Mature Green Stage Research Articles

Suppression of volatile production in tomato fruit exposed to chilling temperature and alleviation of chilling injury by a pre-chilling heat treatment

Chilling exposure of tomato fruit to 5 °C for less than 5 days at mature green stage does not cause visual symptom of chilling injury (CI), however, it is unknown whether such conditions would impact flavour quality (internal CI) after ripening, and if a pre-chilling heat treatment could alleviate internal CI. In this experiment, mature green ‘FL 47’ tomatoes were gassed with ethylene to initiate ripening before heating and/or chilling treatment, and fruits were ripened at 20 °C after short exposure to the high or low temperature. Volatile analysis of the fruits were conducted after ripening. Chilling treatment generally suppressed production of aldehyde, alcohol, ketone, ester, acid and terpene volatile compounds, including the following abundant and/or important volatiles: hexanal, trans-2-hexenal, 6-methyl-5-hepten-2-one, β-ionone, 2-methylbutanal, 2-phenylethanol, guaiacol and 2-isobutylthiazole. Heat treatment alone did not affect most volatile levels after ripening. Heat treatment prior to chilling exposure alleviated the reduction of some key volatile compounds caused by chilling exposure, which agreed with sensory panel results in that panellists perceived more tomato flavour in “heating + chilling” treated fruit than fruit that were chilled only.

Respiration rate model for mature green capsicum (Capsicum annum L.) under closed aerobic atmospheric conditions

The respiration rate of green capsicum cv. ‘Swarna’ fruits harvested at mature green stage were determined under closed system at 10, 15 and 20 oC temperatures. A simple Michaelis-Menten kinetic model coupled with Arrhenius-type equation, which describes temperature as a function of respiration rate, was used to model the respiration rate of capsicum. The respiration rate model parameters at defined temperature were estimated by fitting the model to the experimental set of data by non-linear regression analysis method. The respiration rate of green mature capsicum was influenced by the temperature. The Arrhenius equation well described the relationship between enzyme kinematics model parameters and temperature. The values of Michaelis-Menten constant for oxygen (Kmo2) and carbon dioxide (Kmco2) were found to vary from 2.14 to 3.92 and 1.33 to 3.24, respectively at different temperature. Experimental and predicted RRO2 values for mature green capsicum was found to be ranged from 9.54 to 14.54 and 11.81 to 17.52 mg/kg-h, respectively. Whereas, the experimental and predicted RRCO2 were 20.1 to 38.51 and 22.15 to 39.83 mg/ kg-h, respectively.

Resistances to anthracnose (Colletotrichum acutatum) of Capsicum mature green and ripe fruit are controlled by a major dominant cluster of QTLs on chromosome P5

Anthracnose (Colletotrichum spp.) is a serious disease worldwide in pepper (Capsicum) production. Inheritance of resistance to Colletotrichum acutatum from a Capsicum chinense accession (PBC932) was studied in a BC1 population derived from a hybrid with Capsicum annuum line 77013 (susceptible) using a QTL analysis method. Resistance test was performed on detached mature green and mature red fruit under laboratory conditions by evaluated in disease incidence, true lesion diameter and overall lesion diameter. Based on a linkage map with 14 linkage groups, 385 markers (SSR, InDel and CAPS), 1310.2cM in length, inclusive Composite Interval Mapping (ICIM) revealed main effect QTLs located in a close marker interval on P5 chromosome for all fruit stages and resistance criteria, and four minor-effect QTLs only at green mature stage. Identification of recombinant individuals suggested that resistance in green versus red fruit may be controlled by distinct genes within the QTL interval on P5.

Tomato ACS4 is necessary for timely start of and progression through the climacteric phase of fruit ripening.

Climacteric fruit ripening, as it occurs in many fruit crops, depends on a rapid, autocatalytic increase in ethylene production. This agriculturally important process has been studied extensively, with tomato simultaneously acting both as a model species and target crop for modification. In tomato, the ethylene biosynthetic genes ACC SYNTHASE2 (ACS2) and ACS4 are highly expressed during fruit ripening, with a combined loss of both ACS2 and ACS4 activity preventing generation of the ethylene burst necessary for fruit ripening. However, the individual roles and importance of ACS2 and ACS4 have not been determined. In this study, we examined specifically the role of ACS4 by comparing the phenotype of an acs4 mutant firstly with that of the wild-type, and secondly with two novel ripening-inhibitor (rin) mutants. Ethylene production during ripening was significantly reduced in both acs4-1, and rin lines, with rin genotypes showing the weaker ethylene burst. Also i) the time between anthesis and the start of fruit ripening and ii) the time required to progress through ripening were significantly longer in acs4-1 than in the wild type, but shorter than in the strongest rin mutant. The delay in ripening was reflected in the lower expression of ripening-related transcripts during the mature green and light red ripening stages. Furthermore, expression of ACS2 and ACS4 was strongly dependent on a functional RIN gene, while ACS2 expression was largely independent of ACS4. Altogether, we show that ACS4 is necessary for normal progression of tomato fruit ripening and that mutation of this gene may provide a useful means for altering ripening traits.

Study of alternative oxidase in seeded and parthenocarpic cherry tomato fruits during their development and postharvest storage

Alternative oxidase holds an enigmatic role in cellular metabolism. The effect of auxin-induced parthenocarpy of tomato fruits on the transcript accumulation of three genes, belonging to two-gene families, and on the immunolocalization of the protein of alternative oxidase were studied. The genes of the alternative oxidase 1 family were transcribed more abundantly in seeded fruits than in parthenocarpic ones during the climacteric fruit period. Moreover, there was a clearly distinctive pattern of transcript accumulation between genes of alternative oxidase 1 and alternative oxidase 2 families. Maximum accumulation of alternative oxidase gene transcripts coincided with the climacteric rise of respiration in mature green and breaker stages, whereas alternative oxidase 2-gene transcript accumulation was highest in immature green fruits. After postharvest storage of fruits close to plantation for 120 h and at 5 °C, the relative transcript accumulation of all studied genes significantly increased in both fruit types; the effect, however, on seeded and on parthenocarpic fruits was not of the same level. The immunolocalization of alternative oxidase protein revealed a strong presence of alternative oxidase in the developing seeds. In conclusion, considerable differences were found in the regulation of alternative oxidase between seeded and parthenocarpic fruits during their development and postharvest storage.

Stone Cell Frequency and Cell Area Variation of Crisp and Standard Texture Southern Highbush Blueberry Fruit

Sclerified stone cells with a thick and lignified secondary cell wall are known to vary in number among cultivars of northern highbush blueberry (Vaccinium corymbosum) and rabbiteye blueberry (Vaccinium virgatum), and may contribute to fruit texture. Variation in cell size can also contribute to differences in fruit firmness. Fruit from nine southern highbush blueberry [SHB (V. corymbosum interspecific hybrids)] cultivars determined by sensory and instrumental analysis to vary in fruit texture were harvested at mature green and ripe blue developmental stages. Paraffin embedded 12-μm sections were stained with Safranin O and Aniline Blue and microstructure was examined by light microscopy. Stone cells within ≈1.2 mm of the epidermis were counted and cell area was measured in the epidermal layer and three layers beneath the epidermis of the fruit. There was a significant difference in cell area among genotypes and cell layers for mature green fruit and among texture types, genotypes, and cell layers for ripe blue fruit. The average number of stone cells in a single berry ranged from zero to 95 among cultivars. Significant differences in the number of stone cells just below the epidermal layer did not correspond to standard or crisp fruit texture.

Calmodulin Gene Expression in Response to Mechanical Wounding and Botrytis cinerea Infection in Tomato Fruit.

Calmodulin, a ubiquitous calcium sensor, plays an important role in decoding stress-triggered intracellular calcium changes and regulates the functions of numerous target proteins involved in various plant physiological responses. To determine the functions of calmodulin in fleshy fruit, expression studies were performed on a family of six calmodulin genes (SlCaMs) in mature-green stage tomato fruit in response to mechanical injury and Botrytis cinerea infection. Both wounding and pathogen inoculation triggered expression of all those genes, with SlCaM2 being the most responsive one to both treatments. Furthermore, all calmodulin genes were upregulated by salicylic acid and methyl jasmonate, two signaling molecules involved in plant immunity. In addition to SlCaM2, SlCaM1 was highly responsive to salicylic acid and methyl jasmonate. However, SlCaM2 exhibited a more rapid and stronger response than SlCaM1. Overexpression of SlCaM2 in tomato fruit enhanced resistance to Botrytis-induced decay, whereas reducing its expression resulted in increased lesion development. These results indicate that calmodulin is a positive regulator of plant defense in fruit by activating defense pathways including salicylate- and jasmonate-signaling pathways, and SlCaM2 is the major calmodulin gene responsible for this event.

Fruit Maturity Phenolic Content and Antioxidant Activity of <i>Eugenia jambolana</i> Lam Fruit

Fruits of Eugenia jambolana were analysed for total phenolics and antioxidant activity of three successive development stages viz. 1. Mature green 2. Half - ripened and 3. Fully ripened. The total anthocyanin concentrations were higher in fully ripened stage, the total phenolic content was maximum achieved in mature green stage (354 mg L-1). Antioxidant activity also strongly depended on ripening stages, showing completely opposite compared to that of total phenolics. Since total phenolics and antioxidant activity performed nearly “Object and its reflection in the mirror” trend.

Fruit Maturity Phenolic Content and Antioxidant Activity of <i>Eugenia jambolana</i> Lam Fruit

Fruits of Eugenia jambolana were analysed for total phenolics and antioxidant activity of three successive development stages viz. 1. Mature green 2. Half - ripened and 3. Fully ripened. The total anthocyanin concentrations were higher in fully ripened stage, the total phenolic content was maximum achieved in mature green stage (354 mg L-1). Antioxidant activity also strongly depended on ripening stages, showing completely opposite compared to that of total phenolics. Since total phenolics and antioxidant activity performed nearly “Object and its reflection in the mirror” trend.

ITRAQ Protein Profile Analysis of Tomato Green-ripe Mutant Reveals New Aspects Critical for Fruit Ripening

Green-ripe (Gr) tomato carries a dominant mutation and yields a nonripening fruit phenotype. The mutation results from a 334 bp deletion in a gene of unknown function at the Gr locus. The putative influence of Gr gene-deletion mutation on biochemical changes underlying the nonripening phenotype remains largely unknown. Respiration of Gr fruit was found to be reduced at mature green and breaker stage of ripening, while the fruit softening was dramatically prolonged. We studied the proteome of Gr mutant fruit using high-throughput iTRAQ and high-resolution mass spectrometry and identified 43 proteins representing 43 individual genes as potential influence-targets of Gr mutated fruit. The identified proteins are involved in several ripening-related pathways including cell-wall metabolism, photosynthesis, oxidative phosphorylation, carbohydrate and fatty acid metabolism, protein synthesis, and processing. Affected protein levels are correlated with the corresponding gene transcript levels. The modulation in the accumulation levels of PI(U1)P, PGIP, and PG2 supported the delayed softening phenotype of the Gr fruit. Further investigation in GR gene-silencing fruit ascertained the doubtless modulation of these targets by the deletion mutation of GR gene.

Changes in ethylene signaling and MADS box gene expression are associated with banana finger drop

Banana finger drop was examined in ripening banana harvested at immature (iMG), early (eMG) and late mature green (lMG) stages, with contrasting ripening rates and ethylene sensitivities. Concomitantly, 11 ethylene signal transduction components (ESTC) and 6 MADS box gene expressions were comparatively studied in median (control zone, CZ) and pedicel rupture (drop zone DZ) areas in peel tissue. iMG fruit did not ripen or develop finger drop while eMG and lMG fruits displayed a similar finger drop pattern. Several ESTC and MADS box gene mRNAs were differentially induced in DZ and CZ and sequentially in eMG and lMG fruits. MaESR2, 3 and MaEIL1, MaMADS2 and MaMADS5 had a higher mRNA level in eMG and acted earlier, whereas MaERS1, MaCTR1, MaEIL3/AB266319, MaEIL4/AB266320 and MaEIL5/AB266321, MaMADS4 and to a lesser extent MaMADS2 and 5 acted later in lMG. In this fruit, MaERS1 and 3, MaCTR1, MaEIL3, 4 and MaEIL5/AB266321, and MaMADS4 were enhanced by finger drop, suggesting their specific involvement in this process. MaEIL1, MaMADS1 and 3, induced at comparable levels in DZ and CZ, are probably related to the overall fruit ripening process. These findings led us to consider that developmental cues are the predominant finger drop regulation factor.

Proteomics study of the effects of high pigment-1 on plastid differentiation during the ripening of tomato fruits

The chloroplast-to-chromoplast difference is a highly regulated process. Tomato (Solanum lycopersicum) high-pigment mutant hp-1 shows an enhanced accumulation of carotenoids coupled with an increase in the volume and number of plastids. However, how chromoplasts of hp-1 acquire their specific metabolic characteristics is still unclear. A comparison of proteome profiles from plastids at the mature green, breaker, and red stages of tomato fruits showed 45 differentially expressed proteins. These identified proteins fell into six different functional categories. Our results showed that most of the proteins related to the Calvin cycle increased transitorily only at the early breaker stage, and remained unchanged at the early red stage. We found 18 proteins that were differentially expressed between the wild type and hp-1. The abundance of GCPE in chromoplasts of hp-1 was higher than that in the wild type. Meanwhile, we found that heat shock proteins were only present specifically in the mature green stage chromoplasts of hp-1 but not in the wild type. This suggested that GCPE and heat shock proteins might play important roles in the accumulation of high carotenoids in hp-1. Overall, our results could be helpful for understanding chloroplast-to-chromoplast differentiation and the function of hp-1.

Effects of drought stress on capsanthin during fruit development and ripening in pepper (Capsicum annuum L.)

In recent years, soil drought has become a major bottleneck restricting the development of agriculture in the southwestern and northwestern parts of China. In these arid regions, pigment pepper cultivation has become an important local industry. The effect of drought on capsanthin production in pepper fruits has not been well studied. The aim of this work was to evaluate the effects of drought stress on capsanthin accumulation in pepper fruits, and to evaluate the effects of drought on the expression of key genes in the capsanthin biosynthetic pathway. A simple weighing method was used to adjust the pot soil water content. The water supply was controlled when fruits were at the mature-green stage on day 20 after flowering. HPLC was used to determine the fruit capsanthin content, and quantitative real-time PCR was used to quantify the expression of key genes. Cv. Yiduhong was used as a model. Our results showed that drought significantly affected capsanthin synthesis in pepper fruits; moderate to severe drought had the greatest impact on capsanthin accumulation. At the same time, we found that capsanthin levels could be restored if water was supplied to the drought-stressed plants during the stages of fruit development and ripening. Analyzing the expression of key genes in the capsanthin biosynthesis pathway indicated that drought had little effect on capsanthin/capsorubin synthase (Ccs) gene expression, but that soil drought has a greater effect on the expression of the lycopene-β-cyclase (Lcyb) and β-carotene hydroxylase (Crtz) genes, resulting in a significant reduction in the fruit capsanthin content in pepper

Effects of chlorine dioxide treatment on respiration rate and ethylene synthesis of postharvest tomato fruit

Tomato fruit at the mature green stage were treated with ClO2 gas in a sealed container for 12h, and then stored at 23°C with 85% relative humidity (RH) for 23 d. Respiration rate, respiration-related enzymes including phosphohexose isomerase (PHI), succinate dehydrogenase (SDH), and glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), ethylene production, and the expression of LeAOX1a, LeCOX1, LeACS2, LeACS4 and LeACO1 genes were measured. The results showed that application of ClO2 gas was effective in reducing total respiration, cytochrome pathway respiration and the expression of LeCOX1, but no significant reduction in the activities of respiration-related enzymes was observed during storage. Fruit treated with ClO2 resulted in lower ethylene production. Furthermore, the expression of ethylene biosynthesis related genes, including LeACS2, LeACS4 and LeACO1 was reduced by the ClO2 treatment. These results indicate that ClO2 treatment might delay the ripening of tomato fruit, possibly by a mechanism involving suppression of respiration rate and ethylene biosynthesis.

Mango trees have no distinct phenology: The case of mangoes in the tropics

We propose a convenient, easily observable set of landmark developmental stages during vegetative and flowering flushes and fruiting events to characterize the changes through which individual growing mango shoots pass in the tropics and subtropics. Individual non-growing stems are in the Resting stage (R), when the apical bud (following a previous vegetative growth event) or lateral buds (following a previous flowering event) are dormant. A flush event is one in which the resting buds on many stems in a section of tree canopy initiate growth (asynchronous flush) or when the entire canopy initiates bud growth at once (synchronous flush). The stages describing vegetative shoot growth are: Vegetative Bud Emergence and Development stage, Elongating Green Leaf stage, Limp Red Leaf stage (LRL), Immature Green Leaf stage, and Mature Green Leaf stage. Reproductive growth stages in purely flowering, or generative, shoots are: Floral Bud Initiation, Emergence and Development stage, Early Panicle Elongation stage, Mid-size Panicle Early Anthesis stage, and Full-size Panicle Maximum Anthesis stage. Fruiting stages are: Emergent Fruit stage, Small-size Green Fruit stage, Mid-size Green Fruit stage, Near Full-size Immature Fruit stage, and the Full-size Mature Fruit stage. Mixed shoots, bearing both leaves and lateral inflorescences at each node, exhibit characteristics of both vegetative and flowering shoots. Landmark stages for Tommy Atkins and Keitt, two cultivars commercially growing in the Americas, were observed in tropical orchards near the village of La Mesa, Colombia. Tommy Atkins leaves had a more intense red coloration during the LRL than did ‘Keitt’. More pedicels were found in ‘Tommy Atkins’ than in ‘Keitt’ during panicle development. Young fruits of ‘Tommy Atkins’ developed their distinctive, dark red coloration, whereas ‘Keitt’ fruit developed less intense reddish coloration once they were mature. Aside from these minor phenotypic differences in distinctive shoot and stem developmental stages, attempts to ascribe a distinct phenological pattern of mango tree growth and development are impractical. Each stem terminal or groups of stem terminals borne on scaffolding branches act as independent structures influenced by environmental conditions, such as temperature, water relations, and nutrition coupled with their physiological age resulting in widely variable tree responses even in similar environments.

Impact of postharvest nitric oxide treatment on antioxidant enzymes and related genes in banana fruit in response to chilling tolerance

Banana fruits harvested at the mature green stage were treated with 60μLL−1 nitric oxide (NO) for 3h at 22°C, and then stored at 7±1°C with 90% RH for 15 days. The results showed that the application of NO at 60μLL−1 was most effective in reducing chilling injury in banana fruit. The treatment reduced increases in electrolyte leakage and malondialdehyde content, and delayed increases in both superoxide anion (O2−) production rate and H2O2 content. Fruit treated with NO exhibited higher activities of superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and ascorbate peroxidase (APX), and significantly higher expression of MaSOD, MaCAT, MaPOD and MaAPX genes than control fruit during storage. These results indicate that NO treatment might enhance chilling tolerance of banana fruit via improving the activities of antioxidant enzymes and inducing the expression of antioxidant-related genes.

A Comparative Study of Lectin Affinity Based Plant N-Glycoproteome Profiling Using Tomato Fruit as a Model

Lectin affinity chromatography (LAC) can provide a valuable front-end enrichment strategy for the study of N-glycoproteins and has been used to characterize a broad range eukaryotic N-glycoproteomes. Moreover, studies with mammalian systems have suggested that the use of multiple lectins with different affinities can be particularly effective. A multi-lectin approach has also been reported to provide a significant benefit for the analysis of plant N-glycoproteins; however, it has yet to be determined whether certain lectins, or combinations of lectins are optimal for plant N-glycoproteome profiling; or whether specific lectins show preferential association with particular N-glycosylation sites or N-glycan structures. We describe here a comparative study of three mannose-binding lectins, concanavalin A, snowdrop lectin, and lentil lectin, to profile the N-glycoproteome of mature green stage tomato (Solanum lycopersicum) fruit pericarp. Through coupling lectin affinity chromatography with a shotgun proteomics strategy, we identified 448 putative N-glycoproteins, whereas a parallel lectin affinity chromatography plus hydrophilic interaction chromatography analysis revealed 318 putative N-glycosylation sites on 230 N-glycoproteins, of which 100 overlapped with the shotgun analysis, as well as 17 N-glycan structures. The use of multiple lectins substantially increased N-glycoproteome coverage and although there were no discernible differences in the structures of N-glycans, or the charge, isoelectric point (pI) or hydrophobicity of the glycopeptides that differentially bound to each lectin, differences were observed in the amino acid frequency at the -1 and +1 subsites of the N-glycosylation sites. We also demonstrated an alternative and complementary in planta recombinant expression strategy, followed by affinity MS analysis, to identify the putative N-glycan structures of glycoproteins whose abundance is too low to be readily determined by a shotgun approach, and/or combined with deglycosylation for predicted deamidated sites, using a xyloglucan-specific endoglucanase inhibitor protein as an example.

Effect of Gamma Radiation on Tomato Quality during Storage and Processing

Fruits of two tomato cultivars Amani and Beto86 were exposed to gamma rays doses of 0.25, 0.50 and 1.00 KGy at mature green stage during 2010\2011 season to delay their ripening period and hence extend their shelf life. Tomato fruits were stored at 15±1°C (85-90% R.H) and examined for physiological and physicochemical changes during storage period. Organoleptic qualities were made for Beto86 tomato paste and fresh slices prepared from Amani tomato cultivar. Irradiation treatments doubled the shelf life of tomato fruits in both cultivars. Gamma radiation treatment at all doses has decreased significantly (p≤0.05) the weight loss, respiration rate and delay the softening of tomato fruits in both cultivars. The maximum level of ascorbic acid, total soluble solids and total sugars was reached in more time with irradiated fruits compared to untreated fruits. No significant difference was observed in tomato paste made from Beto 86 and fresh tomato slices prepared from Amani fruits among the treated fruits in terms of color, texture, taste and flavor and over all acceptability.

Pericarp polypeptides and SRAP markers associated with fruit quality traits in an interspecific tomato backcross

The aim of this study was to detect polypeptides and genomic regions associated with fruit quality traits in a backcross generation using as parent the Argentinean cultivated tomato Caimanta of Solanum lycopersicum and the wild accession LA722 of S. pimpinellifolium. We tested two types of molecular marker: polypeptide profile (at two ripening stages, mature green and red ripe) and SRAP (sequence-related amplified polymorphism). A polypeptide of 45 kDa present in the wild parents at the mature green stage was associated with larger fruit and long shelf life. Some amplification fragments from SRAP markers were associated with more than one quality trait such as fruit color, firmness, titratable acidity, and fruit soluble solids content. This study demonstrated for the first time the usefulness of the polypeptide profiles of pericarp and SRAP markers in finding associations with quality fruit traits in a tomato backcross generation.

Effect of Modified Atmosphere Packaging on Storage of Baramasi lemon (Citrus limon(L.) Burm)

The harvesting period of winter crop of Baramasi lemon coincides with the cooler part of the year and there is often a glut like situation in the market at its peak harvest time. This results in low returns to the growers. A study was planned to enhance the storage life of baramasi lemon fruits and fruits were harvested at green mature stage along with small pedicel in the month of January. Only healthy fruits were dipped in 0.1% bavistin solution for 2 minutes and after shade drying fruits were packed (four fruits in each pack) in high density polyethylene (HDPE) and low density polyethylene (LDPE) bags. Fruits were also waxed with Citrashine wax in one treatment. Packed/treated fruits were packed in corrugated fibre board (CFB) boxes and kept at ambient conditions. Fruit samples were analysed after 20, 35 and 50 days of storage for various physico-chemical characteristics. Results revealed that fruits treated with bavistin @ 0.1% and packed in LDPE bags maintained the best fruit quality in terms of high sensory quality, juice content, acidity and low spoilage and physiological loss in weight during 50 days of ambient storage.