage, caffeine synthase as a marker of transition to green and yellowish-green stages, and isocitrate lyase and ethylene receptor 3 as markers of late maturation.

Effects of Black Leaf Streak Disease and Sigatoka Disease on fruit quality and maturation process of bananas produced in the subtropical conditions of southern Brazil

Banana fruits are harvested at the green-mature stage (pre-climacteric) in order to allow sufficient time for transport and marketing. The time between the harvest and the initiation of the natural ripening process is called green life (GL), which is closely correlated to physiological age. Sigatoka Disease (SD: also called yellow Sigatoka) and Black Leaf Streak Disease (BLSD; also called black Sigatoka) are the main foliar diseases affecting banana production. The aim of this work was to investigate the influence of these diseases on banana GL and postharvest behavior in subtropical conditions (southeastern Brazil). The results showed that both diseases shortened the banana's GL when compared to control bananas of the same physiological age. Moreover, fruits from infested plots showed higher values of CO2 (+100% for SD and +300% for BLSD) and C2H4 production (+30% for SD and +60% for BLSD) at the climacteric peak. BLSD caused 40% reduction in fruit weight. Fruits from plants with a high degree of SD or BLSD undergo an altered maturation process. (C) 2011 Elsevier Ltd. All rights reserved.

PHENOLOGY AND FRUIT TRAITS OF ARCHONTOPHOENIX CUNNINGHAMIANA, AN INVASIVE PALM TREE IN THE ATLANTIC FOREST OF BRAZIL

The Australian palm Archontophoenix cunninghamiana was introduced into Brazil as an ornamental species, and became a dangerous invader of remnant Atlantic forest patches, demanding urgent management actions that require careful planning. Its fruits are greatly appreciated by generalist birds and its sudden eradication could be as harmful as its permanence in the native community. Our hypothesis was that A. cunninghamiana phenology and fruit traits would have facilitated the invasion process. Hence the aim of the study was to characterize the reproductive phenology of the palm by registering flowering and fruiting events, estimating fruit production, and evaluating fruit nutritional levels. Phenological observations were carried out over 12 months and analyzed statistically. Fruit traits and production were estimated. Pulp nutritional levels were determined by analyzing proteins, lipids, and carbohydrates. Results showed constant flowering and fruiting throughout the year with a weak reproductive seasonality. On average, 3651 fruits were produced per bunch mainly in the summer. Fruit analysis revealed low nutrient contents, especially of proteins and lipids compared with other Brazilian native palm species. We concluded that the abundant fruit production all year round, and fruit attractivity mainly due to size and color, :may act positively on the reproductive performance and effective dispersion of A. cunninghamiana. As a management procedure which would add quality to frugivore food resources we suggest the replacement of A. cunninghamiana by the native palm Euterpe edulis, especially in gardens and parks near to Atlantic forest fragments.

The importance of plant diversity in maintaining the pollinator bee, Eulaema nigrita (Hymenoptera: Apidae) in sweet passion fruit fields

The euglossine bee Eulaema nigrita plays an important role for the pollination of native and economically important plants, such as the sweet passion-fruit Passiflora alata. E. nigrita uniquely collects the nectar from the flowers of P alata, nevertheless, it needs to visit other plants to collect pollen, nectar and other resources for its survival. There are two methods to identify the species of plants used by bees in their diet: by direct observation of the bees in the flowers, and through identification of pollen grains present in brood cells, feces, or in the bees' body. In order to identify the other plants that E. nigrita visits, we analyzed samples of pollen grains removed from the bee's body in the course of the flowering period of P alata. Among our results, the flora visited by E. nigrita comprised 40 species from 32 genera and 19 families, some of them used as a pollen source or just nectar. In spite of being a polyletic species, E. nigrita exhibited preference for some plant species with poricidal anthers. P alata which has high sugar concentration nectar was the main source of nectar for this bee in the studied area. Nonetheless, the pollinic analysis indicated that others nectariferous plant species are necessary to keep the populations of E. nigrita. Studies such as this one are important since they indicate supplementary pollen-nectar sources which must be used for the conservation of the populations of E. nigrita in crops neighbouring areas. In the absence of pollinators, growers are forced to pay for hand pollination, which increases production costs; keeping pollinators in cultivated areas is still more feasible to ensure sweet passion fruit production. Rev. Biol. Trop. 60 (4): 1553-1565. Epub 2012 December 01.

CHARACTERIZATION STUDY OF CAMBUCI FRUIT [Campomanesia phaea (O. Berg.) Landrum] AND ITS APPLICATION IN JELLY PROCESSING

CHARACTERIZATION STUDY OF CAMBUCI FRUIT [Campomanesia phaea (O. Berg.) Landrum] AND ITS APPLICATION IN JELLY PROCESSING The objective of this paper was to study possible differences of varieties of cambuci fruit reported by producers by means of fruit characterization and elaboration of jelly. The fruits were divided in four possible varieties groups, named as A, B, C and D, and submitted to analysis regarding weight, ash, moisture, pH, soluble solids, acidity, ratio, ascorbic acid and water activity. To the preparation of the jelly was chosen the variety A with two formulations, 50%50% and 40%60%, fruit and sugar respectively. Concerning the possible varieties of cambuci only water activity was not significantly different. The acidity and ratio of B variety are noteworthy, because it did differ from the others presenting a more satisfactory result for in natura consumption. All other tests presented statistic alteration of at least one variety, but since these data can be influenced by edaphoclimatic conditions they must be carefully observed. Lower results for pH, acidity, luminosity and degrees hue, were observed for the 60% sugar jelly sample, which contributed for its better results in the preference test for the attributes appearance, color, flavor and texture. The evaluation of attribute aroma of both samples (50% and 60%) did not differ.

Bioactive compounds and phenolic-linked functionality of powdered tropical fruit residues

Tropical fruit residues consisting of seeds, peels and residual pulp generated as by-products of fruit processing industry were investigated for bioactive compounds, the in vitro antioxidant capacity as well as alpha-glucosidase and alpha-amylase inhibitory activities. Cyanidin, quercetin, ellagic acid (EA) and proanthocyanidins were found in acerola, jambolan, pitanga and caja-umbu residue powders. Acerola powder had the highest phenolic content (8839.33 mg catechin equivalents (CE)/100 g) and also high-ascorbic acid (AA) concentration (2748.03 mg/100 g), followed by jambolan and pitanga. The greatest 1,1-Diphenyl-2-picrylhydrazyl (DPPH) inhibition was observed for jambolan (436.76 mmol Trolox eq/g) followed by pitanga (206.68 mmol Trolox eq/g) and acerola (192.60 mmol Trolox eq/g), while acerola had the highest ferric reducing antioxidant power (FRAP) assay result (7.87 mmol Trolox eq/g). All fruit powders exhibited enzymatic inhibition against alpha-amylase (IC50 ranging from 3.40 to 49.5 mg CE/mL) and alpha-glucosidase (IC50 ranging from 1.15 to 2.37 mg CE/mL). Therefore, acerola, jambolan and pitanga dried residues are promising natural ingredients for food and nutraceutical manufacturers, due to their rich bioactive compound content.

Characterization of the procera Tomato Mutant Shows Novel Functions of the SlDELLA Protein in the Control of Flower Morphology, Cell Division and Expansion, and the Auxin-Signaling Pathway during Fruit-Set and Development

procera (pro) is a tall tomato (Solanum lycopersicum) mutant carrying a point mutation in the GRAS region of the gene encoding SlDELLA, a repressor in the gibberellin (GA) signaling pathway. Consistent with the SlDELLA loss of function, pro plants display a GA-constitutive response phenotype, mimicking wild-type plants treated with GA(3). The ovaries from both nonemasculated and emasculated pro flowers had very strong parthenocarpic capacity, associated with enhanced growth of preanthesis ovaries due to more and larger cells. pro parthenocarpy is facultative because seeded fruits were obtained by manual pollination. Most pro pistils had exserted stigmas, thus preventing self-pollination, similar to wild-type pistils treated with GA(3) or auxins. However, Style2.1, a gene responsible for long styles in noncultivated tomato, may not control the enhanced style elongation of pro pistils, because its expression was not higher in pro styles and did not increase upon GA(3) application. Interestingly, a high percentage of pro flowers had meristic alterations, with one additional petal, sepal, stamen, and carpel at each of the four whorls, respectively, thus unveiling a role of SlDELLA in flower organ development. Microarray analysis showed significant changes in the transcriptome of preanthesis pro ovaries compared with the wild type, indicating that the molecular mechanism underlying the parthenocarpic capacity of pro is complex and that it is mainly associated with changes in the expression of genes involved in GA and auxin pathways. Interestingly, it was found that GA activity modulates the expression of cell division and expansion genes and an auxin signaling gene (tomato AUXIN RESPONSE FACTOR7) during fruit-set.

Effect of quarantine treatments on the carbohydrate and organic acid content of mangoes (cv. Tommy Atkins)

Brazil is one of the largest mango producers and the third largest mango exporter worldwide. Irradiation treatment and its commercial feasibility have been studied in our country to make it possible to develop new markets and, consequently, to compete with the major exporters of mangoes, Mexico and India. This work was designed to compare irradiation treatment with the hot water dip treatment in mangoes cv. Tommy Atkins for export and to verify that the main attributes for acceptance, color and texture, as well as carbohydrate and organic acid contents, were maintained. In this study, the fruit was divided into groups: control, hot water dip-treated (46 degrees C for 90 min), and irradiation-treated at doses of 0.4 kGy and 1.0 kGy. The fruit was stored at low temperature (11 degrees C +/- 2) for 14 days and then at room temperature (23 degrees C +/- 2) until the end of the study. The results indicated that the fruit given a dose of 1.0 kGy remained in a less advanced stage of ripening (stage 3) throughout the storage period, but experienced a greater loss of texture in the beginning of the experiment. It was noted that only the control group had higher levels of citric acid and succinic acid on the last day of the experiment. There were no significant differences in the total sugar content between any treatment groups. Gamma radiation can be used as a quarantine treatment and does not interfere negatively with the quality attributes of mangoes. (C) 2012 Elsevier Ltd. All rights reserved.