Fruit quality, antioxidant, and mineral attributes of pomegranate cv. Ghojagh, influenced by shading and spray applications of potassium sulfate and sodium silicate.

Pomegranate (Punica granatum L.) fruit quality depends on many traits including visual, biochemical and mineral characteristics. One of the negative traits is aril whitening (AW) which is a frequently observed disorder in hot and dry climates, that leads to decline in desirable fruit quality. Color, antioxidant, and mineral contents of the arils are of prime importance as quality traits. Therefore, this study aims to investigate the effect of shading and foliar minerals on fruit quality during the fruit development stages of pomegranate. Treatments included shaded (50% green net) and unshaded trees and foliar application of trees with potassium sulfate (K, 1% and 2%) or sodium silicate (Si, 0.05, 0.1 and 0.15%) during two growing seasons. Results showed that the severity of AW at harvest decreased significantly when trees were covered with shading compared to control. The color values of L* and °hue for arils were lower in fruits grown under shading conditions indicating darker red arils. Shading significantly reduced chilling injury in cold storage compared to open field fruits. Shading and Si 0.15% increased superoxide dismutase, and catalase enzymes activity while decreased Polyphenol oxidase and peroxidase. Covering trees with shading and Si 0.15% spray resulted in the highest total anthocyanin, antioxidant activity, and total phenolics content in the arils. Shading as well as Si 0.15% increased macronutrients content of the arils. The study concluded that covering pomegranate trees and spraying with Si in hot climate reduced AW, increased antioxidant traits, and led to higher fruit quality.

Interacting effects of phytohormones and fruit pruning on the morpho-physiological and biochemical attributes of bell pepper.

Several factors, such as pruning and phytohormones, have demonstrated an influence on both the quantity and quality in the bell pepper. A factorial experiment using a completely randomized design was conducted on the Lumos yellow bell in a greenhouse. Treatments were the fruit pruning (0, 10, and 30%) and foliar application of phytohormones auxin (AUX) and gibberellic acid (GA3) at concentrations of 10 µM AUX, 10 µM GA3, 10 µM AUX + 10 µM GA3+, and 20 µM AUX + 10 µM GA3 along with controls. The plants were sprayed with phytohormones in four growth stages (1: flowering stage when 50% of the flowers were on the plant, 2: fruiting stage when 50% of the fruits were the size of peas, 3: fruit growth stage when 50% of the fruits had reached 50% of their growth, and 4: ripening stage when 50% of the fruits were at color break). The results of the present investigation showed that pruning rate of 30% yielded the highest flesh thickness and vitamin C content, decreased seed count and hastened fruit ripening. The use of GA3 along with AUX has been observed to augment diverse fruit quality characteristics. According to the results, the application of 10% pruning in combination with 20 µM AUX and 10 µM GA3 demonstrated the most significant levels of carotenoids, chlorophyll, and fruit length. The experimental group subjected to the combined treatment of 30% pruning and 10 µM AUX + 10 µM GA3 showed the most noteworthy levels of vitamin C, fruit weight, and fruit thickness. The groups that received the 10 µM GA3 and 20 µM AUX + 10 µM GA3 treatments exhibited the most favorable fruit flavor. According to the research results, the implementation of hormonal treatments 10 µM AUX and 10 µM AUX + 10 µM GA3 in combination with a 30% pruning strategy resulted in the most advantageous yield of bell peppers.

Integrative Analysis of Metabolome and Transcriptome of Carotenoid Biosynthesis Reveals the Mechanism of Fruit Color Change in Tomato (Solanum lycopersicum).

Tomato fruit ripening is accompanied by carotenoid accumulation and color changes. To elucidate the regulatory mechanisms underlying carotenoid synthesis during fruit ripening, a combined transcriptomic and metabolomic analysis was conducted on red-fruited tomato (WP190) and orange-fruited tomato (ZH108). A total of twenty-nine (29) different carotenoid compounds were identified in tomato fruits at six different stages. The abundance of the majority of the carotenoids was enhanced significantly with fruit ripening, with higher levels of lycopene; (E/Z)-lycopene; and α-, ß- and γ-carotenoids detected in the fruits of WP190 at 50 and 60 days post anthesis (DPA). Transcriptome analysis revealed that the fruits of two varieties exhibited the highest number of differentially expressed genes (DEGs) at 50 DPA, and a module of co-expressed genes related to the fruit carotenoid content was established by WGCNA. qRT-PCR analysis validated the transcriptome result with a significantly elevated transcript level of lycopene biosynthesis genes (including SlPSY2, SlZCIS, SlPDS, SlZDS and SlCRTSO2) observed in WP190 at 50 DPA in comparison to ZH108. In addition, during the ripening process, the expression of ethylene biosynthesis (SlACSs and SlACOs) and signaling (SlEIN3 and SlERF1) genes was also increased, and these mechanisms may regulate carotenoid accumulation and fruit ripening in tomato. Differential expression of several key genes in the fruit of two tomato varieties at different stages regulates the accumulation of carotenoids and leads to differences in color between the two varieties of tomato. The results of this study provide a comprehensive understanding of carotenoid accumulation and ethylene biosynthesis and signal transduction pathway regulatory mechanisms during tomato fruit development.

Involvement of the GH38 Family Exoglycosidase α-Mannosidase in Strawberry Fruit Ripening.

Exoglycosidase enzymes hydrolyze the N-glycosylations of cell wall enzymes, releasing N-glycans that act as signal molecules and promote fruit ripening. Vesicular exoglycosidase α-mannosidase enzymes of the GH38 family (EC 3.2.1.24; α-man) hydrolyze N-glycans in non-reduced termini. Strawberry fruit (Fragaria × ananassa) is characterized by rapid softening as a result of cell wall modifications during the fruit ripening process. Enzymes acting on cell wall polysaccharides explain the changes in fruit firmness, but α-man has not yet been described in F. × ananassa, meaning that the indirect effects of N-glycan removal on its fruit ripening process are unknown. The present study identified 10 GH38 α-man sequences in the F. × ananassa genome with characteristic conserved domains and key residues. A phylogenetic tree built with the neighbor-joining method and three groups of α-man established, of which group I was classified into three subgroups and group III contained only Poaceae spp. sequences. The real-time qPCR results demonstrated that FaMAN genes decreased during fruit ripening, a trend mirrored by the total enzyme activity from the white to ripe stages. The analysis of the promoter regions of these FaMAN genes was enriched with ripening and phytohormone response elements, and contained cis-regulatory elements related to stress responses to low temperature, drought, defense, and salt stress. This study discusses the relevance of α-man in fruit ripening and how it can be a useful target to prolong fruit shelf life.

Integrated Metabolomic-Transcriptomic Analyses of Flavonoid Accumulation in Citrus Fruit under Exogenous Melatonin Treatment.

The flavonoids in citrus fruits are crucial physiological regulators and natural bioactive products of high pharmaceutical value. Melatonin is a pleiotropic hormone that can regulate plant morphogenesis and stress resistance and alter the accumulation of flavonoids in these processes. However, the direct effect of melatonin on citrus flavonoids remains unclear. In this study, nontargeted metabolomics and transcriptomics were utilized to reveal how exogenous melatonin affects flavonoid biosynthesis in "Bingtangcheng" citrus fruits. The melatonin treatment at 0.1 mmol L-1 significantly increased the contents of seven polymethoxylated flavones (PMFs) and up-regulated a series of flavonoid pathway genes, including 4CL (4-coumaroyl CoA ligase), FNS (flavone synthase), and FHs (flavonoid hydroxylases). Meanwhile, CHS (chalcone synthase) was down-regulated, causing a decrease in the content of most flavonoid glycosides. Pearson correlation analysis obtained 21 transcription factors co-expressed with differentially accumulated flavonoids, among which the AP2/EREBP members were the most numerous. Additionally, circadian rhythm and photosynthesis pathways were enriched in the DEG (differentially expressed gene) analysis, suggesting that melatonin might also mediate changes in the flavonoid biosynthesis pathway by affecting the fruit's circadian rhythm. These results provide valuable information for further exploration of the molecular mechanisms through which melatonin regulates citrus fruit metabolism.

Genetic and Biotechnological Approaches to Improve Fruit Bioactive Content: A Focus on Eggplant and Tomato Anthocyanins.

Anthocyanins are a large group of water-soluble flavonoid pigments. These specialized metabolites are ubiquitous in the plant kingdom and play an essential role not only in plant reproduction and dispersal but also in responses to biotic and abiotic stresses. Anthocyanins are recognized as important health-promoting and chronic-disease-preventing components in the human diet. Therefore, interest in developing food crops with improved levels and compositions of these important nutraceuticals is growing. This review focuses on work conducted to elucidate the genetic control of the anthocyanin pathway and modulate anthocyanin content in eggplant (Solanum melongena L.) and tomato (Solanum lycopersicum L.), two solanaceous fruit vegetables of worldwide relevance. While anthocyanin levels in eggplant fruit have always been an important quality trait, anthocyanin-based, purple-fruited tomato cultivars are currently a novelty. As detailed in this review, this difference in the anthocyanin content of the cultivated germplasm has largely influenced genetic studies as well as breeding and transgenic approaches to improve the anthocyanin content/profile of these two important solanaceous crops. The information provided should be of help to researchers and breeders in devising strategies to address the increasing consumer demand for nutraceutical foods.

CmERF1 acts as a positive regulator of fruits and leaves growth in melon (Cucumis melo L.).

Melon (Cucumis melo L.) is an important horticultural and economic crop. ETHYLENE RESPONSE FACTOR1 (ERF1) plays an important role in regulating plant development, and the resistance to multiple biotic and abiotic stresses. In this study, developmental biology, molecular biology and biochemical assays were performed to explore the biological function of CmERF1 in melon. Abundant transcripts of CmERF1 were found in ovary at green-yellow bud (GYB) and rapid enlargement (ORE) stages. In CmERF1 promoter, the cis-regulatory elements for indoleacetic acid (IAA), methyl jasmonate (MeJA), salicylic acid (SA), abscisic acid (ABA), gibberellic acid (GA), light and low temperature responses were found. CmERF1 could be significantly induced by ethylene, IAA, MeJA, SA, ABA, and respond to continuous light and low temperature stresses in melon. Ectopic expression of CmERF1 increased the length of siliqua and carpopodium, and expanded the size of leaves in Arabidopsis. Knockdown of CmERF1 led to smaller ovary at anthesis, mature fruit and leaves in melon. In CmERF1-RNAi #2 plants, 75 genes were differently expressed compared with control, and the promoter regions of 28 differential expression genes (DEGs) contained the GCC-box (AGCCGCC) or DRE (A/GCCGAC) cis-acting elements of CmERF1. A homolog of cell division cycle protein 48 (CmCDC48) was proved to be the direct target of CmERF1 by the yeast one-hybrid assay and dual-luciferase (LUC) reporter (DLR) system. These results indicated that CmERF1 was able to promote the growth of fruits and leaves, and involved in multiple hormones and environmental signaling pathways in melon.

Transcriptome and metabolome analysis revealed the dynamic change of bioactive compounds of Fructus Ligustri Lucidi.

BACKGROUND: The Fructus Ligustri Lucidi, the fruit of Ligustrum lucidum, contains a variety of bioactive compounds, such as flavonoids, triterpenoids, and secoiridoids. The proportions of these compounds vary greatly during the different fruit development periods of Fructus Ligustri Lucidi. However, a clear understanding of how the proportions of the compounds and their regulatory biosynthetic mechanisms change across the different fruit development periods of Fructus Ligustri Lucidi is still lacking. RESULTS: In this study, metabolite profiling and transcriptome analysis of six fruit development periods (45 DAF, 75 DAF, 112 DAF, 135 DAF, 170 DAF, and 195 DAF) were performed. Seventy compounds were tentatively identified, of which secoiridoids were the most abundant. Eleven identified compounds were quantified by high performance liquid chromatography. A total of 103,058 unigenes were obtained from six periods of Fructus Ligustri Lucidi. Furthermore, candidate genes involved in triterpenoids, phenylethanols, and oleoside-type secoiridoid biosynthesis were identified and analyzed. The in vitro enzyme activities of nine glycosyltransferases involved in salidroside biosynthesis revealed that they can catalyze trysol and hydroxytyrosol to salidroside and hydroxylsalidroside. CONCLUSIONS: These results provide valuable information to clarify the profile and molecular regulatory mechanisms of metabolite biosynthesis, and also in optimizing the harvest time of this fruit.

Plastid-expressed AdDjSKI enhances photosystem II stability, delays leaf senescence, and increases fruit yield in tomato plants under heat stress.

Heat stress substantially reduces tomato (Solanum lycopersicum) growth and yield globally, thereby jeopardizing food security. DnaJ proteins, constituents of the heat shock protein system, protect cells from diverse environmental stresses as HSP-70 molecular co-chaperones. In this study, we demonstrated that AdDjSKI, a serine-rich DnaJ III protein induced by pathogens, plays an important role in stabilizing photosystem II (PSII) in response to heat stress. Our results revealed that transplastomic tomato plants expressing the AdDjSKI gene exhibited increased levels of total soluble proteins, improved growth and chlorophyll content, reduced malondialdehyde (MDA) accumulation, and diminished PSII photoinhibition under elevated temperatures when compared with wild-type (WT) plants. Intriguingly, these transplastomic plants maintained higher levels of D1 protein under elevated temperatures compared with the WT plants, suggesting that overexpression of AdDjSKI in plastids is crucial for PSII protection, likely due to its chaperone activity. Furthermore, the transplastomic plants displayed lower accumulation of superoxide radical (O2 •─) and H2O2, in comparison with the WT plants, plausibly attributed to higher superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. This also coincides with an enhanced expression of corresponding genes, including SlCuZnSOD, SlFeSOD, SlAPX2, and SltAPX, under heat stress. Taken together, our findings reveal that chloroplastic expression of AdDjSKI in tomatoes plays a critical role in fruit yield, primarily through a combination of delayed senescence and stabilizing PSII under heat stress.

Low oxygen environment effect on the tomato cell wall composition during the fruit ripening process.

BACKGROUND: Oxygen concentration is a key characteristic of the fruit storage environment determining shelf life and fruit quality. The aim of the work was to identify cell wall components that are related to the response to low oxygen conditions in fruit and to determine the effects of such conditions on the ripening process. Tomato (Solanum lycopersicum) fruits at different stages of the ripening process were stored in an anoxic and hypoxic environment, at 0% and 5% oxygen concentrations, respectively. We used comprehensive and comparative methods: from microscopic immunolabelling and estimation of enzymatic activities to detailed molecular approaches. Changes in the composition of extensin, arabinogalactan proteins, rhamnogalacturonan-I, low methyl-esterified homogalacturonan, and high methyl-esterified homogalacturonan were analysed. RESULTS: In-depth molecular analyses showed that low oxygen stress affected the cell wall composition, i.e. changes in protein content, a significantly modified in situ distribution of low methyl-esterified homogalacturonan, appearance of callose deposits, disturbed native activities of ß-1,3-glucanase, endo-ß-1,4-glucanase, and guaiacol peroxidase (GPX), and disruptions in molecular parameters of single cell wall components. Taken together, the data obtained indicate that less significant changes were observed in fruit in the breaker stage than in the case of the red ripe stage. The first symptoms of changes were noted after 24 h, but only after 72 h, more crucial deviations were visible. The 5% oxygen concentration slows down the ripening process and 0% oxygen accelerates the changes taking place during ripening. CONCLUSIONS: The observed molecular reset occurring in tomato cell walls in hypoxic and anoxic conditions seems to be a result of regulatory and protective mechanisms modulating ripening processes.

Modulation of secondary metabolism and redox regulation by exogenously applied glutathione improves the shelf life of Capsicum annuum L. fruit.

Role of redox homeostasis in fruit ripening of Capsicum annuum L. with oxidative metabolism was studied. The research aims the ability to reduce agents during postharvest storage on fruit for delayed ripening with the regulation of oxidative stress. Thus, we applied 10 mM reduced glutathione (GSH) to fruit as pretreatment followed by 1 mM hydrogen peroxide (H2O2) as ripening-inducing treatment and observed during 7 days of storage at 25 °C. A decrease in total soluble solid and firmness under H2O2, was increased while dehydration in tissue was decreased by GSH pretreatment. Glutathione regulated the turnover of organic acids to reducing sugars with higher activity of NADP malic enzyme that sustained the fruit coat photosynthesis through chlorophyll fluorescence, pigment composition, and photosystem II activity. Malondialdehyde accumulation was inversely correlated with GSH content and antioxidative enzyme activity that reduced loss of cell viability. Conclusively, regulation of oxidative stress with GSH may be effective in the extension of shelf life under postharvest storage.

RNA-seq-based transcriptome profiling of early fruit development in Chieh-qua and analysis of related transcription factors.

Chieh-qua (Benincasa hispida Cogn. var. Chieh-qua How.) fruit development starts post pollination. With the continuous expansion of the fruit, the soluble solid content of the fruit decreases. Because there are no reports on the early development of Chieh-qua fruit, this study compared fruit transcriptomes at 0-, 3-, and 7 day post pollination (dpp). 104,747 unigenes were assembled from clean reads and compared using six public databases for similarity searching. Compared with those of 0 dpp (C), there were differences in the expression of 12,982 and 6541 genes in the fruit tissue at 3 dpp and 7 dpp, respectively. Compared with 3 dpp (B), there were 14,314 differentially expressed genes in the fruit at 7 dpp (A). Based on the analysis of transcription factors, 213 nucleotides in the MYB superfamily were identified; among them, 94 unigenes of the MYB superfamily were differentially expressed at the three stages. In the pairwise comparison of differential expression, eight unigenes (Gene_id: TRINITY_DN32880_c1_g2, TRINITY_DN35142_c2_g2, TRINITY_DN32454_c11_g6, TRINITY_DN34105_c2_g7, TRINITY_DN32758_c3_g3, TRINITY_DN33604_c4_g10, TRINITY_DN34466_c3_g1, TRINITY_DN35924_c3_g2) were homologous to those of MYB59, MYB-GT3b, MYB18, MYB4, MYB108, MYB306, MYB340, and MYB-bHLH13. These unigenes differed significantly among the three stages. Furthermore, MYB59 and MYB18 exhibited higher expression at 7 dpp. MYB4, MYB-GT3b, MYB108, and MYB306 showed the highest expression levels in fruits at 3 dpp. In addition, MYB340 and MYB-bHLH13 showed higher expression levels during the unpollinated stage. MYB59, MYB-GT3b, MYB18, MYB4, MYB108, MYB306, MYB340, and MYB-bHLH13 may play crucial roles in Chieh-qua fruit development, defense, and blossoming. This study provides a basis for further investigation of MYB superfamily genes involved in early fruit expansion in chieh-qua.

Screening and verification of proteins that interact with the anthocyanin-related transcription factor PbrMYB114 in 'Yuluxiang' pear.

Despite extensive research highlighting the pivotal role of MYB transcription factors in regulating anthocyanin biosynthesis, the interactive regulatory network involving these MYB factors in pear fruits remains inadequately characterized. In this study, the anthocyanin-regulatory gene PbrMYB114 was successfully cloned from 'Yuluxiang' pear (Pyrus bretschneideri) fruits, and its influence on anthocyanin accumulation was confirmed through transient expression assays. Specifically, the co-transformation of PbrMYB114 with its partner PbrbHLH3 in pears served to validate the functional role of PbrMYB114. Subsequently, PbrMYB114 was employed as bait in a yeast two-hybrid screening assay, using a 'Yuluxiang' pear protein library, which led to the identification of 25 interacting proteins. Further validation of the interactions between PbrMYB114 and PbrMT2/PbrMT3 was conducted. Investigations into the role of PbrMT2 and PbrMT3 in 'Duli' seedlings (Pyrus betulaefolia) revealed their potential to enhance anthocyanin accumulation. The outcomes of these studies provide novel insights into the protein network that regulates pear anthocyanin biosynthesis, particularly the functional interactions among PbrMYB114 and associated proteins.

Physicochemical and Volatile Compounds Analysis of Fruit Wines Fermented with Saccharomyces cerevisiae: FTIR and Microscopy Study with Focus on Anti-Inflammatory Potential.

The growing trend in fruit wine production reflects consumers' interest in novel, diverse drinking experiences and the increasing demand for healthier beverage options. Fruit wines made from kiwi, pomegranates, and persimmons fermented using S. bayanus Lalvin strain EC1118 demonstrate the versatility of winemaking techniques. Kiwifruit, persimmon, and pomegranate wines were analyzed using HPLC and GC-TOFMS analyses to determine their concentrations of phenolic acids and volatile compounds. These results were supported by Fourier transform infrared (FTIR) spectroscopy to characterize and compare chemical shifts in the polyphenol regions of these wines. The wines' characterization included an anti-inflammatory assay based on NO, TNF-alpha, and IL-6 production in the RAW 264.7 macrophage model. FTIR spectroscopy predicted the antioxidant and phenolic contents in the wines. In terms of polyphenols, predominantly represented by chlorogenic, caffeic, and gallic acids, pomegranate and kiwifruit wines showed greater benefits. However, kiwifruit wines exhibited a highly diverse profile of volatile compounds. Further analysis is necessary, particularly regarding the use of other microorganisms in the fermentation process and non-Saccharomyces strains methods. These wines exhibit high biological antioxidant potential and health properties, providing valuable insights for future endeavors focused on designing healthy functional food products.

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.

Application of Synephrine to Grape Increases Anthocyanin via Production of Hydrogen Peroxide, Not Phytohormones.

Global warming has caused such problems as the poor coloration of grape skin and the decreased production of high-quality berries. We investigated the effect of synephrine (Syn) on anthocyanin accumulation. Anthocyanin accumulation in cultured grape cells treated with Syn at concentrations of 1 mM or higher showed no significant difference, indicating that the accumulation was concentration-independent. On the other hand, anthocyanin accumulation was dependent on the compound used for treatment. The sugar/acid ratio of the juice from berries treated with Syn did not differ from the control. The expression of anthocyanin-biosynthesis-related genes, but not phytohormones, was increased by the treatment with Syn at 24 h or later. The Syn treatment of cultured cells increased SOD3 expression and hydrogen peroxide (H2O2) production from 3 to 24 h after treatment. Subsequently, the expression of CAT and APX6 encoding H2O2-scavenging enzymes was also increased. Treatment of cultured cells with Syn and H2O2 increased the expression of the H2O2-responsive gene Chit4 and the anthocyanin-biosynthesis-related genes mybA1 and UFGT 4 days after the treatment and increased anthocyanin accumulation 7 days after the treatment. On the other hand, the treatment of berries with Syn and H2O2 increased anthocyanin accumulation after 9 days. These results suggest that Syn increases anthocyanin accumulation through H2O2 production without changing phytohormone biosynthesis. Syn is expected to improve grape skin coloration and contribute to high-quality berry production.

Effects of extra potassium supply and rootstocks indicate links between water, solutes and energy in Shiraz grapevines (Vitis vinifera) pericarps.

Potassium (K) is essential for the development of grapevines (Vitis vinifera ), accumulating into berries during maturation. Elevated K has been associated with high sugar and low acidity in juice. Characterising the accumulation patterns of K and other components in pericarps treated with various experimental factors may indicate potential regulators of berry K levels. A soil fertiliser trial using nutrient solutions with two K supply rates was conducted on potted Shiraz vines during berry ripening. Doubled-K supply increased L-malic acid content in the early-ripening phase, and increased K and magnesium concentrations in the late-ripening phase. Doubled-K supply reduced the ratio of K to sodium in later ripening phases, suggesting that the accumulation of K relative to sodium was limited in more mature berries supplied with extra K. Pericarp water percentage, sugar, K and ATP were correlated in both treatments, indicating links between hydration, solute transport and energy in maturing berries. In a separate rootstock trial over the two growing seasons, Shiraz scions grafted onto 420-A rootstock produced berries with lower K concentration and content than those grafted onto Ramsey or Ruggeri-140 rootstocks and own-rooted vines. This study demonstrated that the K supply and berry ripening phase impacted the berry K level.

Mitigation of drought stress in chili plants (Capsicum annuum L.) using mango fruit waste biochar, fulvic acid and cobalt.

Drought stress can have negative impacts on crop productivity. It triggers the accumulation of reactive oxygen species, which causes oxidative stress. Limited water and nutrient uptake under drought stress also decreases plant growth. Using cobalt and fulvic acid with biochar in such scenarios can effectively promote plant growth. Cobalt (Co) is a component of various enzymes and co-enzymes. It can increase the concentration of flavonoids, total phenols, antioxidant enzymes (peroxidase, catalase, and polyphenol oxidase) and proline. Fulvic acid (FA), a constituent of soil organic matter, increases the accessibility of nutrients to plants. Biochar (BC) can enhance soil moisture retention, nutrient uptake, and plant productivity during drought stress. That's why the current study explored the influence of Co, FA and BC on chili plants under drought stress. This study involved 8 treatments, i.e., control, 4 g/L fulvic acid (4FA), 20 mg/L cobalt sulfate (20CoSO4), 4FA + 20CoSO4, 0.50%MFWBC (0.50 MFWBC), 4FA + 0.50MFWBC, 20CoSO4 + 0.50MFWBC, 4FA + 20CoSO4 + 0.50MFWBC. Results showed that 4 g/L FA + 20CoSO4 with 0.50MFWBC caused an increase in chili plant height (23.29%), plant dry weight (28.85%), fruit length (20.17%), fruit girth (21.41%) and fruit yield (25.13%) compared to control. The effectiveness of 4 g/L FA + 20CoSO4 with 0.50MFWBC was also confirmed by a significant increase in total chlorophyll contents, as well as nitrogen (N), phosphorus (P), and potassium (K) in leaves over control. In conclusion4g/L, FA + 20CoSO4 with 0.50MFWBC can potentially improve the growth of chili cultivated in drought stress. It is suggested that 4 g/L FA + 20CoSO4 with 0.50MFWBC be used to alleviate drought stress in chili plants.

Effect of SlSAHH2 on metabolites in over-expressed and wild-type tomato fruit.

Background: Tomato (Solanum lycopersicum) is an annual or perennial herb that occupies an important position in daily agricultural production. It is an essential food crop for humans and its ripening process is regulated by a number of genes. S-adenosyl-l-homocysteine hydrolase (AdoHcyase, EC 3.3.1.1) is widespread in organisms and plays an important role in regulating biological methylation reactions. Previous studies have revealed that transgenic tomato that over-express SlSAHH2 ripen earlier than the wild-type (WT). However, the differences in metabolites and the mechanisms driving how these differences affect the ripening cycle are unclear. Objective: To investigate the effects of SlSAHH2 on metabolites in over-expressed tomato and WT tomato. Methods: SlSAHH2 over-expressed tomato fruit (OE-5# and OE-6#) and WT tomato fruit at the breaker stage (Br) were selected for non-targeted metabolome analysis. Results: A total of 733 metabolites were identified by mass spectrometry using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the Human Metabolome database (HMDB). The metabolites were divided into 12 categories based on the superclass results and a comparison with the HMDB. The differences between the two databases were analyzed by PLS-DA. Based on a variable important in projection value >1 and P < 0.05, 103 differential metabolites were found between tomato variety OE-5# and WT and 63 differential metabolites were found between OE-6# and WT. These included dehydrotomatine, L-serine, and gallic acid amongst others. Many metabolites are associated with fruit ripening and eight common metabolites were found between the OE-5# vs. WT and OE-6# vs. WT comparison groups. The low L-tryptophan expression in OE-5# and OE-6# is consistent with previous reports that its content decreases with fruit ripening. A KEGG pathway enrichment analysis of the significantly different metabolites revealed that in the OE-5# and WT groups, up-regulated metabolites were enriched in 23 metabolic pathways and down-regulated metabolites were enriched in 11 metabolic pathways. In the OE-6# and WT groups, up-regulated metabolites were enriched in 29 pathways and down-regulated metabolites were enriched in six metabolic pathways. In addition, the differential metabolite changes in the L-serine to flavonoid transformation metabolic pathway also provide evidence that there is a phenotypic explanation for the changes in transgenic tomato. Discussion: The metabolomic mechanism controlling SlSAHH2 promotion of tomato fruit ripening has been further elucidated.

SlZIP11 mediates zinc accumulation and sugar storage in tomato fruits.

Background: Zinc (Zn) is a vital micronutrient essential for plant growth and development. Transporter proteins of the ZRT/IRT-like protein (ZIP) family play crucial roles in maintaining Zn homeostasis. Although the acquisition, translocation, and intracellular transport of Zn are well understood in plant roots and leaves, the genes that regulate these pathways in fruits remain largely unexplored. In this study, we aimed to investigate the function of SlZIP11 in regulating tomato fruit development. Methods: We used Solanum lycopersicum L. 'Micro-Tom' SlZIP11 (Solanum lycopersicum) is highly expressed in tomato fruit, particularly in mature green (MG) stages. For obtaining results, we employed reverse transcription-quantitative polymerase chain reaction (RT-qPCR), yeast two-hybrid assay, bimolecular fluorescent complementation, subcellular localization assay, virus-induced gene silencing (VIGS), SlZIP11 overexpression, determination of Zn content, sugar extraction and content determination, and statistical analysis. Results: RT-qPCR analysis showed elevated SlZIP11 expression in MG tomato fruits. SlZIP11 expression was inhibited and induced by Zn deficiency and toxicity treatments, respectively. Silencing SlZIP11 via the VIGS technology resulted in a significant increase in the Zn content of tomato fruits. In contrast, overexpression of SlZIP11 led to reduced Zn content in MG fruits. Moreover, both silencing and overexpression of SlZIP11 caused alterations in the fructose and glucose contents of tomato fruits. Additionally, SlSWEEET7a interacted with SlZIP11. The heterodimerization between SlSWEET7a and SlZIP11 affected subcellular targeting, thereby increasing the amount of intracellularly localized oligomeric complexes. Overall, this study elucidates the role of SlZIP11 in mediating Zn accumulation and sugar transport during tomato fruit ripening. These findings underscore the significance of SlZIP11 in regulating Zn levels and sugar content, providing insights into its potential implications for plant physiology and agricultural practices.