Mature Green Fruit Research Articles

Preserving functional properties and inhibiting postharvest peel browning in guava during cold storage via 24-epibrassinolide application

Postharvest peel browning is one of the primary issues accountable for the subdued consumer acceptability and market value of guava fruit. However, postharvest treatment with brassinosteroid can reduce the peel browning to some extent through various modes of action. In current study, the influence of exogenous 24-epibrassinolide (EBL) application on antioxidant system and chilling injury (CI) characteristics of guavas during cold storage at 10 ± 1 ℃ were assessed. The mature green fruit exposed to various concentrations (15, 30, 45, 60 and 75 µg kg−1) of EBL displayed a notably lower fruit weight loss, respiration rate, electrolyte leakage and CI index, while higher consumer acceptability. Further, treatment with EBL has recorded lower amassing of hydrogen peroxide and malondialdehyde by suppressing lipoxygenase activity. Postharvest EBL application also heightened the content of total phenolics, ascorbic acid, total flavonoids and total antioxidant capacity. The enhanced activities of ascorbate peroxidase, catalase, superoxide dismutase and peroxidase due to EBL application impede the burst of reactive oxygen species. Moreover, correlation and regression analysis of tested biochemical parameters including enzymatic and non-enzymatic antioxidants exhibited a strong association and contributed 98.24–99.88 % variability in fruit weight loss, respiration rate, electrolyte leakage, CI index and consumer acceptability. Among different concentrations tested, 60 µg kg−1 EBL-treated guavas exhibited the desirable qualities and least CI index. From the study, it is concluded that the novelty of EBL can be gainfully harnessed in a postharvest handling system to induce cold tolerance and widen the storage life of cold-stored guava fruit.

General evaluation of the distribution and commercialization cycle of bananas at the main fairs in Boa Vista - RR

In Roraima, banana cultivation is a significant socio-economic activity aimed at catering to both the domestic and regional markets. The banana-producing region (Musa spp) is concentrated in the southern part of the state, encompassing the municipalities of Caroebe, São João da Baliza, and Rorainópolis. Thus, the objective was to assess fruit damage and investigate severity and causes. The cultivars selected for the study were ‘Pacovan’, ‘Prata’, and ‘Missouri’. Five markets were visited for the study, with eleven points of sale sampled at each market. At each sampling point, newly arrived batche (bunches) was collected at three distinct times. The variable studied was the incidence of fruit damage at different ripening stages (type 2 and type 7). Data collected visually were subjected to Likert analysis and descriptive statistics. The results showed that mature bananas exposed directly on tarpaulin exhibited severe mechanical damage, such as abrasions and cuts due to direct contact with the rough surface of the tarpaulin and stacking during transport. Mature fruits transported in cardboard boxes had a lower incidence of damage and also served as a display for marketing. Mature green fruits were also affected during transport, with greater impact when in plastic bags or plastic boxes due to irregular and pointed surfaces. In the case of green-mature fruit, the damage incurred was less severe compared to mature fruit.

Application of ethanol alleviates heat damage to leaf growth and yield in tomato.

Chemical priming has emerged as a promising area in agricultural research. Our previous studies have demonstrated that pretreatment with a low concentration of ethanol enhances abiotic stress tolerance in Arabidopsis and cassava. Here, we show that ethanol treatment induces heat stress tolerance in tomato (Solanum lycopersicon L.) plants. Seedlings of the tomato cultivar 'Micro-Tom' were pretreated with ethanol solution and then subjected to heat stress. The survival rates of the ethanol-pretreated plants were significantly higher than those of the water-treated control plants. Similarly, the fruit numbers of the ethanol-pretreated plants were greater than those of the water-treated ones. Transcriptome analysis identified sets of genes that were differentially expressed in shoots and roots of seedlings and in mature green fruits of ethanol-pretreated plants compared with those in water-treated plants. Gene ontology analysis using these genes showed that stress-related gene ontology terms were found in the set of ethanol-induced genes. Metabolome analysis revealed that the contents of a wide range of metabolites differed between water- and ethanol-treated samples. They included sugars such as trehalose, sucrose, glucose, and fructose. From our results, we speculate that ethanol-induced heat stress tolerance in tomato is mainly the result of increased expression of stress-related genes encoding late embryogenesis abundant (LEA) proteins, reactive oxygen species (ROS) elimination enzymes, and activated gluconeogenesis. Our results will be useful for establishing ethanol-based chemical priming technology to reduce heat stress damage in crops, especially in Solanaceae.

Sustainable Approaches to Prolonging Shelf Life in Green Mature Tomato Fruit

Green mature tomato fruits demonstrate better transportability compared to fully matured ones. This approach has the potential to play a significant role in diminishing postharvest losses and enhancing the accessibility of nutritionally rich fruit in developing countries. The instability of electricity and insufficient cold storage facilities is recognized for fading the shelf life of various fruits and vegetables. However, post-harvest interventions, including tomatoes, can extend perishable products' shelf life. Firstly, tomato fruits were harvested at the green mature stage and stored at 33℃ for 0, 10, 20, and 30 days, followed by a shift to 25℃. Subsequently, ten fruits were subjected to various treatments: A - control (25℃), B - 33℃ with 30-40% RH, C - 33℃ with 50-60% RH, and D - 33℃ with 80-90% RH. Different relative humidity (RH) levels were achieved using saturated salts, specifically MgCl2.6H2O, Mg (NO3)2.6H2O, and KCl+KNO3 for treatments B, C, and D, respectively. The evaluation encompassed parameters such as ethylene production, CO2 release, fruit firmness, weight loss, and color development. A higher temperature, such as 33℃, may be considered advantageous for the storage of green mature tomato fruit. Evidently, tomatoes were successfully stored for over 55 days at this temperature. Across all relative humidity (RH) conditions, there was more noticeable color development in fruits stored at 25°C compared to those stored at 33°C. Among the various RH conditions, fruits stored at 33°C with 80-90% RH experienced the least weight loss, although fruit firmness gradually declined over time. Storing green mature tomato fruit at 33°C with 30-40% RH resulted in the lowest ethylene production compared to 25°C and other RH conditions. Consequently, certain practical benefits of green mature tomato fruit under elevated temperatures and diverse relative humidity (RH) conditions are suggested. However, further detailed research may be necessary to explore potential metabolic changes.

Development of Pulverized Balimbing (Averrhoa Carambola) Fruit: A Potential Food Enhancer

The balimbing (Averrhoa carambola) fruit is known for its unique star shape and reach in golden color. The fruit varies widely in its composition during maturation. Hence, this study aimed to develop a pulverized Balimbing (A. carambola) as a potent food enhancer. This study also determined the level of sourness of a pulverized A. carambola fruit sour spice at different maturity levels (unripe and ripe). Phytochemical screening was done in the Balimbing (A. carambola) fruit to determine its chemical components, secondary metabolites, and toxicity. The study utilized a descriptive research method. This design was deemed appropriate because in this study, the researcher could set up an experiment to determine the level of pH value of the pulverized A. carambola at different maturity levels, ripe and unripe. The experiment was conducted to determine the quantitative and qualitative characteristics of the pulverized Balimbing. The set-up consisted of two maturity levels: unripe and ripe. Each maturity level has three replicates. Each replicate contains a mass of 20 grams. All the replicates were evaluated for their quantitative characteristics, such as pH level. Findings revealed that A. carambola fruit differs in its pH concerning its maturity levels, with an average pH in mature green fruit (unripe) and ripe A. carambola fruit, respectively. It was found that the developed A. carambola food enhancer showed a very acceptable result in terms of texture, appearance, and flavor/taste. At the same time, its aroma was described as acceptable. Further, the moisture, strip, and pH of A. carambola show significant differences with respect to its maturity levels (ripe and unripe) at 0.01 significance level.

The influence of Morinda citrifolia fruit maturity level, parts and storage length on total phenols, ascorbic acid, antioxidant activity and ethylene gas emission

Different parts of noni plant (Morinda citrifolia) were analyzed for total phenols, total ascorbic acid and antioxidant activity at three different maturities. Results showed higher total phenols content (TPC) in seeds (9.63–12.48) than in pulp (4.47–8.69), and leaves (3.55–6.51 mg GAE/g−1 DW). Ascorbic acid content ranged between 0.21–0.90, 0.23–0.97 and 0.30–0.69 mg g−1 for pulp, skin and leaves respectively. Immature fruits had higher TPC and higher antioxidant activity than mature ripe fruits and leaves. Total ascorbic acid content was highest (P < 0.05) in the seeds (1.31–1.79 mg g−1). Mature ripe fruits should be harvested for high ascorbic acid contents. For functional benefits and medicinal use, mature green fruits are recommended for the best antioxidant potential and phenol content. Longer storage resulted in higher ethylene biosynthesis which correlated inversely to total phenols content (-0.92) and antioxidant activity (-0.92). Further compositional and in vivo analyses of noni plant parts is suggested.

An evolutionary view of vanillylamine synthase pAMT, a key enzyme of capsaicinoid biosynthesis pathway in chili pepper.

Pungent capsaicinoid is synthesized only in chili pepper (Capsicum spp.). The production of vanillylamine from vanillin is a unique reaction in the capsaicinoid biosynthesis pathway. Although putative aminotransferase (pAMT) has been isolated as the vanillylamine synthase gene, it is unclear how Capsicum acquired pAMT. Here, we present a phylogenetic overview of pAMT and its homologs. The Capsicum genome contained 5 homologs, including pAMT, CaGABA-T1, CaGABA-T3, and two pseudogenes. Phylogenetic analysis indicated that pAMT is a member of the Solanaceae cytoplasmic GABA-Ts. Comparative genome analysis found that multiple copies of GABA-T exist in a specific Solanaceae genomic region, and the cytoplasmic GABA-Ts other than pAMT are located in the region. The cytoplasmic GABA-T was phylogenetically close to pseudo-GABA-T harboring a plastid transit peptide (pseudo-GABA-T3). This suggested that Solanaceae cytoplasmic GABA-Ts occurred via duplication of a chloroplastic GABA-T ancestor and subsequent loss of the plastid transit signal. The cytoplasmic GABA-T may have been translocated from the specific Solanaceae genomic region during Capsicum divergence, resulting in the current pAMT locus. A recombinant protein assay demonstrated that pAMT had higher vanillylamine synthase activity than those of other plant GABA-Ts. pAMT was expressed exclusively in the placental septum of mature green fruit, whereas tomato orthologs SlGABA-T2/4 exhibit a ubiquitous expression pattern in plants. These findings suggested that both the increased catalytic efficiency and transcriptional changes in pAMT may have contributed to establish vanillylamine synthesis in the capsaicinoid biosynthesis pathway. This study provides insights into the establishment of pungency in the evolution of chili peppers.

Integrated transcriptomic and metabolomic analyses revealed the role of SlMYC2 in tomato (Solanum lycopersicum L.) fruit development and ripening

Transcription factor (TF) MYC2 is a fundamental regulator of the jasmonic acid (JA) signaling pathway and has a role in plant development and stress regulation. However, a comprehensive understanding of MYC2 regulatory role in fruit development and ripening is still lacking. In this study, the integrative and comparative analysis was performed on the transcriptome and metabolome of wild-type (WT) and SlMYC2 knockout tomato fruit at mature green and red ripening stages to uncover the function of SlMYC2. A total of 764 metabolites and 30,280 annotated unigenes were identified. The differential accumulated metabolites (DAMs) and differentially expressed genes (DEGs) caused by SlMYC2 mutation were 32.3 % and 159.8 % higher in red ripening fruit than in mature green fruit, respectively. From the mature green to red ripening stages of tomato fruit, KEGG enrichment analysis revealed that the DEGs affected by SlMYC2 were primarily involved in photosynthesis, carbohydrate metabolism, phenylpropanoid pathway, carotenoid biosynthesis, and plant hormone signal transduction. In addition, there are 36 TFs families in these DEGs, mainly including MYB_related, MYB, bHLH, B3, ERF, NAC, HB-other, WRKY and bZIP. Furthermore, the co-expression and promoter analysis indicated that MYB44, PLA1, WRKY17, LOX2, PPA1-LIKE, JAZ, ACSL1 and PYL4 may play an important role in the aforementioned metabolic pathways regulated by SlMYC2. Overall, these findings indicate that many key metabolic pathways, transcription factors, and genes may be governed by SlMYC2, potentially being related to fruit development, ripening, quality and stress resistance mechanisms. This study provides new insights into the function of MYC2 and lays a foundation for further research on the molecular mechanism underlying fruit development and ripening.

Colored Shading Nets Differentially Affect the Phytochemical Profile, Antioxidant Capacity, and Fruit Quality of Piquin Peppers (Capsicum annuum L. var. glabriusculum)

Piquin pepper fruits, a semi-domesticated wild pepper species highly valued in Mexico, currently face the threat of unsustainable harvesting practices that endanger the species. For this reason, it is necessary to establish sustainable agricultural practices for the cultivation of these peppers. Solar radiation, a critical determinant in crop production, plays a crucial role in plant development, influencing a spectrum of physiological and morphological processes, including the synthesis of phytochemicals. Our study evaluated the effect of light manipulation through colored shading nets on the phytochemical profile, antioxidant capacity, and fruit quality of semi-domesticated piquin peppers at two maturation stages: immature and mature (green and red fruits). Our hypothesis posits that these shading treatments may induce changes in these fruits’ phytochemical composition and antioxidant properties, as well as quality. Our results indicate that the shading treatments and maturity stage have significant on capsaicinoid and carotenoid levels, with the highest levels observed in mature fruits. Notably, red fruits grown under black shading treatments resulted in the highest capsaicinoid levels. Carotenoid levels were higher in the black shading treatment during the first cycle, while in the second cycle, the blue shading treatment showed elevated carotenoid levels, suggesting that high irradiance conditions could reduce carotenoid contents. Although no significant differences were observed among the treatments in green fruits, in red fruits, both black and blue treatments exhibited the highest total phenolic compounds in both production cycles. Furthermore, the antioxidant capacity revealed that red fruits exhibited higher antioxidant levels than green fruits. Color analysis showed that red fruits had higher chroma and hue angle values, indicating their brighter and more intense red color than green fruits. The morphological changes in fruit width, length, and weight can be attributed to shading treatments and maturation stages. These results indicate the potential of piquin peppers to act as rich sources of bioactive compounds, emphasizing the benefits of shading as an effective strategy to improve the quality and quantity of phytochemical compounds in piquin peppers. Our findings provide substantial insights into the intricate relationship between maturation, shading treatments, and phytochemical composition, offering a path to improve the nutritional value and quality of piquin peppers.

Comparative Transcriptome Analysis Reveals Genes Associated with Alkaloid Diversity in Javanese Long Pepper (Piper retrofractum) Fruits

Alkaloids are a class of secondary metabolites that play multifaceted roles in plant physiology, including defense mechanisms and interactions with other organisms. The alkaloids from Piper retrofractum (Javanese long pepper) fruits offer potential alternatives to synthetic pesticides due to their natural origin and insecticide properties. However, information on particular alkaloid biosynthesis pathways is required to enhance individual alkaloid production via metabolic engineering. Here, we perform HPLC profiling to demonstrate that fruit ripening influences the alkaloid diversity in P. retrofractum. De novo transcriptomic profiling of young, green mature, and red ripened fruits revealed that the piperine biosynthesis pathway genes were highly upregulated in the mature fruits. However, an enhanced accumulation of methyl piperate and guineensine in the ripened fruit was observed, entailing ripening-related differential gene expression to synchronize the alkaloid biosyntheses. Gene expression clustering and functional enrichment analysis identified a large group of genes involved in diverse biosynthetic processes explicitly enriched in the ripened fruits. A cohort of genes encoding for “Alkaloid Biosynthesis”, remarkably upregulated in the ripening fruits, indicates they may function directly in alkaloid diversity during a later stage of fruit development. This study provides the basis for metabolic engineering to enhance alkaloid diversity and production.

Determination of Phytochemical Contents in Extracts from Different Growth Stages of Oroxylum indicum Fruits Using HPLC-DAD and QAMS Methods.

Flavones are major compounds found in several parts of Oroxylum indicum (O. indicum). The quantification of multiple components by one marker (QAMS) method and the high-performance liquid chromatography (HPLC) method were developed for the quantitative analysis of extracts from the young fruits, green mature fruits, dry pod coats and seeds of O. indicum. Oroxin A, oroxin B and chrysin-7-O-glucuronide were identified in the O. indicum extracts. Oroxylin A and 5-hydroxymethylfurfural were isolated and structurally identified from the pod coat and young fruit extracts, respectively. From the HPLC analysis of the seven major flavones in the extracts, baicalin was the major compound in all extracts investigated (0.4-11% w/w of the extract). All flavone contents were low in the young fruit extract (<1% w/w of the extract). The green mature fruit and dry pod coat extracts showed similar constituent compositions. They contained small amounts of baicalin and oroxylin A, which were found only in these two extracts. Oroxylin A could be used as a marker to indicate the maturity of O. indicum fruits, while 5-hydroxymethylfurfural could be used as a marker for the young fruits. Baicalin was found to be a suitable single marker to calculate the contents of all flavones in the O. indicum extracts.

Quantitative proteomic analysis of tomato fruit ripening behavior in response to exogenous abscisic acid.

To determine how abscisic acid (ABA) affects tomato fruit ripening at the protein level, mature green cherry tomato fruit were treated with ABA, nordihydroguaiaretic acid (NDGA), or sterile water (control, CK). The proteomes of treated fruit were analyzed and quantified using tandem mass tags (TMTs) at 7 d after treatment, and the gene transcription abundances of differently expressed proteins (DEPs) were validated with qRT-PCR. The postharvest tomato fruit underwent faster color transformation and ripening than the CK when treated with ABA. In total, 6310 proteins were identified among the CK and treatment groups, of which 5359 were quantified. Using a change threshold of 1.2 or 0.83 times, 1081 DEPs were identified. Among them, 127 were upregulated and 127 were downregulated in the ABA vs CK comparison group. According to KEGG and protein-protein interaction network analyses, the ABA-regulated DEPs were primarily concentrated in the photosynthesis system and sugar metabolism pathways, and 102 DEPs associated with phytohormones biosynthesis and signal transduction, pigment synthesis and metabolism, cell wall metabolism, photosynthesis, redox reactions, allergens, and defense responses were identified in the ABA vs CK and NDGA vs CK comparison groups. ABA affects tomato fruit ripening at the protein level to some extent. The results of this study provided comprehensive insights and datas for further research on the regulatory mechanism of ABA in tomato fruit ripening. This article is protected by copyright. All rights reserved.

Production of plant-based milk from local almond nuts (&lt;em&gt;Terminalia catappa L&lt;/em&gt;.) and evaluation of its sensory and nutritional properties

An experiment was conducted to investigate the possibility of making plant-based milk using Local Almond (Terminalia catappa L.) nuts. Harvested nuts were cleaned, shelled and, separated into two sets based on their maturity stage: well-ripened and mature-green. Local Almond nuts at both maturity stages were blanched and blended with water at a ratio of 1:2 (w/w), and two different plant-based milk samples were prepared as T1, from well-ripened and T2, from mature-green fruit kernels. The sensory evaluation of prepared kernel-based milk samples was conducted, occupying a panel of 30 semi-trained members using a five-point hedonic scale. The product’s appearance, odour, flavour, mouthfeel, and overall acceptability were tested and analyzed using the Friedman test. The proximate composition of the prepared plant-based milk samples was determined in triplicates, and the energy content of the milk samples was estimated based on their nutritional values and was compared with those of Cow’s milk. Data were analyzed using ANOVA procedures at a 5% significance level. Obtained sensory data revealed that among two milk samples, milk prepared from well-ripened Local Almond kernel (T1) was recorded as the best sample except for aroma for all organoleptic attributes. The proximate analysis found that the crude protein, crude fat and crude fiber content of both T1 and T2 Local Almond milk samples were higher than those of Cow’s milk. Among the samples, the T1 showed the highest crude fat content (13.30 ± 0.01%), whereas T2 showed the highest crude protein content (7.40 ± 0.00%). Carbohydrate content of both T1 (2.09± 0.00%) and T2 (1.20± 0.00%) was less than that of cow’s milk (4.80 ± 0.01%). The study suggests mixing milk extracted from mature green fruits and well-ripened fruit kernels to improve the final nutritional quality of Local Almond milk. This study reveals the requirement for further studies related to Local Almond kernel-based milk as a good source of plant-based milk and a potential substitute for Cow’s milk.

Analysis of endogenous hormones in different organs reveals the critical role of phthalanilic acid in the yield and quality of pepper (Capsicum annuum) fruits

Phthalanilic acid (PPA), a plant growth regulator, has advantageous biological effects on fruit trees. However, little is known about its effects on vegetables. Thus, field trials were conducted on pepper (Capsicum annuum) plants by spraying with PPA at concentrations of 133.3, 200.0, and 266.7 mg·L−1. The key physiological indicators of peppers were investigated, including the number of flowers and fruits, yield, yield components, quality, and endogenous hormones. Results showed that PPA greatly boosted the number of flowers and fruits on pepper plants. The fruit shape index, dry matter content, single fruit weight, and yield in the PPA treatment of 133.3 mg·L−1 were particularly higher than those of the control, with increasing rates of 28.73%, 22.97%, 26.85%, and 35.75%, respectively. PPA considerably decreased the levels of titratable acid and nitrate while noticeably increasing the levels of soluble protein, soluble sugar, l-ascorbic acid, and capsaicin in mature green or red pepper fruits. PPA may also increase the levels of indole-3-acetic acid (IAA) in flowers, buds, and leaves, elevate the levels of abscisic acid (ABA) in leaves, raise the levels of zeatin riboside (ZR) in young fruits, but decrease the ABA content in buds. PPA actively controls fruit quality and yield in the concentration range of 133.3–200.0 mg·L−1. This beneficial outcome might ultimately be connected to the regulation of endogenous hormones.

Postharvest quality and prolong storage time of atemoya (Annona squamosa x A. cherimola hybrids) fruit: coating with D-limonene nanoemulsion edible film

ABSTRACT Atemoya (Annona squamosa x A. cherimola hybrid) is a typical climacteric fruit that has a high respiration rate after harvest, short storage life, and is highly susceptible to fruit cracking and rot. Therefore, this study was intended to apply D-limonene nanoemulsion coating on fruit to prolong the storage life, reduce spoilage, and facilitate the expansion of the market. Green mature atemoya fruit coated with different concentrations of D-limonene nanoemulsion (0.25%, 0.5%, 1.0%, 1.5%, and control) was stored in a 14°C refrigerator for relevant analysis and investigation. The results showed that the use of 0.25% D-limonene nanoemulsion inhibited the browning on the fruit surface, and reduced physiological metabolisms. The browning phenomenon on the fruit surface increased as the D-limonene concentration ratio increases. Since the high concentration caused damage to the peel cells, 0.25% D-limonene was chosen as optimum for atemoya coating. The fruit of atemoya maintained green peel color (L × 28.6, a × 6.63, b × 12.3) after storage at 14°C for 21 days with 0.25% D-limonene nanoemulsion coating. At the same time, after 0.2% D-limonene nanoemulsion coating, the weight loss rate was about % less than that of the control group (0.25% treatment was 11.3%; control was 14.2%) and high pectin content (0.25% treatment was 16.9 mg AGA g−1AIS−1; control was 9.89 mg AGA g−1AIS−1). Coating of D-limonene nanoemulsion can reduce the physiological response of atemoya fruits after harvesting, prolong the storage time, and increase the feasibility of their export. From the experimental results, D-limonene showed the potential to be widely used in fruit preservation agents in the future.

Location of seed spoilage in mango fruit using X-ray imaging and convolutional neural networks

Detection of the internal damage and insect infestation on intact mango fruit during harvesting, storage, and exportation is particularly challenging. Visual comparison of infestation by spot detection has proven unreliable in determining the presence of insects in seeds and the extent of spoilage in the fruit. The study aimed toward identifying a non-destructive, rapid, and correct method for detecting spoilage in mango seeds. Ninety-eight (98) mature green mango fruits were harvested from a farm (Kintampo, Ghana) for the experiment. The mangoes were numbered for photographic and X-ray imaging. The images were visually examined and classified based on morphology into mango fruit with good seed and bad seed. The dataset was then augmented into 8000 images and split into train (4000) and test (4000) sets. A VGG16 Deep Convolutional Neural Network (DCNN) model was trained, tested, cross-validated (five-fold), and evaluated by saliency maps on visualization algorithm, Grad-weighted Class Activation Mapping, Grad-CAM, and the Confusion matrix to ascertain its capacity to identify bad seed from good seed. The model achieved an accuracy rate of 97.66% and 0.988 area under the receiver operations characteristics curve. Further application of this model in the mango industry could promote non-destructive early detection of seed deterioration on the field and enhance the quality of products throughout the postharvest supply chain.

Genetics of destemming in pepper: A step towards mechanical harvesting.

Introduction: The majority of peppers in the US for fresh market and processing are handpicked, and harvesting can account for 20-50% of production costs. Innovation in mechanical harvesting would increase availability; lower the costs of local, healthy vegetable products; and perhaps improve food safety and expand markets. Most processed peppers require removal of pedicels (stem and calyx) from the fruit, but lack of an efficient mechanical process for this operation has hindered adoption of mechanical harvest. In this paper, we present characterization and advancements in breeding green chile peppers for mechanical harvesting. Specifically, we describe inheritance and expression of an easy-destemming trait derived from the landrace UCD-14 that facilitates machine harvest of green chiles. Methods: A torque gauge was used for measuring bending forces similar to those of a harvester and applied to two biparental populations segregating for destemming force and rate. Genotyping by sequencing was used to generate genetic maps for quantitative trait locus (QTL) analyses. Results: A major destemming QTL was found on chromosome 10 across populations and environments. Eight additional population and/or environment-specific QTL were also identified. Chromosome 10 QTL markers were used to help introgress the destemming trait into jalapeño-type peppers. Low destemming force lines combined with improvements in transplant production enabled mechanical harvest of destemmed fruit at a rate of 41% versus 2% with a commercial jalapeńo hybrid. Staining for the presence of lignin at the pedicel/fruit boundary indicated the presence of an abscission zone and homologs of genes known to affect organ abscission were found under several QTL, suggesting that the easy-destemming trait may be due to the presence and activation of a pedicel/fruit abscission zone. Conclusion: Presented here are tools to measure the easy-destemming trait, its physiological basis, possible molecular pathways, and expression of the trait in various genetic backgrounds. Mechanical harvest of destemmed mature green chile fruits was achieved by combining easy-destemming with transplant management.

Postharvest light-induced flavonoids accumulation in mango (Mangifera indica L.) peel is associated with the up-regulation of flavonoids-related and light signal pathway genes.

Flavonoids are important secondary metabolites in plants and light is a crucial environmental factor regulating flavonoids biosynthesis. However, effect of light on the different flavonoids compositions accumulation in mango and the relevant molecular mechanism still need to be clarified. In this study, green-mature fruits of red mango cultivar 'Zill' were subjected to postharvest light treatment, and fruit peel color, total soluble solids content, total organic acid, and firmness of flesh were measured. The flavonoids metabolites profile, and the expression of flavonoids-related genes and light signal pathway genes were also analyzed. Results showed that light treatment promoted the red coloration of fruit peel and increased the total soluble solids content and firmness of flesh. The concentration of flavonols, proanthocyanidins and anthocyanins, and expression of key flavonoids biosynthetic genes including MiF3H, MiFLS, MiLAR, MiANS, MiUFGT1, and MiUFGT3 were significantly induced by light. The MYBs regulating flavonols and proanthocyanidins, i.e. MiMYB22 and MiMYB12, as well as the key light signal pathway transcription factors (TFs) MiHY5 and MiHYH, were identified in mango. The transcription of MiMYB1, MiMYB12, MiMYB22, MiHY5 and MiHYH was up-regulated by light. Our results provide a postharvest technology to improve mango fruit appearance quality, and are helpful to reveal the molecular mechanism of light-induced flavonoids biosynthesis in mango.

Gene actions of resistance to anthracnose (Colletotrichum acutatum) of six F1 hybrid chili cultivars at the mature green fruit stage

Gene actions of resistance to anthracnose (<i>Colletotrichum acutatum</i>) of six F₁ hybrid chili cultivars at the mature green fruit stage

Genome-wide analysis of the polyphenol oxidase gene family reveals that MaPPO1 and MaPPO6 are the main contributors to fruit browning in Musa acuminate.

Polyphenol oxidases (PPOs), which are widely present in plants, play an important role in the growth, development, and stress responses. They can catalyze the oxidization of polyphenols and result in the browning of damaged or cut fruit, which seriously affects fruit quality and compromises the sale of fruit. In banana (Musa acuminata, AAA group), 10 PPO genes were determined based on the availability of a high-quality genome sequence, but the role of PPO genes in fruit browning remains unclear. In this study, we analyzed the physicochemical properties, gene structure, conserved structural domains, and evolutionary relationship of the PPO gene family of banana. The expression patterns were analyzed based on omics data and verified by qRT-PCR analysis. Transient expression assay in tobacco leaves was used to identify the subcellular localization of selected MaPPOs, and we analyzed the polyphenol oxidase activity using recombinant MaPPOs and transient expression assay. We found that more than two-thirds of the MaPPO genes had one intron, and all contained three conserved structural domains of PPO, except MaPPO4. Phylogenetic tree analysis revealed that MaPPO genes were categorized into five groups. MaPPOs did not cluster with Rosaceae and Solanaceae, indicating distant affinities, and MaPPO6/7/8/9/10 clustered into an individual group. Transcriptome, proteome, and expression analyses showed that MaPPO1 exhibits preferential expression in fruit tissue and is highly expressed at respiratory climacteric during fruit ripening. Other examined MaPPO genes were detectable in at least five different tissues. In mature green fruit tissue, MaPPO1 and MaPPO6 were the most abundant. Furthermore, MaPPO1 and MaPPO7 localized in chloroplasts, and MaPPO6 was a chloroplast- and Endoplasmic Reticulum (ER)-localized protein, whereas MaPPO10 only localized in the ER. In addition, the enzyme activity in vivo and in vitro of the selected MaPPO protein showed that MaPPO1 had the highest PPO activity, followed by MaPPO6. These results imply that MaPPO1 and MaPPO6 are the main contributors to banana fruit browning and lay the foundation for the development of banana varieties with low fruit browning.