Vinifera Cv Research Articles

First report of Colletotrichum siamense causing grape ripe rot in Brazil.

Vitis vinifera cv. BRS Vitória is a seedless black table grape cultivar with an extremely pleasant flavor and is adapted to cultivation in all Brazilian regions. Between November and December 2021, grape berries presenting typical ripe rot symptoms were found in three vineyards located in Petrolina, Pernambuco Brazil. The first symptoms are small and depressed lesions on ripe berries, presenting tiny black acervuli. As the disease progress, lesions enlarge and affect the whole fruit, and abundant orange masses of conidia can be observed. Finally, berries become completely mummified. Symptoms were observed in the three vineyards visited, and disease incidence was above 90%. Some producers are considering eradicating the plantations due to the losses caused by the disease. Control measures used so far are costly and ineffective. Fungal isolation was performed by transferring conidial masses from 10 diseased fruit to plates containing potato dextrose agar medium. Cultures were incubated at 25 °C under continuous light. Seven days after inoculation, three fungal isolates (LM1543-1545) were obtained and subcultivated in pure culture for species identification and pathogenicity test. Isolates presented white to grey cottony mycelia, and hyaline conidia with cylindrical with rounded ends, which resemble the genus Colletotrichum (Sutton 1980). Partial sequences of APN2-MAT/IGS, CAL, and GAPDH loci were amplified, sequenced, and deposited on GenBank (OP643865-OP643872). Isolates from V. vinifera were placed within the clade including the ex-type and representative isolates of C. siamense. The clade was strongly supported (99.8% bootstrap support) in the maximum likelihood multilocus tree of the three loci combined, which confidently assign the isolates to this species. Inoculation on grape bunches was performed to confirm pathogenicity. Grape bunches were surface sterilized for 30 s in 70% ethanol, 1 min in 1.5% NaOCl, rinsed two times with sterile distilled water, and air-dried. Fungal conidial suspensions (106 conidia mL-1) were sprayed to the point of run-off. The negative control was represented by grape bunches sprayed with sterile distilled water. Grape bunches were kept in a humid chamber for 48 h at 25 °C and a light period of 12 h. The experiment was conducted with four replicates (four inoculated bunches per isolate) and repeated once. Typical ripe rot symptoms were observed on grape berries 7 days after inoculation. No symptoms were observed on the negative control. The fungal isolates recovered from inoculated berries were morphologically identical to the C. siamense isolates originally recovered from symptomatic berries collected in the field, fulfilling Koch's postulates. Colletotrichum siamense was reported in association with grape leaves in USA (Weir et al. 2012) and causing grape ripe rot in North America (Cosseboom & Hu 2022). Only C. fructicola, C. kahawae, C. karsti, C. limetticola, C. nymphaeae and C. viniferum were reported causing grape ripe rot in Brazil (Echeverrigaray et al. 2020). To our knowledge, this is the first report of C. siamense causing grape ripe rot in Brazil. This finding is important for disease management because C. siamense has a high phytopathogenic potential due to its wide distribution and host range.

The Impact of a Commercial Biostimulant on the Grape Mycobiota of Vitis vinifera cv. Barbera.

Reducing the use of fungicides, insecticides, and herbicides in order to limit environmental pollution and health risks for agricultural operators and consumers is one of the goals of European regulations. In fact, the European Commission developed a package of measures (the European Green Deal) to promote the sustainable use of natural resources and strengthen the resilience of European agri-food systems. As a consequence, new plant protection products, such as biostimulants, have been proposed as alternatives to agrochemicals. Their application in agroecosystems could potentially open new scenarios regarding the microbiota. In particular, the vineyard microbiota and the microbiota on the grape surface can be affected by biostimulants and lead to different wine features. The aim of this work was to assess the occurrence of a possible variation in the mycobiota due to the biostimulant application. Therefore, our attention has been focused on the yeast community of grape bunches from vines subjected to the phytostimulant BION®50WG treatment. This work was carried out in the CREA-VE experimental vineyard of Vitis vinifera cv. Barbera in Asti (Piedmont, Italy). The composition of fungal communities on grapes from three experimental conditions such as IPM (integrated pest management), IPM+BION®50WG, and IPM+water foliar nebulization was compared by a metabarcoding approach. Our results revealed the magnitude of alpha and beta diversity, and the microbial biodiversity index and specific fungal signatures were highlighted by comparing the abundance of yeast and filamentous fungi in IPM and BION®50WG treatments. No significant differences in the mycobiota of grapevines subjected to the three treatments were detected.

The pivotal role of high-resolution mass spectrometry in the study of grape glycosidic volatile precursors for the selection of grapevines resistant to mildews.

A breeding program to produce new grape varieties tolerant to main vine fungal pathogens (Plasmopara viticola and Erysiphe necator) is carrying out by crossing Vitis vinifera cv. "Glera" with resistant genotypes such as "Solaris," "Bronner," and "Kunleany." Firstly, resistance gene-based markers analyses allowed the identification of five genotypes, which have inherited the resistance loci against mildews. To select those that also inherited the phenotype as close as possible to 'Glera' suitable to be introduced in the Prosecco wine production protocols, the grape glycosidic derivatives were studied by UHPLC/QTOF mass spectrometry. Targeted identification of the metabolites was performed using a database expressly constructed by including the glycosidic volatile precursors previously identified in grape and wine. A total of 77 glycosidic derivatives including many aroma precursors and some variety markers, were identified. Original resistant genotypes had distinct metabolomic profiles and different to 'Glera', while the crossings showed varying similarity degrees to V. vinifera parent. Findings demonstrated the Glera × Bronner and Glera × Solaris crossings are more suitable to produce high-sustainable Prosecco wines. Coupling of glycosidic volatile precursors profilingto multivariate statistical analysis was effective for phenotypic characterization of grapes and to evaluate their enological potential.

UV-B Radiation Induced the Changes in the Amount of Amino Acids, Phenolics and Aroma Compounds in Vitis vinifera cv. Pinot Noir Berry under Field Conditions.

High UV-B radiation can challenge Pinot noir growth in the wine-making region of the Southern Hemisphere. The aim of this work was to determine UV-B effects on amino acids, phenolic composition and aroma compounds of Pinot noir fruit. Sunlight exposure with or without UV-B did not affect fruit production capacity, °Brix and total amino acids in the vineyard over the two years. This research reported increased contents of skin anthocyanin and skin total phenolics in berry skins under UV-B. The research showed that there were no changes in C6 compounds. Some monoterpenes concentrations were decreased by UV-B. The information also indicated how important leaf canopy management was for vineyard management. Therefore, UV radiation potentially affected fruit ripeness and crop load, and even stimulated the accumulation of phenolic compounds that may affect Pinot noir quality. This research reported that canopy management (UV-B exposure) may be a good way for vineyard management to increase the accumulation of anthocyanins and tannins in berry skins.

Correlation between dehydrin-like proteins and cold hardiness of grapevine

Winter survival of Vitis vinifera Linnaeus in cool climate viticultural areas can be jeopardized due to inadequate cold hardiness. Dehydrins are a family of proteins commonly found in plant tissue in response to dehydration stress and cold exposure. To determine their presence and relationship to cold hardiness in overwintering grapevines, compound buds of V. vinifera cv. Sauvignon blanc were sampled from a commercial vineyard every 2–3 weeks throughout the 2016–2017 winter. Proteins were extracted and separated by SDS–PAGE, and potential dehydrins were immunoblotted with a commercial antibody raised against the dehydrin K-segment consensus sequence. Six protein bands were identified in four Sauvignon blanc clones at 23, 26, 35, 41, 48, and 90 kDa, showing a serological relation to dehydrins due to their reaction with the K-segment antibody. The bands at 23, 41, 48, and 90 kDa were confirmed as dehydrins following trypsin digestion and liquid chromatography with tandem mass spectrometry with Mascot analysis. Their fluctuations throughout the dormant season were quantified by immunoblotting, and three patterns emerged, the 23, 26, and 35 kDa proteins peaked immediately prior to deacclimation; the 41 and 48 kDa proteins peaked during maximum hardiness and decreased towards deacclimation, while the 90 kDa plateaued during the same period. Maximum hardiness and relative dehydrin band intensity were positively correlated ( p < 0.050) for all but the 23 kDa protein. The variation in accumulation patterns and relationships to cold hardiness indicates that these dehydrin proteins are likely regulated by different molecular processes and could play different roles in cryoprotection throughout dormancy.

Dynamics of starch degradation and expression of related genes during chilling stress in grapevine

Frost in late spring is one form of environmental stress that severely damages grapevines. Starch is a major product of photosynthesis that plays essential roles in many biological processes in plants. The dynamics of starch metabolism and related gene expression in the leaves of grapevine during chilling stress have remained unclear. Here, starch metabolism in the leaves of Vitis vinifera cv. Cabernet Sauvignon was characterized under normal (25℃) and late-spring frost mimic (4℃) conditions. The results from anthracenone colorimetry, iodine staining and ultrathin sectioning are consistent with a low temperature during the night inhibiting the degradation of starch. Four α-amylases (AMY) and ten β-amylases (BAM) genes were identified in the V. vinifera genome (PN40024). Low nighttime temperatures downregulated the expression of genes that encode amylases relative to optimal nighttime temperatures. The expression of other genes with functions related to starch degradation, such as like starch excess four 1 (LSF1) and isoamylase 3 (ISA3), was induced by low temperature. The glucose, sucrose, maltose, and fructose contents increased in plants grown under low-temperature conditions with less consumption of starch, indicating complex regulation of soluble sugars. The findings here provide clues that will lead to enhanced frost tolerance of grapevine leaves by modifying the starch degradation pathway.

Heritage grapevines as sources of biological control agents for Botryosphaeria dieback pathogens

Grapevine trunk diseases cause severe damage in grapevines. Management strategies focus on protection of grapevine pruning wounds using chemical fungicides or biological control agents. Botryosphaeria dieback, caused mainly by Lasiodiplodia spp., is one of the main trunk diseases in northwest Mexico. This study obtained endophytic bacteria and fungi from the heritage grapevine Vitis vinifera cv. ‘Mission’ for potential biological control of Botryosphaeria dieback. A collection of 135 bacterial and 37 fungal isolates were obtained and initially tested for antagonistic activity against Lasiodiplodia brasiliensis. The most promising isolates belonging to Trichoderma and Bacillus spp. were selected and characterized to determine their modes of action. Bacillus isolates produced volatile organic compounds that inhibited growth of Neofusicoccum parvum, and diffusible organic compounds with antifungal effects against L. brasiliensis and N. parvum. Trichoderma isolates produced diffusible organic compounds and were mycoparasites. In greenhouse assays, plants inoculated with three Trichoderma asperellum isolates (T20BCMX, EF09BCMX, and EF11BCMX), B. amyloliquefaciens (BEVP26BCMX) or Bacillus sp. (rbES015), applied preventively in soil, gave up to 50% smaller necrotic lesions when compared with the plants inoculated only with L. brasiliensis. In the field, plants inoculated with three Bacillus isolates (BEVP02BCMX, BEVP26BCMX, BEVP31BCMX) or five Trichoderma (T11BCMX, T15BCMX, T17BCMX, T20BCMX, and EF11BCMX) had lesions up to four times smaller than control plants inoculated only with L. brasiliensis. This study has demonstrated the potential of heritage grapevines to provide biological control agents for Botryosphaeria dieback.

Amino acid substitutions in grapevine (Vitis vinifera) acetolactate synthase conferring herbicide resistance

Acetolactate synthase genes (ALS) have successfully been modified for providing resistance to ALS-inhibiting herbicides in many plant species. Based on sequence and expression analyses, we confirmed VvALS1 as the best functional ALS candidate in grapevine. To develop an ALS-based herbicide selection system for facilitating grape transformation, we firstly evaluated the responses of Vitis vinifera cv Chardonnay callus and young in vitro shoots of Vitis vinifera cv Thompson Seedless to several representative ALS-inhibiting herbicides and found a typical linear response curves to some of the herbicides, including chlorsulfuron and imazapyr belonging to the sulfonylurea or imidazolinone families, respectively. Secondly, we created constructs containing amino acid substitutions in the domains which are known to be critical to herbicide resistance and generated transgenic plants for 3 amino acid substitutions using Agrobacterium-mediated transformation of meristematic bulk tissues of Thompson Seedless. Finally, we showed that ectopic expression of two amino acid substitutions (P191S and P191T) at the N-terminal region and another (W568L) at C-terminal region in VvALS resulted in high resistance to chlorsulfuron or imazapyr herbicides in transgenic in vitro shoots. Our work highlighted the potential use of VvALS mutations imparting herbicide resistance as a selectable marker in grapevine transformation research and as a means in fostering grapevine improvement via cisgenesis, paving the way for developing a selectable co-editing system to facilitate transgene-free gene-editing.

Changes in Polyphenols and Anthocyanin Pigments during Ripening of Vitis vinifera cv Maratheftiko: A Two-Year Study

The vineyard of Cyprus is comprised largely of native Vitis vinifera varieties, which are rather underexploited with regard to wine production to date. Although empirical observations concur that several of these varieties may possess a high potential for the production of quality wines, analytical data pertaining to their polyphenolic composition are scarce. This study was undertaken with the aim of providing a detailed picture of the evolution patterns of several important polyphenolic constituents during the last stages of ripening of Maratheftiko, which is one of the major native grape varieties. This study included monitoring of representative simple phenolics, flavonoids and anthocyanin pigments for two consecutive years, 2021 and 2022, to obtain a more integrated portrayal of changes occurring during the critical period prior to harvest. It was revealed that there was a very high difference in the content of almost all polyphenols considered for the harvests in 2021 and 2022. The grapes harvested in 2022 had a much higher content in catechin, but most importantly, the content in total anthocyanins was 3.91-fold higher in 2022 compared to 2021. On the other hand, trans-resveratrol was the only polyphenolic metabolite whose difference was rather marginal. In seeds, the predominant substance was catechin, which displayed pronounced fluctuations during the period examined. It was concluded that the contents of major polyphenolic metabolites in Maratheftiko grapes might exhibit large variations during the period prior to harvest, most possibly reflecting differences in the average temperature and rainfall. Thus, tight monitoring of technologically important constituents, e.g., anthocyanins, is recommended to ensure the harvest of grapes with optimal maturity.

A Chronological Study on Grapevine Leafroll-Associated Virus 2 in Australia.

Grapevine leafroll disease affects the health status of grapevines worldwide. Most studies in Australia have focused on grapevine leafroll-associated viruses 1 and 3, while little attention has been given to other leafroll virus types, in particular, grapevine leafroll-associated virus 2 (GLRaV-2). A chronological record of the temporal occurrence of GLRaV-2 in Australia since 2001 is reported. From a total of 11,257 samples, 313 tested positive, with an overall incidence of 2.7%. This virus has been detected in 18 grapevine varieties and Vitis rootstocks in different regions of Australia. Most varieties were symptomless on their own roots, while Chardonnay showed a decline in virus-sensitive rootstocks. An isolate of GLRaV-2, on own-rooted Vitis vinifera cv. Grenache, clone SA137, was associated with severe leafroll symptoms after veraison with abnormal leaf necrosis. The metagenomic sequencing results of the virus in two plants of this variety confirmed the presence of GLRaV-2, as well as two inert viruses, grapevine rupestris stem pitting-associated virus (GRSPaV) and grapevine rupestris vein feathering virus (GRVFV). No other leafroll-associated viruses were detected. Among the viroids, hop stunt viroid and grapevine yellow speckle viroid 1 were detected. Of the six phylogenetic groups identified in GLRaV-2, we report the presence of four groups in Australia. Three of these groups were detected in two plants of cv. Grenache, without finding any recombination event. The hypersensitive reaction of certain American hybrid rootstocks to GLRaV-2 is discussed. Due to the association of GLRaV-2 with graft incompatibility and vine decline, the risk from this virus in regions where hybrid Vitis rootstocks are used cannot be overlooked.

GrapevineXL reliably predicts multi-annual dynamics of vine water status, berry growth, and sugar accumulation in vineyards.

Climate and water availability greatly affect each season's grape yield and quality. Using models to accurately predict environment impacts on fruit productivity and quality is a huge challenge. We calibrated and validated the functional-structural model, GrapevineXL, with a data set including grapevine seasonal midday stem water potential (Ψxylem), berry dry weight (DW), fresh weight (FW), and sugar concentration per volume ([Sugar]) for a wine grape cultivar (Vitis vinifera cv. Cabernet Franc) in field conditions over 13years in Bordeaux, France. Our results showed that the model could make a fair prediction of seasonal Ψxylem and good-to-excellent predictions of berry DW, FW, [Sugar] and leaf gas exchange responses to predawn and midday leaf water potentials under diverse environmental conditions with 14 key parameters. By running virtual experiments to mimic climate change, an advanced veraison (i.e. the onset of ripening) of 14 and 28days led to significant decreases of berry FW by 2.70% and 3.22%, clear increases of berry [Sugar] by 2.90% and 4.29%, and shortened ripening duration in 8 out of 13 simulated years, respectively. Moreover, the impact of the advanced veraison varied with seasonal patterns of climate and soil water availability. Overall, the results showed that the GrapevineXL model can predict plant water use and berry growth in field conditions and could serve as a valuable tool for designing sustainable vineyard management strategies to cope with climate change.

Two ways to die: Species dependent PCD modes in grapevine cells

Programmed cell death (PCD) is considered as a hallmark of strain-specific immunity. In contrast, generic basal immunity is thought to act without PCD. This classical bifurcation has been questioned during recent years. Likewise, the role of jasmonate signalling for these two modes of innate immunity has remained ambiguous. We have addressed both questions using two closely related grapevine cell lines (V. rupestris, V. vinifera cv. ‘Pinot Noir’) that contrast in their cell-death response to the bacterial elicitor harpin and the hormonal trigger methyl jasmonate (MeJA). We follow different cellular (loss of membrane integrity, mortality), molecular (induction of transcripts for phytoalexin synthesis and for metacaspases), as well as metabolic (sphingolipid profiles) responses to the two triggers in the two cell lines. The role of NADPH oxidases and induction of transcripts for the class-II metacaspases MC5 differ qualitatively between the two cell lines. We tested a possible role of sphingolipid metabolism but can rule this out. We propose a model, where V. rupestris, originating from co-evolution with several biotrophic pathogens, readily activates a hypersensitive cell death in response to harpin, while the context of MeJA-induced cell death in ‘Pinot Noir’ might not be related to immunity at all. We propose that the underlying signalling is modular, recruiting metacaspases differently depending on upstream signalling.

Improving Grapevine Heat Stress Resilience with Marine Plant Growth-Promoting Rhizobacteria Consortia.

Amid climate change, heatwave events are expected to increase in frequency and severity. As a result, yield losses in viticulture due to heatwave stress have increased over the years. As one of the most important crops in the world, an eco-friendly stress mitigation strategy is greatly needed. The present work aims to evaluate the physiological fitness improvement by two marine plant growth-promoting rhizobacteria consortia in Vitis vinifera cv. Antão Vaz under heatwave conditions. To assess the potential biophysical and biochemical thermal stress feedback amelioration, photochemical traits, pigment and fatty acid profiles, and osmotic and oxidative stress biomarkers were analysed. Bioaugmented grapevines exposed to heatwave stress presented a significantly enhanced photoprotection capability and higher thermo-stability, exhibiting a significantly lower dissipation energy flux than the non-inoculated plants. Additionally, one of the rhizobacterial consortia tested improved light-harvesting capabilities by increasing reaction centre availability and preserving photosynthetic efficiency. Rhizobacteria inoculation expressed an osmoprotectant promotion, revealed by the lower osmolyte concentration while maintaining leaf turgidity. Improved antioxidant mechanisms and membrane stability resulted in lowered lipid peroxidation product formation when compared to non-inoculated plants. Although the consortia were found to differ significantly in their effectiveness, these findings demonstrate that bioaugmentation induced significant heatwave stress tolerance and mitigation. This study revealed the promising usage of marine PGPR consortia to promote plant fitness and minimize heatwave impacts in grapevines.

Mycorrhizal symbiosis improve fruit quality in Tempranillo grapevine sensitive to low-moderate warming

An adequate clonal selection could help the adaptation of Vitis vinifera cv. Tempranillo to warming. Moreover, the resilience of Tempranillo to elevated air temperatures increases when associated with arbuscular mycorrhizal fungi (AMF). Our objective was to assess if mycorrhizal association can counteract the deleterious effect of elevated temperatures on plant performance and fruit quality in clones (CL) highly sensitive to warming. Fruit bearing cuttings of Tempranillo CL-843 were cultivated under greenhouse conditions. Assay included plants inoculated (+M) or not (-M) with AMF and grown at either 24/14°C or 28/18°C day/night air temperatures. Elevated temperatures shortened the period between fruit set and veraison in both –M and +M plants and also the period between veraison and maturity in +M plants. Photosynthetic rates were higher under warm temperatures irrespective of mycorrhizal inoculation, but sugars and proteins in leaves decreased in -M plants under these environmental conditions. Warming induced the accumulation of Ca, P, Cu and Mn in leaves of all plants and those of Mg and Zn in a greater extent in +M plants. Only in +M plants mature berries maintained the balance of sugars to organic acids and increased the Arg-to Pro-ratio under elevated temperatures. The association of Tempranillo with AMF may result in a more adequate source of N for yeasts during the must fermentation process and could mitigate the increased pH and ethanol levels found in the wines elaborated with grapes developed under low-moderate warming. However, extrapolating these findings to fields in the Mediterranean region or areas subjected to intense warming and frequent heatwaves deserves further study.

Influence of non-irrigation and seasonality on wine colour, phenolic composition and sensory quality of a grapevine (<i>Vitis vinifera</i> cv. Callet) in a Mediterranean climate

Most vineyards in Mediterranean areas are cultivated using a training system and drip irrigation. However, the increasing risk of water deficit stress due to global warming will mean that viticulture need to adapt to a tougher water-saving policy. Thus, we investigated the effects of total suppression of irrigation on a grapevine (Vitis vinifera cv. Callet) and the phenolic composition and sensory quality of this native red variety wine from the Balearic Islands over three seasons. Significant yield reductions of up to 15.6 %, 17.2 % and 22.2 % were observed in non-irrigated (NI) plants in 2016, 2017 and 2018 respectively, compared to irrigated plants (I); however, wine quality parameters improved. In the years with the highest rainfall (715 mm in 2016 and 799 mm in 2017), NI favoured the enrichment of sugars, anthocyanins and phenolic compounds in the wine and enhanced the development of aromatic components. However, with lower rainfall (524 mm in 2018), the NI treatment appeared to diminish the quality of the wine, particularly affecting the global sensory quality of the wines. Thus, development of specific water strategies tailored to the vineyard, year, vintage and grape variety may regulate the phenolic composition of red wines to meet production goals and reduce total water consumption.

Influence of late pruning practice on two red skin grapevine cultivars in a semi-desert climate.

Continually increasing global temperature could severely affect grape berry metabolite accumulation and ultimately wine polyphenol concentration and color intensity. To explore the effect of late shoot pruning on grape berry and wine metabolite composition, field trials were carried out on Vitis vinifera cv. Malbec and cv. Syrah grafted on 110 Richter rootstock. Fifty-one metabolites were detected and unequivocally annotated employing UPLC-MS based metabolite profiling. Integrating the data using hierarchical clustering showed a significant effect of late pruning treatments on must and wine metabolites. Syrah metabolite profiles were characterized by a general trend of higher metabolite content in the late shoot pruning treatments, while Malbec profiles did not show a consistent trend. In summary, late shoot pruning exerts a significant effect, though varietal specific, on must and wine quality-related metabolites, possibly related to enhanced photosynthetic efficiency, which should be taken into consideration when planning mitigating strategies in warm climates.

Integrated Transcriptome and Metabolome Dissecting Interaction between Vitis vinifera L. and Grapevine Fabavirus.

Grapevine fabavirus (GFabV) is a novel member of the Fabavirus genus associated with chlorotic mottling and deformation symptoms in grapevines. To gain insights into the interaction between GFabV and grapevines, V. vinifera cv. 'Summer Black' infected with GFabV was investigated under field conditions through physiological, agronomic, and multi-omics approaches. GFabV induced significant symptoms on 'Summer Black', and caused a moderate decrease in physiological efficiency. In GFabV-infected plants, alterations in carbohydrate- and photosynthesis-related genes might trigger some defense responses. In addition, secondary metabolism involved in plant defense was progressively induced by GFabV. Jasmonic acid and ethylene signaling were down-regulated in GFabV-infected leaves and berries along with the expression of proteins related to LRR and protein kinases, suggesting that GFabV can block the defense in healthy leaves and berries. Furthermore, this study provided biomarkers for early monitoring of GFabV infection in grapevines, and contributed to a better understanding of the complex grapevine-virus interaction.

First report of Colletotrichum gloeosporioides causing anthracnose on grapevine (Vitis vinifera) in Shaanxi province, China.

Grape anthracnose caused by Colletotrichum spp. is an economically important disease in most vineyards during rainy and humid weather. In June 2021, widespread anthracnose was observed in leaves of Vitis vinifera cv. Red Globe in Yangling city (latitude = 34.28, longitude = 108.07), Shaanxi Province. Diseased plants exhibited circular brown necrotic lesions with yellow borders in young leaves (Fig. 1A). Approximately 80% of the 75 grape plants showed disease symptoms that were consistent with those previously reported for anthracnose on grape caused by C. acutatum, C. gloeosporioides, and C. viniferum (Hong et al. 2008; Oo and Oh 2017). To isolate the pathogen, ten diseased leaves were collected. Small pieces (0.5 mm × 0.5 mm) of symptomatic tissue were surface sterilized with 75% alcohol for 30 s, transferred to 4% NaClO for 2 min, and then washed twice with sterile distilled water. The pathogen was isolated and cultured on potato dextrose agar (PDA) at 25 °C with a 12 h light/dark photoperiod. Hyphal tips of the isolate were transferred to fresh PDA after 1 day. Acervuli were formed after 15 days on PDA. The colonies were single-spored to obtain pure cultures. Pure cultures on PDA appear white to grey, and the reverse of the colonies was olive gray or yellowish white (Fig. 1B, C). Conidia were single-celled, hyaline, straight cylindrical with ends rounded, and measured 12.50 to 17.78 μm (length) (mean=15.19 μm, n=50) × 3.66 to 5.82 μm (width) (mean=4.48 μm, n=50) (Fig. 1D). The morphological characteristics matched the previous descriptions of C. gloeosporioides by Sawant et al. (2012). For molecular identification, genomic DNA was extracted from isolate YLRG13, and the actin (ACT), internal transcribed spacer (ITS), and beta-tubulin (TUB2) were amplified using the primer pairs ACT-512F/ACT-783R (Carbone and Kohn 1999), ITS1F/ITS4 (White et al. 1990), and T1/T2 (O' Donnell and Cigelnik 1997), respectively. The ACT (OQ031183 and MZ686707), ITS (OP999326 and MZ669974), and TUB2 (OQ031184 and MZ686708) nucleotide sequences of isolates YLRG5 and YLRG13 were deposited in GenBank. BLASTn showed 99 to 100% similarity with C. gloeosporioides. Neighbor-joining trees based on the three genes was constructed using PAUP version 4.0b10. The results showed the isolated YLRG5 and YLRG13 from V. vinifera was closely related to C. gloeosporioides with high bootstrap values (Fig. S2). Pathogenicity testing was performed with isolate YLRG13 by 10 μL conidial suspension (4×108 conidia/ml) on the surfaces of five wounded detached leaves of six-year-old Vitis vinifera cv. Red Globe. Sterile distilled water was used as a control. Inoculated plants were placed in a humid chamber at 25 °C. Conidial germination was observed at 24 hours post-inoculation (Fig. S1E). Four days after inoculation, typical anthracnose symptoms developed on inoculated grape leaves (Fig. S1F). No symptoms were observed on the controls. The fungus reisolated from the symptomatic grape leaves showed the same morphological characteristics of the inoculated isolate, fulfilling Koch's postulates. To our knowledge, this is the first report of grape anthracnose caused by C. gloeosporioides in Northwestern of China. C. gloeosporioides was reported causing anthracnose on a wide variety of horticultural crops, such as almond, avocado, apple, banana, cashew, citrus, cucumber, grape, guava, mango, onion, papaya, passion fruit, pepper, strawberry, tomato, and watermelon (Sharma and Kulshrestha 2015), suggesting the potential cross-infection between grape and other horticultural crops.

Identification and expression analysis of autophagy-related gene family associated with embryonic development in seeded and seedless grapes (Vitis vinifera)

ABSTRACT Autophagy is an important protein degradation pathway in eukaryotes and is involved in multiple processes. To date, many autophagy-related genes had been studied in various plants, but a few studies have been reported on the role of autophagy in seed development. For centuries, seedlessness has been one of the most valuable characteristics of grapes. In this study, we identified a total of 33 ATG genes in the grape. Tissue-specific expression analysis showed that VvATGs expressed widely in V. vinifera cv. ‘Pinot Noir’, indicating autophagy has an extensive role in plant development. Furthermore, we analysed the expression profiles of VvATGs during seed development in stenospermocarpic seedless ‘Thompson Seedless’ and seeded grapes ‘Pinot Noir’, the results showed that most of VvATGs exhibited higher expression levels in stenospermocarpic seedless grapes than that of seeded ones, which implies the autophagic activity in seedless grapes is relatively brisk and VvATGs may involve in the seed abortion. And the yeast two-hybrid assay showed that VvATG7 protein interacted with VvATG10 and VvATG12 protein, respectively, indicating that they may form autophagy complex through protein interactionIn summary, the genome-wide identification, expression analysis, and protein interaction of VvATGs provide new insights regarding potential roles during plant embryonic development.

Protective effects of chitosan based salicylic acid nanocomposite (CS-SA NCs) in grape (Vitis vinifera cv. ‘Sultana’) under salinity stress

Salinity is one of the most important abiotic stresses that reduce plant growth and performance by changing physiological and biochemical processes. In addition to improving the crop, using nanomaterials in agriculture can reduce the harmful effects of environmental stresses, particularly salinity. A factorial experiment was conducted in the form of a completely randomized design with two factors including salt stress at three levels (0, 50, and 100 mM NaCl) and chitosan-salicylic acid nanocomposite at three levels (0, 0.1, and 0.5 mM). The results showed reductions in chlorophylls (a, b, and total), carotenoids, and nutrient elements (excluding sodium) while proline, hydrogen peroxide, malondialdehyde, total soluble protein, soluble carbohydrate, total antioxidant, and antioxidant enzymes activity increased with treatment chitosan-salicylic acid nanocomposite (CS-SA NCs) under different level NaCl. Salinity stress reduced Fm', Fm, and Fv/Fm by damage to photosynthetic systems, but treatment with CS-SA NCs improved these indices during salinity stress. In stress-free conditions, applying the CS-SA NCs improved the grapes' physiological, biochemical, and nutrient elemental balance traits. CS-SA NCs at 0.5 mM had a better effect on the studied traits of grapes under salinity stress. The CS-SA nanoparticle is a biostimulant that can be effectively used to improve the grape plant yield under salinity stress.