Stages Of Berry Development Research Articles

Brassinosteroids enhance the tolerance, production, and fruit quality of covered table grape vines

ABSTRACT Plastic covering (PC) is used to speed up the ripening and harvesting of grapes while also shielding grapevines from unfavourable climatic conditions. This study aimed to determine how PC induced abiotic stress on covered vines and assess the role of brassinosteroids (Brs) in alleviating these impacts. The results showed that PC caused a substantial rise in soluble sugar, MDA, proline, total phenol, and antioxidant enzymes (catalase and ascorbate peroxidase) and decreased insoluble sugars and carbohydrates in ‘Superior' seedless grape leaves. Applying Brs at concentrations of 0, 1, 2, and 3 mg/l twice during the berry development stages (pea and veraison) enhanced the plants’ ability to withstand PC-induced stress. The concentration of 3 mg/l Brs elevated some metabolic activities, including insoluble sugar, total carbohydrates, proline, and total phenol. Additionally, it increased the antioxidant enzyme activity. Meanwhile, 2 mg/l appeared to be the most effective concentration in achieving the highest cluster and berry weight, enhanced total soluble solids (TSS) and firmness, and reduced weight loss over shelf life. In conclusion, applying Brs could be a promising strategy to alleviate the adverse effect of abiotic stress on table grapes.

Identification and Validation of New Reference Genes for Normalization of Gene Expression in Flower and Berry Developmental Stages of Interspecific Grape Hybrid V. vinifera (L.) × V. labrusca (L.)

Abstract In quantitative reverse transcription polymerase chain reaction (qRT-PCR), normalizing target gene expression using a reference gene is an indispensable step to control the variability of RNA extraction yield, RNA integrity, reverse transcription efficiency, and PCR amplification. In the present study, we identified candidate reference genes with stable expression during grapes’ flowering and berry development stages. Ten genes, including ACT, CYP5, RLI, TUB, UBC, UBC17, UBC60, UFD1, VAG, and ZNF with relatively stable expression, were selected based on RNAseq data generated earlier in grape hybrid ‘ARI 516’. The expression of these candidate genes was tested at different stages of flowering and grape berry development. Five different algorithms such as RefFinder, geNorm, NormFinder, BestKeeper, and the comparative ΔCq method were used to test the expression stability of candidate genes. A comprehensive ranking obtained by RefFinder showed that UBC17, RLI, and ZNF were the most stable reference genes during flower and berry development stages. UBC17, RLI, and ZNF were calibrators to normalize the expression of VvAGL11 as a target gene to validate the worthiness of identified reference genes. The result demonstrated that newly identified reference genes could be successfully used to normalize the expression of the target gene accurately. These reference genes will provide more choices for selecting appropriate reference genes to normalize gene expression in grapes.

Yield and Fruit Characteristics of Tomato Crops Grown with Mineral Macronutrients: Impact of Organo-Mineral Fertilizers through Foliar or Soil Applications.

The utilization of plant biostimulants has gained importance as a strategy by which to improve plant productivity and soil health. Two independent trials were conducted across two seasons (2021 and 2023) to evaluate the effects of foliar or soil applications of various commercial organo-mineral fertilizers (Futuroot®, Radicon® Amifort®) with biostimulant action that is exerted on yield and fruit characteristics of processing tomato crops (cv Taylor F1) that have been exposed to mineral macronutrients. These treatments were administered three times during the season: at the transplanting, pre-flowering and berry development stages. In the first trial, conducted in two fields characterized respectively by low and high fertility, foliar applications of Radicon®, which is based on humic acid and amino acids, increased the leaf greenness index SPAD compared with the control. Furthermore, the leaf green colour intensity (SPAD index), measured during the reproductive phases of the tomato exhibited a positive correlation (R2 = 0.726) with the marketable yield obtained. This increase in marketable yield was significant in the biostimulant treatment compared with the control in both soils, especially in the soil characterized by lower fertility (16.1%), when compared with the more fertile soil (6.8%). In the second trial, conducted in the low-fertility field mentioned above, soil applications of all biostimulants (Futuroot®, Radicon® and the combinations [Radicon® + Amifort-Plus®]) significantly increased the marketable yield by 27.8%, 13.5% and 27.7%, respectively, compared with the control. The most significant beneficial effects of both Futuroot® and [Radicon® + Amifort®] could be attributed to the combination of humic acids and auxins, cytokinins or microelements (Zn, Mn, MgO) present in the formulation of these products. Furthermore, the increase in marketable yield obtained when Radicon® was applied to leaves was higher (16.1%) than that observed with soil application (13.5%). In both trials, no relevant effects of biostimulant products were observed on most of the physicochemical characteristics of tomato fruits. In conclusion, the biostimulants based on humic acid and amino acids combined with chemical fertilizers tested in the present study and applied by fertigation were more effective in improving tomato yield, and therefore they can be recommended for efficient agricultural production.

Unveiling the transformations in phytochemicals and grape features: a thorough examination of 'Italia' and 'Bronx Seedless' cultivars throughout multiple berry development stages

Understanding the physical and phytochemical characteristics of grape cultivars across different berry development stages is crucial for optimizing grape production and quality in the agricultural and viticultural industries. The study, therefore, investigated the physical characteristics and phytochemical composition of 'Italia' and 'Bronx Seedless' grape cultivars harvested across six distinct periods. In grape cultivars displayed an intriguing journey in terms of resveratrol, ranging from 5.96 mg/kg in Period I to 11.59 mg/kg in Period VI. These vital compounds known for contributing to grape color and potential health benefits showed substantial variation across the grape cultivars and harvest periods. In addition, significant variations in phytochemical compositions were observed between 'Italia' and 'Bronx Seedless' grape cultivars, with 'Italia' generally exhibiting higher concentrations of key compounds such as resveratrol, pterostilbene, anthocyanidins, and flavonoids. The longitudinal analysis across six berry developmental periods highlighted a progressive increase in the concentrations of these phytochemicals in cultivar, indicating a dynamic evolution of grape biochemistry over time. Particularly, delphinidin-3-O-glycoside, cyanidin-3-O-glycoside, and petunidin-3-O-glycoside showed marked increases, indicating significant growth in anthocyanin content from Period I to Period VI. Utilizing PCA biplots and a hierarchical clustering heatmap, the study visually represented the relationships and variances among various phytochemical components. The insights revealed how certain compounds clustered together, suggesting similarities and dissimilarities. The positioning of compounds on these plots indicated their significance in characterizing grape cultivars and their maturation over time. In summary, the data underlined the strong influence of berry development time on phytochemical composition, emphasizing the importance of strategic grape harvesting to attain desired phytochemical profiles for wine or other grape products. The findings provide valuable insights for grape growers, winemakers, and researchers aiming to exploit the full potential of these compounds in grape-based products and for those interested in understanding the dynamics of grape phytochemistry.

Effect of PGR and Chemicals on Shelf Life, Bunch and Berry Quality Parameters of Sudhakar Seedless Grapes (Vitis vinifera L.)

The experiment was conducted on Sudhakar Seedless vines grafted on 110-R rootstock were selected for this study. The experiment was designed in randomized block design (RBD) having five treatments with four replications were carried out at MRDBS Nashik during 2020-2021. Pre-harvest application of treatments (Chitosan at 10 ppm, Naphthalene acetic acid at 100 ppm, activated Potassium salt @ 2.0 g/ liter, Salicylic acid at 2.0 ml/liter and Potassium Schoenite @ 2.0 g/liter along with untreated vines were applied at veraison stage of berry development. Application of Chitosan @ 10 ppm resulted in to the increase berry size and berry quality along with less Number of rotten berries in physiological loss in weight. Followed by the application of Naphthalene acetic acid at 100 ppm recorded less Number of rotten in this study. However, the lowest physiological loss of weight (%) were recorded with the application of Naphthalene acetic acid. The increasing dose of Naphthalene acetic acid resulted into decrease in pre- harvest berry drop. In grapevines, Application of salicylic acid significantly increase in berry weight, bunch weight, Total Soluble Solids /acidity ratio as compare to untreated vines. Biochemical composition of berries was influenced by the application of Activated potassium salt at different concentration. The application of Potassium schoenite in grapevines were found effective for increasing TSS of Sudhakar seedless grapes.

Comparative transcriptome profiling of fruit tissue provides novel insights into piperine biosynthesis in black pepper (Piper nigrum L.)

Black pepper (Piper nigrum L.) is a storehouse of numerous bioactive compounds, most important being the alkaloid piperine. This metabolite has immense applications in both food and pharmaceutical industries. Therefore, studying the pathways involved in piperine biosynthesis is of paramount importance for improving the piperine content in black pepper. In the present study, we have estimated the piperine content across different fruit/berry developmental stages (DS1 to DS8) and leaf tissue of two different traditional landraces of black pepper, using the high-performance liquid chromatography (HPLC) method. Based on the results obtained, the landrace Thottumuriyan was identified to possess higher piperine content amongst the two landraces with high piperine content detected at the mid-developmental stages. The fruit tissues spanning the different developmental stages (DS2, DS4, DS6 and DS8) were selected for comparative transcriptome profiling. An average of 150 million read pairs were generated for the five different samples (4 berry development stages and the leaf tissue). These were mapped against the black pepper reference genome and differentially expressed genes (DEGs) were identified for the four different combinations. Further transcript profiling of twenty candidate genes potentially involved in secondary metabolite biosynthesis pathways, including piperine synthesis, was performed using Real time PCR in the eight different berry developmental stages. Highest expression for the genes associated with piperine biosynthesis was observed at mid-developmental stages. This included the genes coding for piperine synthase and piperic acid-CoA ligase. Our data provides critical information to understand the molecular mechanisms underlying piperine biosynthesis and other pathways in black pepper.

Methylation-related alternative splicing events in H2O2-treated Kyoho grape berries during development

Hydrogen peroxide, methylation and alternative splicing (AS) all play important roles in fruit development, but the regulatory relationship between them in fruit development is unclear. In this study, AS events occurring at different developmental stages of the H2O2 treated and control berries of Kyoho from 35 to 65 days post anthesis were analyzed based on RNA-seq data. The results showed that alternative 3′ splice site (A3) was the most type and mutually exclusive exons (MX) was the least type revealed in both the treatment and control. There was stage-specific regulation of AS during grape berries development and the events of AS were more abundant at the early stages of berry development, and 11,670 was identified as the conserved events during berry development. There were 657 AS events which showed significant differences between the treatment and control, and functional annotation demonstrated that 10 of these genes were associated with methylation modifications. The significant differences in the extent of AS of these methylation related genes in the treatment and control suggest that AS, methylation modification and H2O2 synergistically regulate the grape berries ripening process.

Effects of Water Stress on Resveratrol Accumulation and Synthesis in ‘Cabernet Sauvignon’ Grape Berries

Resveratrol (3, 4′, 5 trihydroxy stilbene) is a natural phytoalexin produced by plants in response to biotic and abiotic stresses. It is well known for its cardio-protective, anticarcinogenic, and antioxidant properties. This study characterized physiological and molecular changes in resveratrol synthesis exposed to two levels of water stress at distinct grape berry developmental stages. Physiological data were measured to assess the berry quality. We used high-performance liquid chromatography to study enzyme activity and qRT-PCR to assess the expression levels of genes involved in resveratrol synthesis. The berry development was suppressed under water stress, while the content of total polyphenol, especially resveratrol was enhanced. Related enzymes and genes regulate the changes in resveratrol in plants. Water stress improved the enzyme activities of PAL (phenylalanine ammonia-lyase) and STS (stilbene synthase) after veraison. Moreover, the transcription factors VvMYB14, VvMYB15 and resveratrol synthesis-related genes are also changed. Expression of Vv4CL and VvMYB15 were upregulated during the pre-reversion stage, whereas VvPAL and VvSTS increased throughout development. As the co-substrate of VvSTS, VvCHS decreased during the berry development. Our study demonstrates that water stress regulates resveratrol synthesis through enzymatic activities and the gene expression of PAL and STS.

VvPL11 Is a Key Member of the Pectin Lyase Gene Family Involved in Grape Softening

Fruit ripening includes several metabolic changes that lead to sweeter and softer fruit. Pectin depolymerization is one of major factors that softens developing grape berries. Pectin lyases (PLs) play important roles in pectin degradation in the grape berry. However, little is known about the temporal and spatial expression of grapevine (Vitis spp.) pectin lyase genes (VvPLs) or their function during fruit ripening and softening. In this study, 18 individual VvPL genes were identified in the grape genome. All VvPL genes were sorted into group I and group II, except VvPL12 which demonstrated higher and similar expression trends in different tissues and organs. In grape berry, VvPL1, 5, 7, 11 and 16 were highly expressed, whereas VvPL18, 15, 2, 13, 10, 14, 17, 6 and 8 showed lower expression levels at different berry developmental stages. Expression of VvPL11 firstly increased and then decreased, and the highest expression was shown at 6 weeks after full bloom (WAFB) during berry development. Over-expression of the VvPL11 gene in tomato caused higher ethylene production and lower firmness compared to wild-type fruit. Moreover, decreased propectin and increased water-soluble pectin (WSP) levels were observed in VvPL11 transgenic tomato fruit. Consistent with this result, the expression levels of SlPG2, SlEXP, and SlPME1, all of which are genes involved in fruit softening, were up-regulated in VvPL11-OE tomato fruit, which supported the idea that VvPL11 plays an important role in fruit ripening and softening. This study provided a comprehensive analysis of the grapevine PL family and advanced our knowledge of the functions of VvPLs during fruit softening.

The influence of light microclimate on the lipid profile and associated transcripts of photosynthetically active grape berry seeds.

Lipids and oils determine the quality and industrial value of grape seeds. Studies with legume seeds demonstrated the influence of light on lipid metabolism and its association with seed photosynthesis. Grape berry seeds are photosynthetically active till mature stage, but mostly during the green stage and veraison. The objective of this work was to compare the lipid profiles of seeds from white grape berries (cv. Alvarinho) growing at two contrasting light microclimates in the canopy (low and high light, LL and HL respectively), previously reported to have distinct photosynthetic competences. Berries were collected at three developmental stages (green, veraison and mature) and from both microclimates, and the seeds were analyzed for their lipid profiles in an untargeted manner using liquid chromatography coupled to high resolution mass spectrometry (LCMS). The seed lipid profiles differed greatly among berry developmental stages, and to a lesser extend between microclimates. The LL microclimate coincided with a higher relative levels of fatty acids specifically at mature stage, while the HL microclimate led to an up-regulation of ceramides at green stage and of triacylglycerols and glycerophospholipids at mature stage. The seed transcript levels of four key genes (VvACCase1, VvΔ9FAD, VvFAD6 and VvLOXO) involved in fatty acid metabolism were analyzed using real-time qPCR. The lipoxygenase gene (VvLOXO) was down- and up-regulated by HL, as compared to LL, in seeds at green and veraison stages, respectively. These results suggest that seed photosynthesis may play distinct roles during seed growth and development, possibly by fueling different lipid pathways: at green stage mainly towards the accumulation of membrane-bound lipid species that are essential for cell growth and maintenance of the photosynthetic machinery itself; and at veraison and mature stages mainly towards storage lipids that contribute to the final quality of the grape seeds.

Diversity Analysis of Culturable Epiphytic Microbial Consortia of Table Grape Berry Surface

ABSTRACT The health and yield of grapes are affected by the microorganisms associated with the grapevine. The diversity of microorganisms present on the wine grape varieties is well defined whereas, the information associated with the microorganisms of table grape varieties remains scarce. In the present study, culture-dependent method was used to isolate the microbes present on the surface of the commercial white seedless table grape cultivar, Thompson Seedless at different stages of berry development. The microbial load of the grape berry surface increased as the berry progressed toward the ripening stage resulting in the identification of core bacteria (29), filamentous fungi (19) and yeast (3). A diversity analysis study also revealed that Cladosporium cladosporioides, was found in the vineyard on grapes from the early berry development stages, as an emerging pre-harvest pathogen. The study would help in understanding and exploiting the microbiota of table grape berry in agronomic and biotechnological applications.

Severe Shoot Trimming and Crop Size as Tools to Modulate Cv. Merlot Berry Composition.

Viticulture production is challenged by climate change and the consequent higher accumulation of carbohydrates in grapevine berries, resulting in high-alcoholic wines. This study investigates the application of severe shoot trimming performed at three different stages and crop size management as tools for the modulation of cv. Merlot berry composition, aimed at reducing the sugar content in the berry. In the first study, the effects of severe shoot trimming carried out at three different phenological stages were studied. In the second study, late severe shoot trimming was combined with two crop sizes and regulated by shoot thinning. The obtained results demonstrated that severe shoot trimming in earlier stages of berry development limited the accumulation of both sugars and anthocyanins as compared to the control treatment. However, when severe shoot trimming was performed at late veraison (at approximately 14 Brix), it decreased only the accumulation of sugars, without affecting the accumulation of anthocyanins. The results of the second study showed that the modification of crop size by shoot thinning significantly affected the measured yield parameters, whereas the effect on Brix and anthocyanins was seasonally dependent. It was concluded that among the studied techniques, severe shoot trimming at late veraison is the most effective way to reduce sugar content in the berry without affecting the accumulation of anthocyanins.

Transcriptome and Metabolomics Integrated Analysis Reveals Terpene Synthesis Genes Controlling Linalool Synthesis in Grape Berries

In this study, four hybrids from the cross between "Italia" and "Tamina" grapes were chosen to investigate their distinct monoterpenoids patterns and candidate genes involved. Monoterpenoid profiles and transcriptome data were generated at four berry developmental stages. Trans-rose oxide, cis-rose oxide, citronellol, neral, nerol, nerol oxide, geraniol, geranial, geranic acid, and cis-isogeraniol were the dominant compounds in R250 hybrid, while linalool, hotrienol, linalool oxide pyranoside, and cis-furan linalool oxide were the main compounds in R77 hybrid. Six TPS-g subfamily genes were found related with the contents of linalool and its related monoterpenoids by weighted gene coexpression network analysis (WGCNA) and phylogenetic analysis. Among them, TPS59 was cloned and functionally verified by transient overexpression in the leaves of Vitis quinquangularis. Meanwhile, NAC (newGene_195), C2C2-GATA (VIT_15s0021g02510), and bHLH (VIT_14s0128g00110) were selected as candidate transcription factors (TFs) that could regulate the expression of the six TPS-b genes. These data enhanced our understanding on the regulation of monoterpenoid biosynthesis in grapes.

Developmental Regulation of Transcription in Touriga Nacional Berries under Deficit Irrigation.

Grapevine (Vitis vinifera L.) is one of the most economically important crops worldwide, especially due to the economic relevance of wine production. Abiotic stress, such as drought, may contribute to low yield, shifts in quality, and important economic loss. The predicted climate change phenomena point to warmer and dryer Mediterranean environmental conditions; as such, it is paramount to study the effects of abiotic stress on grapevine performance. Deficit irrigation systems are applied to optimize water use efficiency without compromising berry quality. In this research, the effect of two deficit irrigation strategies, sustained deficit irrigation (SDI) and regulated deficit irrigation (RDI), in the grape berry were assessed. The effects of different levels of drought were monitored in Touriga Nacional at key stages of berry development (pea size, véraison, and full maturation) through RNA-Seq transcriptome analysis and by specific differentially expressed genes (DEGs) monitoring through RT-qPCR. Handy datasets were obtained by bioinformatics analysis of raw RNA-Seq results. The dominant proportion of transcripts was mostly regulated by development, with véraison showing more upregulated transcripts. Results showed that primary metabolism is the functional category more severely affected under water stress. Almost all DEGs selected for RT-qPCR were significantly upregulated in full maturation and showed the highest variability at véraison and the lowest gene expression values in the pea size stage.

A Comparison of the Effects of Several Foliar Forms of Magnesium Fertilization on ‘Superior Seedless’ (Vitis vinifera L.) in Saline Soils

Magnesium (Mg) is the most essential element constituent in chlorophyll molecules that regulates photosynthesis processes. The physiological response of ‘Superior Seedless’ grapes was evaluated under different foliar magnesium fertilization such as sulfate magnesium (MgSO4·7 H2O), magnesium disodium EDTA (Mg-EDTA), and magnesium nanoparticles (Mg-NPs) during the berry development stages (flowering, fruit set, veraison, and harvest). In general, the ‘Superior Seedless’ vine had a higher performance in photosynthesis with Mg-NPs application than other forms. The Fy/Fm ratio declined rapidly after the fruit set stage; then, it decreased gradually up until the harvesting stage. However, both MgSO4 and Mg-EDTA forms showed slight differences in Fv/Fm ratio during the berry development stages. The outcomes of this research suggest that the Fv/Fm ratio during the growth season of the ‘Superior Seedless’ vine may be a good tool to assess magnesium fertilization effects before visible deficiency symptoms appear. Mg-NPs are more effective at improving ‘Superior Seedless’ berry development than the other magnesium forms. These findings suggest that applying foliar Mg-NPs to vines grown on salinity-sandy soil alleviates the potential Mg deficiency in ‘Superior Seedless’ vines and improves bunches quality.

Optimization of an In Vitro Embryo Rescue Protocol for Breeding Seedless Table Grapes (Vitis vinifera L.) in Italy

Conventional crossing of stenospermocarpic grapes for the obtainment of seedless cultivars presents some technical constraints causing embryo abortion in the early berry developmental stages. Embryo rescue technique partially overcomes these limitations, but the obtainment of viable plantlets relies on the optimization of several genetic and methodological issues. This work aimed to regenerate viable plants from immature ovules of stenospermocarpic table grape hybrids by applying a three-step in vitro culture protocol consisting of embryo development, embryo germination-rooting, and plantlet formation. The influence of parental genotypes (six “seedless × seedless” crosses), ovule sampling time (30, 40, 50 days after pollination (DAP)), and extent of embryo germination induction (4, 6, 8 weeks) was assessed on ovule fertilization, embryo development and germination, rooting, and plantlet formation to establish the best rescue time for each combination hybrid. Our optimized protocol included immature ovule isolation for 40 DAP and embryo germination induction for 8 weeks. As for genotypes, the most efficient embryo germination was recovered from hybrids of Thompson, Superior, and Regal cultivars, whereas the highest percentage of viable plants was derived from 50-DAP ovules of Luisa × Thompson progeny. Such an optimized protocol could be useful to maximize the efficiency of future breeding programs for grape seedlessness.

Quality Responses of Table Grapes ‘Flame Seedless’ as Effected by Foliarly Applied Micronutrients

Micronutrient (iron, zinc and boron) deficiencies are a basic and prominent factor affecting grape quality and yield in the Pothwar region. To overcome these deficiencies, different levels of micronutrients were applied foliarly on grapevines at five different berry developmental stages during two consecutive growing seasons (2018 and 2019). The data suggested that foliar treatment of micronutrients significantly increased the yield, number of bunches per vine, bunch weight, yield per vines, bunch length, berry number per cluster, berry diameter, berry weight and cluster compactness. The biochemical quality attributes of berries, including sugars (reducing, non-reducing as well as total sugars), ascorbic acid content, pH and TSS values, were at their highest levels in grapevines supplemented with Fe, Zn and B treatment at 200 ppm, respectively, i.e., the highest concentrations used. Biochemical leaf values, including chlorophyll a and b and leaf micronutrient content (Fe, Zn and B), were also highest in grapevines that were sprayed with Fe, Zn and B at 200 ppm. Overall, the results revealed that the performance of grapevine cv. ‘Flame Seedless’ growing in agroclimatic conditions of the Pothwar region was improved as a result of the foliar application of Fe, Zn and B at 200 ppm. The results also suggested that a further increase in the concentration of each nutrient might be helpful to obtain berries of improved quantity and quality.

Evolution of volatile compounds composition during grape berry development at the germplasm level

Volatile organic compounds (VOCs) are typically important factors in fleshy fruit crop quality. However, qualitative, and quantitative changes of VOCs profiles during grape berry development between different germplasms are not well understood. We surveyed VOCs composition and concentration at three berry development stages (fruit-set, veraison and maturation) in sixty-two grape accessions, and analyzed the relationship between monoterpenes contents and TERPENE SYNTHASE (TPS) genes expression. We identified ninety-four VOCs and observed different patterns of VOCs production through development among the different accessions. Total VOCs levels and the abundance of aldehydes, the most abundant VOCs at all three developmental stages, increased during berry development. Monoterpenes, hydrocarbons, and ketones levels peaked at maturation stage, while alcohols, sesquiterpenes and C13-noisoprenes had the highest concentrations at fruit-set. Correlation analysis indicated that several genes annotated as TPS contribute to monoterpene biosynthesis. These results have promoted the study of VOCs production in grape.

Growth, Yield, and Bunch Quality of "Superior Seedless" Vines Grown on Different Rootstocks Change in Response to Salt Stress.

The growth and quality of vines are negatively affected by soil salinity if enough salts accumulate in the root zone. As part of the current study, we estimated the remediating effects of rootstocks under salinity. For this reason, “superior seedless” vines were grafted onto three different rootstocks, such as SO4, 1103 Paulson, and own-root (“superior seedless” with their own-root). The experiment was conducted in the 2019 and 2020 seasons. This study examines the effects of different rootstocks on vine growth, yield, and quality using “superior seedless” vines grown in sandy soil with salinity. Four stages of berry development were examined (flowering, fruit set, veraison, and harvest time). At harvest, yield characteristics (clusters per vine and cluster weight) were also assessed. Each parameter of the growth season was influenced separately. The K+ and Na+ ratios were also significantly increased, as were the salinity symptoms index and bunch yield per vine and quality. Rootstock 1103 Paulson improved photosynthetic pigments, K+ accumulation, Na+ uptake, and cell membrane damage in “superior seedless” vines compared to other rootstocks, according to the study results. As determined in the arid regions of northwestern Egypt, the 1103 Paulson can mitigate salinity issues when planting “superior seedless” vines on sandy soil.

Effects of leaf removal on hexose accumulation and the expression of sugar unloading-related genes in syrah grapes

Leaf removal (LR) around the cluster zone is a common practice for regulating grape quality. The purpose of this study was to assess the effects of cluster-zone leaf removal, applied at the pea-size stage of berry development, on berry soluble sugar, organic acid and phenolic compound, sugar unloading-related gene expression of Vitis. vinifera L. Syrah. Four different severities of leaf removal were applied: no leaf removal (Control), removing 2 leaves above the cluster (LR1), removing 4 leaves above the cluster (LR2), and removing 6 leaves above the cluster (LR3). The three leaf removal treatments (LR), especially removing 4 leaves (LR2), resulted in significantly higher reducing sugar, soluble sugar (glucose, fructose and sucrose), total anthocyanin and citric acid contents as compared to the control group during ripening for both vintages. At harvest, the LR treatments increased the transcript abundance of most sugar unloading-related genes. In addition, VvHT3, VvHT5, VvSUC11, VvSUC12, VvSS and VvcwINV were positively correlated with both reducing sugar contents and soluble sugar contents. Our results suggest that removing 4 leaves above the cluster is useful for improving the quality of Syrah (Vitis vinifera L.) grapes in cool climate regions with excessive leaves. These findings provide insights into the molecular basis of the relationship between leaf removing and hexose (glucose and fructose) accumulation in the grape berries.