Stages Of Fruit Ripening Research Articles

Genome-Wide Analysis of the Common Fig (Ficus carica L.) R2R3-MYB Genes Reveals Their Structure, Evolution, and Roles in Fruit Color Variation.

The R2R3-MYB transcription factor (TF) family is crucial for regulating plant growth, stress response, and fruit ripening. Although this TF family has been examined in a multitude of plants, the R2R3-MYB TFs in Ficus carica, a Mediterranean fruit species, have yet to be characterized. This study identified and classified 63 R2R3-MYB genes (FcMYB1 to FcMYB63) in the F. carica genome. We analyzed these genes for physicochemical properties, conserved motifs, phylogenetic relationships, gene architecture, selection pressure, and gene expression profiles and networks. The genes were classified into 29 clades, with members of the same clade showing similar exon-intron structures and motif compositions. Of the 54 orthologous gene pairs shared with mulberry (Morus notabilis), 52 evolved under negative selection, while two pairs (FcMYB55/MnMYB20 and FcMYB59/MnMYB31) experienced diversifying selection. RNA-Seq analysis showed that FcMYB26, FcMYB33, and FcMYB34 were significantly overexpressed in fig fruit peel during maturation phase III. Weighted gene co-expression network analysis (WGCNA) indicated that these genes are part of an expression module associated with the anthocyanin pathway. RT-qPCR validation confirmed these findings and revealed that the Tunisian cultivars 'Zidi' and 'Soltani' have cultivar-specific R2R3-FcMYB genes highly overexpressed during the final stage of fruit maturation and color acquisition. These genes likely influence cultivar-specific pigment synthesis. This study provides a comprehensive overview of the R2R3-MYB TF family in fig, offering a framework for selecting genes related to fruit peel color in breeding programs.

Mapping and cloning of pepper fruit color-related genes based on BSA-seq technology.

Fruit color is an important qualitative trait that greatly influences the marketability of peppers. Fruit color can be divided into two categories. Green fruit color denotes commercial maturity, whereas ripe fruit indicates physiological maturity. Herein, segregation populations were created using the 'D24' with pale green in the green fruit stage, orange in the mature fruit stage, and 'D47' with green in the green fruit stage and red in the mature fruit stage. BSA-seq and genetic linkage map analysis revealed green fruit color was linked to (gyqtl1.1) on Chr1 and (gyqtl10.1) on Chr10, while mature fruit color was linked to Chr6. Using functional annotation, sequence, and expression analysis, we speculate that an SNP mutation in the CapGLK2 gene at the gyqtl10.1 interval could initiate premature termination of translation, thus yielding green to pale green fruits in D47. Conversely, the orange color in mature D24 fruits is due to the Indel-mediated premature termination of translation of the CapCCS gene. Our research offers a theoretical foundation for choosing different varieties of pepper fruit based on their color.

Influence of Vine Decline Disease on the Amino Acid Metabolism of Watermelon Fruit

Vine decline (VD) is a recalcitrant syndrome of watermelon, melon, and other cucurbits, often associated with soil-borne pathogens such as Monosporascus cannonballus and characterized by root necrosis, leaf chlorosis, and wilting at the later stage of fruit maturation. The present study examined VD’s effects on watermelon fruits’ metabolism. The VD-affected watermelon fruits had significantly lower lycopene and total solid contents. Still, polyphenols content and total antioxidant activities were comparable with the controls, suggesting that VD inhibited the ripening processes but maintained defensive processes in the fruits. The VD fruits showed a lower calcium level than the controls, while the contents of other major nutrition minerals were not significantly altered. The VD fruits had a lower content of total amino acids, and their composition was characterized by an increase in the percentage fractions for several amino acids, including citrulline, which may reflect the physiological response to the VD-related water deficit condition. The principal component analysis distinguished amino acid profiles between the VD and control fruits, demonstrating that VD significantly influenced their amino acid metabolisms. The present study revealed that VD imposed characteristic impacts on the biochemical behaviors in the watermelon fruits.

Sustained carbon import supports sugar accumulation and anthocyanin biosynthesis during fruit development and ripening in blueberry (Vaccinium ashei)

Fruit ripening is a highly coordinated process involving molecular and biochemical changes that collectively determine fruit quality. The underlying metabolic programs and their transitions leading to fruit ripening remain largely under-characterized in blueberry (Vaccinium sp.), which exhibits atypical climacteric behavior. In this study, we focused on sugar, acid and anthocyanin metabolism in two rabbiteye blueberry cultivars, Premier and Powderblue, during fruit development and ripening. Concentrations of the three major sugars, sucrose (Suc), glucose (Glc), and fructose (Fru) increased steadily during fruit development leading up to ripening, and increased dramatically by around 2-fold in ‘Premier’ and 2- to 3-fold in ‘Powderblue’ during the final stage of fruit ripening. Starch concentration was very low throughout fruit development in both cultivars indicating that it does not serve the role of a major transitory carbon (C) storage form in blueberry fruit. Together, these patterns indicate continued import of C, likely in the form of Suc, throughout blueberry fruit development. Concentrations of the predominant acids, malate and quinate, decreased during ripening, and may contribute to increased shikimate biosynthesis which, in-turn, allows for downstream phenylpropanoid metabolism leading to anthocyanin synthesis. Consistently, anthocyanin concentrations were highest in fully ripened blue fruit. Weighted gene co-expression network analysis (WGCNA) was performed using a ‘Powderblue’ fruit ripening transcriptome and targeted fruit metabolite concentration data. A ‘dark turquoise’ module positively correlated with sugars and anthocyanins, and negatively correlated with acids (malate, quinate), was identified. Gene Ontology (GO) enrichment analysis of this module identified transcripts related to sugar, acid, and phenylpropanoid metabolism pathways. Among these, increased transcript abundance of a VACUOLAR INVERTASE during ripening was consistent with sugar storage in the vacuole. In general, transcript abundance of the glycolysis pathway genes was upregulated during ripening. The transcript abundance of PHOSPHOENOLPYRUVATE (PEP) CARBOXYKINASE increased during fruit ripening and was negatively correlated with malate concentration, suggesting increased malate conversion to PEP, which supports anthocyanin production during fruit ripening. This was further supported by the co-upregulation of several anthocyanin biosynthesis-related genes. Together, this study provides insights into important metabolic programs, and their underlying gene expression patterns during fruit development and ripening in blueberry.

In vitro antimicrobial and antioxidant activities of essential oil extracts from underutilized Zanthoxylum ovalifolium tutcher fruits: Prospective applications in the food industry

Zanthoxylum ovalifolium fruits and its oils are being used in traditional foods as flavoring agent. So, the present investigation was taken to evaluate the potential of essential oils extracted from fruits activity against food borne spoilage microbes. Phytochemical screening revealed the presence of flavonoids and phytosterols. GC-MS results showed the presence of a total of 20 compounds, including Oleoyl chloride in the oil extracted from young fruit and Bis(2-ethylhexyl) phthalate in both oils. The LC-MS results revealed a total of 48 compounds, highlighting variations in composition between ZEY and ZEM, likely due to the fruit's maturity stage. DPPH free radical scavenging potential of young fruit essential oils extract showed highest percentage of scavenging activity and IC50 values. The antimicrobial activities of the essential oils were evaluated against bacterial and fungal strains by well diffusion method. S. aureus showed highest zone of inhibition and all fungal strains showed excellent inhibition compared to standard. These essential oils have appreciated capability of suppressing growth of wide variety of food borne microbes in turn scavenging the free radicals released by them. Derived from natural sources, this essential oil offers a promising alternative for extending the shelf life of food products.

Sex-Dependent Rhizosphere Microbial Dynamics and Function in Idesia polycarpa through Floral and Fruit Development

Male Idesia polycarpa, which display distinct morphological and physiological traits, exhibit greater adaptability to stressful environments than females. However, the connection between this adaptability and rhizosphere processes remains unclear. Here, we investigate the differences in root bacterial community structures between male and female plants at different developmental stages, identifying bacterial strains associated with plant sex through functional predictions. This study aims to inform the optimal allocation of male and female plants during cultivation and provide a theoretical basis for sex identification and breeding. Samples from seven-year-old male and female plants were collected during the flowering (May) and fruit ripening (October) stages. Rhizosphere nutrient content and bacterial diversity were analyzed using Illumina high-throughput sequencing technology. The results demonstrate that total nitrogen (TN), total carbon (TC), and available potassium (AK) varied between sexes at different times. No significant differences between male and female plants were observed in the Shannon, Simpson, and Chao1 indexes during the flowering period. However, the Chao1 and Shannon indexes were significantly higher at fruit maturity in male rather than female plants. The predominant phyla of rhizosphere bacteria were Pseudomonadota, Acidobacteriota, and Actinomycetes. Interestingly, from flowering to fruit ripening, the dominant phyla in both male and female plants shifted from Actinomycetes to Pseudomonadota. A significant correlation was observed between pH and AK and rhizosphere bacteria (p < 0.05), with metabolism being the main functional difference. This study provides preliminary insights into the functional predictions and analyses of bacteria associated with Idesia polycarpa. The above findings lay the groundwork for further investigation into the sex-specific differences in microbial flora across different developmental stages, elucidating the mechanisms underlying flora changes and offering theoretical support for the high-quality management of Idesia polycarpa.

A logistic model for precise tomato fruit-growth prediction based on diameter-time evolution

Monitoring tomato fruit growth in large greenhouse environments is crucial for estimating harvest volume and maximising labour efficiency. Mathematical modelling is commonly used to characterise crop and fruit growth and to understand crop responses to environmental influences. This study presents a logistic approach for estimating tomato fruit maturity based on fruit diameter. A set of logistic models were evaluated, and their precision and ability to forecast tomato fruit growth were analysed. Non-linear least square regression was used to fit each model to individual tomato fruits from a sample of over 600 fruits of two species (small and large fruit-bearing tomatoes) grown within one year. The focus was on fruit diameter and the necessary measurement precision for fruit maturity estimation. Low-dispersion variables were identified within our logistic model functions, and fruit species-specific model parameters were determined. Furthermore, we reduced the number of regression variables by identifying parameters of low variance. This allowed for high prediction precision (>80%) at the early fruit maturity stages (<30%). The fruit diameter data were collected manually using a caliper. Our results establish an upper limit for the measurement precision of automated fruit size estimation approaches utilising photogrammetry, with an optical range of 98% for 3 mm and 90% for 5 mm precision.

Changes in redox status in raspberry (Rubus idaeus L.) fruit during ripening

The knowledge of the mechanisms affecting the process of berry fruit ripening is important, not only to correctly determine the appropriate date of harvest, at which the fruit is most palatable and characterized by adequate shelf-life stability, but also, to develop new strategies of regulating the ripening process before harvesting. It is recognized that berry fruit quality and its post-harvest shelf-life depend on the cellular redox homeostasis. We, therefore, decided to conduct a comprehensive analysis of the level of oxidative stress status in the raspberry fruit proper at different stages of fruit ripening, from green to overripe fruit. We assessed both the level of typical oxidative stress markers, i.e. ROS production, expression of antioxidant enzymes, degree of cell damage, as well as the expression of selected proteins involved in the energy, glutathione, and polyphenols metabolism. We found two stage-related peaks of ROS production. The first - in green fruit, which corresponded to the maximum expression of antioxidant enzymes (MnSOD, CAT), PARP-1, as well as proteins related to glutathione biosynthesis (GS, γ-GC), autophagy (ATG-8) and ubiquitination (UBQ-11). The second one, in the overripe fruit, was responsible for the intensification of oxidative modifications of cell components, i.e. lipids, proteins, and DNA, as well as the loss of low molecular-weight antioxidants. The fruit ripening process, in turn, was manifested by a strong increase in the expression of proteins involved in the biosynthesis of polyphenols (PAL, CHS), cellular respiration (ACO-1, Cyt-C-ox, ATPase), ethylene biosynthesis and signaling (SAMs, EIN-2) and increasing amounts of ABA.

Soil moisture content estimation of drip-irrigated citrus orchard based on UAV images and machine learning algorithm in Southwest China

Soil moisture content (SMC), as a pivotal component in the energy and matter exchange processes within the soil-plant-atmosphere continuum, plays a crucial role in surface water dynamics, energy fluxes, and carbon cycling within ecosystems. The development of remote sensing technology has offered new perspectives for monitoring soil moisture at regional scales. Unmanned aerial vehicles (UAV) equip with multispectral have distinct advantages for vegetation monitoring, including rapidity and cost-effectiveness, which has superior applicability and practicality. Therefore, in a 5a "Daya" late-maturing citrus orchard, the vegetation index (VI) and texture feature (TF) information of citrus canopy based on UAV multi-spectral images were extracted, and soil and plant analyzer development (SPAD) of citrus was collected. These different data sources were integrated into the framework of the random forest algorithm (RF) and genetic algorithm-optimized random forest (GA-RF) to evaluate the accuracy of surface SMC (SSMC) estimation in citrus orchard. The Biswas model was utilized to simulate the root zone SMC (RSMC). The spatiotemporal variations of SMC in citrus orchard were analyzed, and the potential of low-cost sensor-equipped drones in rapidly acquiring spatial and temporal distribution information of SMC at a large regional scale was explored. The results indicated that the GA-RF models outperformed the RF models in estimating citrus orchard SMC (with R2 ranging from 0.502 to 0.949 and RMSE ranging from 0.552 % to 3.166 % for GA-RF, compared to R2 ranging from 0.430 to 0.936 and RMSE ranging from 0.587 % to 3.449 % for the RF). The GA-RF models using VI+SPAD as inputs exhibited the best performance for SMC at depths of 5 cm, 10 cm, 20 cm and 40 cm (SMC5, SMC10, SMC20 and SMC40) across citrus growth stages (R2 ranging from 0.793 to 0.949 at 5 cm, R2 ranging from 0.702 to 0.938 at 10 cm, R2 ranging from 0.714 to 0.927 at 20 cm). In bud bust to flowering, young fruit and fruit maturation stages (stage Ⅰ, ⅠⅠ and ⅠⅤ), all models demonstrated good accuracy in estimating SMC at depth of 10 cm (R2 ranging from 0.567 to 0.908 in stage Ⅰ, with R2 ranging from 0.681 to 0.916 in stage ⅠⅠ and R2 ranging from 0.579 to 0.938 in stage ⅠⅤ). In fruit expansion stage (stage III), the models performed best in predicting SMC5 (R2 ranging from 0.698 to 0.861). The Biswas model was constructed to simulate SMC40 by utilizing the inverted SMC10 and SMC20, thereby generating spatiotemporal distribution maps of SMC at different depths in citrus orchard. The SSMC was susceptible to environmental factors, exhibiting significant spatiotemporal heterogeneity. In summary, this study illustrated that the integration of multiple data sources into GA-RF enhanced the estimation performance of SMC at different growth stages of late-maturing citrus orchard in the Southwest China. Additionally, it enabled the rapid and efficient monitoring of spatiotemporal variations in SMC, providing an effective method and practical foundation for precision irrigation and improved water use efficiency.

Mapping and transcriptomic profiling reveal that the KNAT6 gene is involved in the dark green peel colour of mature pumpkin fruit (Cucurbita maxima L.).

We identified a 580bp deletion of CmaKNAT6 coding region influences peel colour of mature Cucurbita maxima fruit. Peel colour is an important agronomic characteristic affecting commodity quality in Cucurbit plants. Genetic mapping of fruit peel colour promotes molecular breeding and provides an important basis for understanding the regulatory mechanism in Cucurbit plants. In the present study, the Cucurbita maxima inbred line '9-6' which has a grey peel colour and 'U3-3-44' which has a dark green peel colour in the mature fruit stage, were used as plant materials. At 5-40days after pollination (DAP), the contents of chlorophyll a, chlorophyll b, total chlorophyll and carotenoids in the 'U3-3-44' peels were significantly greater than those in the '9-6' peels. In the epicarp of the '9-6' mature fruit, the presence of nonpigmented cell layers and few chloroplasts in each cell in the pigmented layers were observed. Six generations derived by crossing '9-6' and 'U3-3-44' were constructed, and the dark green peel was found to be controlled by a single dominant locus, which was named CmaMg (mature green peel). Through bulked-segregant analysis sequencing (BSA-seq) and insertion-deletion (InDel) markers, CmaMg was mapped to a region of approximately 449.51kb on chromosome 11 using 177 F2 individuals. Additionally, 1703 F2 plants were used for fine mapping to compress the candidate interval to a region of 32.34kb. Five coding genes were in this region, and CmaCh11G000900 was identified as a promising candidate gene according to the reported function, sequence alignment, and expression analyses. CmaCh11G000900 (CmaKNAT6) encodes the homeobox protein knotted-1-like 6 and contains 4 conserved domains. CmaKNAT6 of '9-6' had a 580bp deletion, leading to premature transcriptional termination. The expression of CmaKNAT6 tended to increase sharply during the early fruit development stage but decrease gradually during the late period of fruit development. Allelic diversity analysis of pumpkin germplasm resources indicated that the 580bp deletion in the of CmaKNAT6 coding region was associated with peel colour. Subcellular localization analysis indicated that CmaKNAT6 is a nuclear protein. Transcriptomic analysis of the inbred lines '9-6' and 'U3-3-44' indicated that genes involved in chlorophyll biosynthesis were more enriched in 'U3-3-44' than in '9-6'. Additionally, the expression of transcription factor genes that positively regulate chlorophyll synthesis and light signal transduction pathways was upregulated in 'U3-3-44'. These results lay a foundation for further studies on the genetic mechanism underlying peel colour and for optimizing peel colour-based breeding strategies for C. maxima.

Modeling Tomato Yield and Quality Responses to Water and Nitrogen Deficits with a Modified Crop Water Production Function

Increasingly severe crises, such as climate change, water scarcity and environmental pollution, pose significant challenges to global food security and sustainable agricultural development. For efficient and sustainable tomato cultivation management under resource constraints, quantitatively describing the relationship between yield-quality harvest and water-nitrogen application is practically beneficial. Two successive greenhouse experiments with three irrigation levels (1/3 FI, 2/3 FI, and full irrigation (FI)) and four nitrogen fertilizer treatments (0 FN, 1/3 FN, 2/3 FN, and full nitrogen (FN)) were conducted on tomatoes during the whole phenological stage. The tomato evapotranspiration and nitrogen application amount, yield, comprehensive quality, solid–acid ratio, and lycopene content were measured. Based on crop water production functions, three equation forms of water-nitrogen production functions containing 20 models were established and evaluated to predict tomato harvest parameters. The results show that water increased tomato yield while decreasing fruit quality, and the effect of nitrogen was primarily contrary. Water most significantly impacted tomato formation, and the interaction of water and nitrogen changed among different harvest parameters. Tomato yield and quality formation was more sensitive to water and nitrogen at the flowering and fruit maturation stages. Model Singh-2 outweighed other models for yield estimates, with an R2 of 0.71 and an RMSE of 0.11. Singh-Log, Singh-sigmoid and Rao-Root models were effective models for comprehensive quality, solid–acid ratio, and lycopene content prediction, with an R2 of 0.41, 0.62, and 0.42, and an RMSE of 0.33, 0.50, and 0.16, respectively. Finally, models in the form of f(ETi)·f(N) were ideal for tomato harvest prevision and are recommended for water and nitrogen management in tomato cultivation.

Quality evaluation of “Gấc” arils and peels according to the maturity and ripeness stages

Two parts (arils and peel) of “Gấc” fruit (Momordica cochinchinensis Spreng) were analyzed for their physicochemical properties from the stage when the fruit reached maturity to the next ripening stages. Understanding these characteristics can help identify maturity indicators and use them most effectively. Research results show that “Gấc” fruit reaches maturity at the 7th week (A1) after fruit set (WAFS). At this time, the diameter and weight of the fruit no longer increase. Subsequent changes represent a gradual color change from completely blue (A1) to completely red (A5) and dark red (A6), through three intermediate stages (from A2 to A4). “Gấc” peel synthesizes the highest lycopene content (131.72 µg/g) at stage A5 (11 WAFS) and the highest β-carotene content at both stages A4 and A5 (10 and 11 WAFS) compared to fruit at stage A1 (7 WAFS). Meanwhile, lycopene and β-carotene in arils reached the highest concentrations (1672.04±9.1 μg/g and 582.45±3.4 μg/g, respectively) at stage A5 (11 WAFS). The total polyphenol content (TPC) in “Gấc” fruit arils/peel and total chlorophyll in “Gấc” fruit peel gradually decrease through the ripening stages, the highest value was achieved when the fruit was mature (A1) and the lowest value in fully ripened fruit (A5). Although showing a decrease, “Gấc” fruit still maintained TPC content in arils and peels of 89% and 73%, respectively (stages A4 and A5). The antioxidant activity of both “Gấc” fruit arils and peel also showed similar activity. In addition, “Gấc” arils also contain the highest vitamin C content in the fully ripe fruit stage compared to other stages. Thus, harvesting “Gấc” fruit at stages A4 and A5 will have beneficial ingredients (lycopene, β-carotene, total polyphenol content and vitamin C) that are good for human health.

Variation in Soluble Sugars in Arabica Coffee Cherry Fruits.

The maturation of Arabica coffee fruits is influenced by both endogenous and external factors. The stage of fruit maturation affects the chemical composition of the beans, which in turn impacts the quality of the coffee beverage. During maturation, the fruit peel changes colour from green to red (cherry), signalling the optimal harvest time and suggesting high fruit quality. However, the degree of redness can vary, indicating different levels of maturity. This study aimed to explore the variation in soluble sugar accumulation in relation to the redness of coffee fruit tissues. We classified ripe fruits into six ripeness categories based on the intensity of the red colour of the epicarp, measured using a colourimeter. We analysed total soluble sugar, sucrose, and starch in three parts: coat (exocarp + mesocarp), coat juice (obtained by squeezing the coat), and beans. Our findings reveal that the variation in sugar in the endosperm does not correspond to changes in the coat, suggesting separate regulation of sugar accumulation, particularly sucrose, which is crucial for coffee quality. Our data indicate that there is no transfer of sucrose and reducing sugars from the red coat to the bean.

Haplotype-resolved genome assembly for tetraploid Chinese cherry (Prunus pseudocerasus) offers insights into fruit firmness.

Chinese cherry (Prunus pseudocerasus) holds considerable importance as one of the primary stone fruit crops in China. However, artificially improving its traits and genetic analysis are challenging due to lack of high-quality genomic resources, which mainly result from difficulties associated with resolving its tetraploid and highly heterozygous genome. Herein, we assembled a chromosome-level, haplotype-resolved genome of the cultivar 'Zhuji Duanbing', comprising 993.69Mb assembled into 32 pseudochromosomes using PacBio HiFi, Oxford Nanopore, and Hi-C. Intra-haplotype comparative analyses revealed extensive intra-genomic sequence and expression consistency. Phylogenetic and comparative genomic analyses demonstrated that P. pseudocerasus was a stable autotetraploid species, closely related to wild P. pusilliflora, with the two diverging ~18.34 million years ago. Similar to other Prunus species, P. pseudocerasus underwent a common whole-genome duplication event that occurred ~139.96 million years ago. Because of its low fruit firmness, P. pseudocerasus is unsuitable for long-distance transportation, thereby restricting its rapid development throughout China. At the ripe fruit stage, P. pseudocerasus cv. 'Zhuji Duanbing' was significantly less firm than P. avium cv. 'Heizhenzhu'. The difference in firmness is attributed to the degree of alteration in pectin, cellulose, and hemicellulose contents. In addition, comparative transcriptomic analyses identified GalAK-like and Stv1, two genes involved in pectin biosynthesis, which potentially caused the difference in firmness between 'Zhuji Duanbing' and 'Heizhenzhu'. Transient transformations of PpsGalAK-like and PpsStv1 increase protopectin content and thereby enhance fruit firmness. Our study lays a solid foundation for functional genomic studies and the enhancement of important horticultural traits in Chinese cherries.

Metabolites of blueberry roots at different developmental stages strongly shape microbial community structure and intra-kingdom interactions at the root-soil interface

The rhizosphere microorganisms of blueberry plants have long coexisted with their hosts under distinctively acidic soil conditions, exerting a profound influence on host performance through mutualistic symbiotic interactions. Meanwhile, plants can regulate rhizosphere microorganisms by exerting host effects to meet the functional requirements of plant growth and development. However, it remains unknown how the developmental stages of blueberry plants affect the structure, function, and interactions of the rhizosphere microbial communities. Here, we examined bacterial communities and root metabolites at three developmental stages (flower and leaf bud development stage, fruit growth and development stage, and fruit maturation stage) of blueberry plants. The results revealed that the Shannon and Chao 1 indices as well as community composition varied significantly across all three developmental stages. The relative abundance of Actinobacteria significantly increased by 10 % (p < 0.05) from stage 1 to stage 2, whereas that of Proteobacteria decreased significantly. The co-occurrence network analysis revealed a relatively complex network with 1179 edges and 365 nodes in the stage 2. Niche breadth was highest at stage 2, while niche overlap tended to increase as the plant developed. Furthermore, the untargeted metabolome analysis revealed that the number of differential metabolites of vitamins, nucleic acids, steroids, and lipids increased between stage 1 to stage2 and stage 2 to stage 3, while those for differential metabolites of carbohydrates and peptides decreased. Significant changes in expression levels of levan, L-glutamic acid, indoleacrylic acid, oleoside 11-methyl ester, threo-syringoylglycerol, gingerglycolipid B, and bovinic acid were highly correlated with the bacterial community structure. Collectively, our study reveals that significant alterations in dominant bacterial taxa are strongly correlated with the dynamics of root metabolites. These findings lay the groundwork for developing prebiotic products to enhance the beneficial effects of root microorganisms and boosting blueberry productivity via a sustainable approach.

Deciphering the role of fruit maturity, calcium and freezing on the nutritional and textural attributes of crisps from red guava

SummaryGuava (Psidiumguajava L.), being highly nutritious possesses commercial importance in the tropical and subtropical region of the world. The climacteric guava, however, records highest postharvest loss and needs to be processed for higher shelf life and utility. This study entails evaluation of fruit maturity stage and prior freezing for development of calcium enriched guava crisps through atmospheric frying. The sliced fruits (of three maturity stages) were subjected to vacuum impregnation to infuse maltodextrin, salt, ascorbic acid and calcium lactate. Fracturability and crispness was significantly affected by fruit maturity, freezing pre‐treatment and calcium impregnation. Freezing pre‐treatment enhanced the texture, decreased toughness and gave superior crisps with crunchy mouthfeel. While browning increased due to freezing pre‐treatment, calcium impregnation led to decreased browning. More than 15‐fold increase in the calcium content of crisps was realised upon 1% calcium lactate impregnation. The average ascorbic acid and lycopene retention in the crisps was 36.18 and 37.58%, respectively. Mature guava showed highest lycopene retention (43.07%) in crisps. Based on MANOVA analysis, all the main effects, two factor interaction and three factor interaction were statistically significant at 1% level. The first three PCs could explain 73.64% variation in data. The highest ascorbic acid retention, crispiness and sensory scores were recorded for crisps from ripe stage of guava fruits given freezing and calcium infusion pre‐treatments. Thus, ripe guava fruits could be converted to shelf stable and attractive crisps, which would provide essential nutrients and potential health benefits, ensuring off‐season availability of perishable guava in the form of crisps.

Integration of transcriptome and metabolome reveals regulatory mechanisms of volatile flavor formation during tomato fruit ripening

Tomato is an important economic crop all over the world. Volatile flavors in tomato fruit are key factors influencing consumer liking and commercial quality. However, the regulatory mechanism controlling the volatile flavors of tomatoes is still not clear. Here, we integrated the metabolome and transcriptome of the volatile flavors in tomato fruit to explore the regulatory mechanism of volatile flavor formation, using wild and cultivated tomatoes with significant differences in flavors. A total of 35 volatile flavor compounds were identified, based on the solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS). The content of the volatiles, affecting fruit flavor, significantly increased in the transition from breaker to red ripe fruit stage. Moreover, the total content of the volatiles in wild tomatoes was much higher than that in the cultivated tomatoes. The content variations of all volatile flavors were clustered into 10 groups by hierarchical cluster and Pearson correlation analysis (PCC). The fruit transcriptome was also patterned into 10 groups, with significant variations both from the mature green to breaker fruit stage and from the breaker to red ripe fruit stage. Combining the metabolome and the transcriptome of the same developmental stage of fruits by co-expression analysis, we found that the expression level of 1 182 genes was highly correlated with the content of volatile flavor compounds, thereby constructing two regulatory pathways of important volatile flavors. One pathway is tetrahydrothiazolidine N-hydroxylase (SlTNH1)-dependent, which is regulated by two transcription factors (TFs) from the bHLH and AP2/ERF families, controlling the synthesis of 2-isobutylthiazole in amino acid metabolism. The other is lipoxygenase (SlLOX)-dependent, which is regulated by one TF from the HD-Zip family, controlling the synthesis of hexanal and (Z)-2-heptenal in fatty acid metabolism. Dual-luciferase assay confirmed the binding of bHLH and AP2/ERF to their structural genes. The findings of this study provide new insights into volatile flavor formation in tomato fruit, which can be useful for tomato flavor improvement.

Evidence Supporting a Role of Alternative Splicing Participates in Melon (Cucumis melo L.) Fruit Ripening.

One key post-transcriptional modification mechanism that dynamically controls a number of physiological processes in plants is alternative splicing (AS). However, the functional impacts of AS on fruit ripening remain unclear. In this research, we used RNA-seq data from climacteric (VED, Harukei 3) and non-climacteric (PI, PS) melon cultivars to explore alternative splicing (AS) in immature and mature fruit. The results revealed dramatic changes in differential AS genes (DAG) between the young and mature fruit stages, particularly in genes involved in fruit development/ripening, carotenoid and capsaicinoid biosynthesis, and starch and sucrose metabolism. Serine/arginine-rich (SR) family proteins are known as important splicing factors in AS events. From the melon genome, a total of 17 SR members were discovered in this study. These genes could be classified into eight distinct subfamilies based on gene structure and conserved motifs. Promoter analysis detected various cis-acting regulatory elements involved in hormone pathways and fruit development. Interestingly, these SR genes exhibited specific expression patterns in reproductive organs such as flowers and ovaries. Additionally, concurrent with the increase in AS levels in ripening fruit, the transcripts of these SR genes were activated during fruit maturation in both climacteric and non-climacteric melon varieties. We also found that most SR genes were under selection during domestication. These results represent a novel finding of increased AS levels and SR gene expression during fruit ripening, indicating that alternative splicing may play a role in fruit maturation.

Vapour pressure deficit affects crop water productivity, yield, and quality in tomatoes

A high atmospheric vapour pressure deficit (VPD) hinders calcium absorption in tomatoes (Solanum lycopersicum L.), which severely reduces tomato yield, crop water productivity (WPcrop), and quality. Although reducing the VPD is effective for increasing tomato yield and water productivity, regulating the VPD is costly. Therefore, this study aimed to explore the effects of VPD regulation (high VPD=2.22 kPa, low VPD=0.95 kPa) during different growth stages on tomato WPcrop, yield, and quality to identify a VPD management method that saves costs and enhances the above parameters. The results showed that the yield was significantly positively correlated with fruit calcium absorption. Decreasing the VPD during the fruit expansion stage and increasing it during the flowering stage significantly increased calcium accumulation in the fruits, thereby improving tomato WPcrop, yield, and quality. Additionally, a high VPD during the flowering stage increased stomatal conductance and mesophyll conductance, thereby increasing intercellular and chloroplast CO2 concentrations and enhancing plant photosynthetic capacity, and reduced the stem water potential, leaf water potential, and leaf relative water content, thereby increasing the water potential difference, leaf hydraulic conductance, and calcium absorption. By integrating game theory and the technique for order of preference by similarity to ideal solution method, a comprehensive analysis of tomato appearance, nutrients, and flavour quality revealed that growing plants under a high VPD during the seedling, flowering, and fruit ripening stages and a low VPD during the fruit expansion stage not only enhanced the comprehensive tomato quality value but also maximally reduced the humidification cost. Conclusively, controlling the environmental VPD at 2.22 kPa during the seedling, flowering, and fruit ripening stages and at 0.95 kPa during the fruit expansion stage can effectively increase tomato WPcrop, yield, and quality. This study provides a theoretical basis for the environmental regulation of high-quality, efficient, and water-conserving cultivation of greenhouse tomatoes.

Antioxidant activity and 1H NMR profiling of leaves and fruits of Rhodomyrtus tomentosa from South Kalimantan, Indonesia

Abstract. Kuntorini EM, Triyasmono L, Astuti MD. 2024. Antioxidant activity and 1H NMR profiling of leaves and fruits of Rhodomyrtus tomentosa from South Kalimantan, Indonesia. Biodiversitas 25: 2020-2027. Rhodomyrtus tomentosa (Aiton) Hassk is a flowering plant belonging to Myrtaceae, native to southern and southeastern Asia. This study aims to evaluate and compare the antioxidant activity of leaves and fruits ethanol extracts of R. tomentosa (Ait.) Hassk from two locations, namely Banjar and Batola, South Kalimantan Province, Indonesia. The samples included old and young leaves and three stages of fruit maturity, namely green, red, and purple. 1H NMR spectroscopy was used to identify the chemical profile of extracts, which comprised organic acids, carbohydrates, amino acids, and phenolic compounds. Antioxidant capacity was assessed with DPPH, which showed intensity differences in aromatic shifts in leaves and fruits for both regions. Young leaves and green fruits had higher intensity than old leaves and red and purple fruits, correlating with antioxidant capacity. Analysis of 1H NMR spectra of young and old leaf extracts identified vital metabolites, such as gallic acid, myricetin 3-O-rhamnopyranoside, myricetin, quercetin, quercetin-3-O-glucoside, as well as syringic acid, in regional chemical shifts of 10.0-6.0 ppm as aromatic compound area. The differences in spectral signal intensity revealed higher metabolite levels, specifically carbohydrates and amino acids, in red and purple fruits. However, green fruits had higher quantities of aromatic compounds.