Grafting is increasingly used in watermelon ( Citrullus lanatus ) production in the United States to overcome soilborne disease and abiotic stress. This combination of plants often results in increased nutrient uptake, vegetative growth, and total yield. However, grafting to some cucurbit rootstocks can result in delayed watermelon harvests. To characterize differences in vegetative and flower development, as well as nutrient uptake due to scion and rootstock combination, reciprocal grafts of wild watermelon ( Citrullus amarus , ‘Carolina Strongback’), squash ( Cucurbita maxima Cucurbita moschata , ‘Super Shintosa’), and seedless watermelon (‘Fascination’) with each serving as a scion and rootstock for the other two species (nine reciprocal grafting treatments), as well as one ungrafted watermelon treatment, were examined in two repeated trials. The three grafted treatments with watermelon scions and the ungrafted watermelon treatment were dissected for identification of developing floral buds before grafting, after graft healing, and at transplanting. After transplanting in a glasshouse, the nodal position and date of male and female flowers were recorded for all 10 treatments before the plants were harvested to assess vegetative growth and tissue nutrient concentrations. Dissections of young watermelon plants revealed similar nodal positions of the first flower for all treatments (fourth node), although differences in the nodal position of the first open male flower after transplanting in the greenhouse were pronounced, with flowers occurring three to five nodes higher in grafted watermelon plants relative to ungrafted watermelon. In addition to altered positions, delays of 4 to 8 days for the first male flower and 3 to 5 days for the first female flower were observed for all grafted watermelon treatments relative to ungrafted watermelon in trial 2. These results suggest that development of previously developed flower buds is arrested in grafted plants. However, this arrested development did not consistently result in delayed flowering for all grafted treatments, likely due to greater overall development rate when grafted and to environmental conditions. We observed increased vine lengths in both trials and shoot dry weight (trial 1) in watermelon and wild watermelon scions grafted to squash rootstocks relative to their respective self-grafts (and ungrafted watermelon). However, squash rootstocks did not increase the number of growing points or the leaf area for either watermelon or wild watermelon scions compared with their self-grafts. For watermelon scions, ungrafted plants had similar numbers of growing points, leaf number, leaf area, and root dry mass to plants with squash and wild watermelon rootstocks. Dry shoot tissue concentrations of several micronutrients (Fe, B, Mn, and Zn) were found to be lower with squash rootstocks relative to other treatments in both watermelon and wild watermelon scions. Dry root tissue concentrations of Zn and Mn were also lower with squash rootstocks, suggesting limited uptake. Concentrations of other nutrients in dry root tissue were also lower in plants with squash rootstocks, although shoot concentrations were similar, suggesting more efficient translocation from root to shoot. Our results revealed that grafting can arrest the flower bud development, which may lead to flowering delay as affected by growing conditions and nutrient uptake and translocation.

Spring frost poses a major threat to grape-producing regions, severely reducing grape yield and quality. Grafting rootstocks is an effective strategy for enhancing scion resistance to spring frost and mitigating damage. In this study, the two wine grape cultivars (‘Cabernet Sauvignon’ and ‘Chardonnay’) grafted onto three rootstocks (‘Beta’, ‘Kober 5BB’, and ‘3309 Couderc’) were evaluated for their spring frost resistance on one-year-old vines. The scion–rootstock combinations exhibited significantly less photosynthetic impairment under frost stress compared with own-rooted vines. Rootstock also showed lower levels of proline accumulation in the roots and APX activities in the leaves under frost conditions. Compared with own-rooted vines, VvCBF1 gene expression were significantly upregulated in the grafted combinations under frost stress conditions. Among the tested rootstocks, ‘Kober 5BB’ markedly improved the spring frost resistance of both cultivars. CH/5BB exhibited the highest activities of POD and APX activity and the greatest induction of VvCBF genes, along with the lowest relative electrical conductivity and H2O2 content. These results highlight the critical role of rootstocks in improving scion spring frost resistance and provide important guidance for selecting suitable rootstocks to mitigate the impact of late frosts.

ABSTRACTGrafting has been fundamental in viticulture since the phylloxera crisis of the late 19th century; nevertheless, the functional consequences of vascular connection on the graft union remain poorly understood. The effects of grafting on Vitis vinifera cv. Tempranillo (Te) were evaluated using two complementary approaches: (1) cambial alignment, comparing completely aligned (CA) versus partially aligned (PA) unions; and (2) grafting and scion–rootstock interaction, comparing heterografts (Te/110R and Te/RG8), homografts (Te/Te), and ungrafted Te cuttings. These approaches were tested through three experiments: a vineyard trial and two pot trials under well‐watered (WW), moderate water stress (MWS), and recovery (R) regimes. In the vineyard, CA plants exhibited greater vegetative growth and gas exchange, particularly on 110R, whereas the vigorous RG8 rootstock mitigated the effects of misalignment. Under MWS conditions, CA adopted a drought‐avoidant strategy with earlier stomatal closure and higher root allocation, whereas PA maintained higher stomatal conductance, recovered photosynthesis faster after rewatering, and prioritised shoot and rootstock growth, especially on RG8. Finally, grafted plants were more sensitive to water stress than ungrafted plants, while homografts accumulated the greatest biomass and root investment, suggesting more efficient vascular connectivity compared with heterografts. Our study highlights that cambial alignment, grafting, and partner interactions influence plant development and physiological performance; however, long‐term studies are needed to clarify how vascular connectivity at the graft union affects transport processes, stress responses, and ultimately vine longevity under different scion–rootstock combinations.

Frequent and increasingly severe freezing events threaten citrus production in northern Florida, underscoring the need for strategies that enhance freezing resilience in citrus cultivars. Grafting scions onto tolerant rootstocks provides a physiologically integrative approach to improve stress tolerance. This study aims to elucidate how these interactions modulate physiological and metabolic responses under freezing stress, thereby identifying mechanisms that contribute to enhanced freeze resilience in citrus. Here, we grafted Citrus reticulata (cv. UF-950) onto eight rootstocks (Bitters, Blue-1, C-146, Sour Orange, UFR07TC, UFR09TC, UFR5, and US942) to evaluate scion–rootstock interactions under normal (20 °C) and freezing (−6 °C) conditions. Freezing stress caused a sharp increase in oxidative stress markers, lipid peroxidation, and membrane damage while reducing photosynthetic performance across most combinations. Antioxidant capacity, osmolyte accumulation, and carbon–nitrogen metabolic responses varied significantly among rootstocks, revealing strong genotype-dependent modulation of scion physiology. Among the tested combinations, UF-950 grafted onto UFR5 displayed the highest freezing tolerance, characterized by robust activation of antioxidant enzymes, elevated proline and glycine betaine accumulation, reduced oxidative damage, and sustained carbon–nitrogen metabolic fluxes under freezing stress. These results demonstrate that rootstock genotype governs the extent of scion defense activation and metabolic homeostasis under freezing conditions. Our findings identify UFR5 as a promising rootstock for enhancing freezing resilience in citrus and provide mechanistic insight into how scion–rootstock interaction orchestrates integrative stress tolerance pathways. Future work should focus on multi-omics dissection of rootstock-mediated signaling networks and long-term field validation to optimize rootstock selection for enhanced cold resilience under variable climatic conditions.

Functional roles of plant growth-promoting rhizobacteria in ungrafted and grafted watermelons under various deficit irrigation strategies

Abstract The global demand for natural rubber emphasizes the need for increasing yield per hectare as the expansion of planting areas becomes difficult. To overcome some of the limitations related to the propagation of rubber trees through grafting, research has been carried out for years on Hevea clonal plants produced by in vitro tissue culture technology (vitroplants, VP). This study conducts a large-scale evaluation of VP across two rubber estates in Ivory Coast and Ghana. Using VP could significantly reduce the growth time of seedlings in the nursery and provide flexibility in planting schedules independent of seed availability. For 66 months, 14 ha of field trials were monitored to compare growth dynamics, stand uniformity, and trunk conicity of VP with trees from grafted plants (GP) of RRIM600 clone. The findings reveal that VP exhibited superior trunk girth at 66 months, suggesting an earlier readiness for tapping compared to GP with a more conical trunk shape, which may lead to increased latex yield. The differences in growth rates in the field between VP and GP were significantly affected by the developmental stage of the plants at planting, with VP being planted with fully developed leaves and self-rooted systems, while GP were planted with developed rootstocks but dormant buds. This enabled VP to establish more rapidly and thus reach readiness for latex tapping sooner than GP. The study underscores the importance of further research on clonal selection, acclimatization period, rootstock interactions and the yield performances of this novel planting material.

Cyclocarya paliurus, endemic to the subtropical regions of southern China, holds significant potential as a health product, with its leaf-derived secondary metabolites commanding considerable value. This study aimed to investigate the secondary metabolites associated with graft success in C. paliurus by selecting three clones and three provenances as grafting scions and rootstocks. The survival rates of various graft combinations were meticulously recorded. Targeted metabolic profiling of the graft union was employed to analyze the flavonoid and phenylpropanoid biosynthesis pathways in both compatible and incompatible graft combinations. The results indicate that phenylpropanoids preferentially accumulate in compatible graft unions, while flavonoids are more abundant in incompatible unions. In the grafted seedlings of C. paliurus, ferulic acid, glycitein, dihydromyricetin, pinocembrin, and apigenin exhibited distinct accumulation patterns. These findings revealed the regulatory patterns within the phenylpropanoid biosynthesis pathway for predicting graft success in C. paliurus. The insights are valuable for the optimization of C. paliurus grafting practices and for future breeding programs aimed at enhancing the species’ horticultural and economic potential.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-12934-3.

BackgroundMicrografting technology has gained popularity in model plants, with the advantages of a wide grafting range and small space. However, this technique has not been fully explored in tea plants.ResultsIn our study, different rootstocks [radicle (obtained from the germination in seed), epicotyl without cotyledons, epicotyl with cotyledons, tea varieties] and scion (red branch, green branch) grafting combinations were used to estimate the survival rate, plant growth, the compatibility behavior, and cold tolerance of grafted seedlings. Our results showed that the higher survival rate and shooting rate were observed in radicle (obtained from the germinated seed diameter ≥ 15 mm, D3) as the rootstock. Also, the same growth indicators were found in the green branch as scion and radicle as rootstock (GB\\R) were higher than that of other grafting combinations. In addition, the grafted seedlings of LJ43 as rootstock had the best growth rate, and the vascular bundle bridge was completely established in SCZ as scion and LJ43 as rootstock (SCZ/LJ43) graft combination, accompanied with a higher survival rate, shoot rate and leaf number of new shoots and cold tolerance in field experiments.ConclusionOur findings provide a viable tea micrografting method, which has the potential to substitute traditional tea cuttings for tea seedling propagation and thus meet the requirements of tea cultivation.

Global climate change negatively affects life, thus complicating the production of vegetables. In addition to this, very little is known about eggplant cultivation under different irrigation strategies. For example, although water use efficiency gives better results in some plant species and varieties without any decrease in yield when the partial root drying (PRD) technique is used, the PRD technique has not been adequately examined in eggplant cultivation. The potential reactions of grafted and ungrafted eggplant plants under different irrigation water levels (100%, 80%, 60% and 40%) with the use of the conventional and deficit irrigation and PRD technique were investigated in this study. The research was conducted in a glass greenhouse during two cultivation seasons in 2019 and 2020. Irrigation was applied equally to both grafted and ungrafted eggplant plants using the drip irrigation method. In the study were examined the growth, quality criteria, yield, yield components, WUE, IWUE, and ky of eggplant to determine the reactions of grafted and ungrafted eggplant plants under different irrigation applications. It was found in the study that the method and amount of irrigation water applied had a significant effect on the grafted and ungrafted eggplant plants. Irrigation water was applied in the first and second season respectively between 148.45 and 365.48 mm, 245.61 and 584.84 mm. The statistical differences were found in the level of importance of yield, evapotranspiration, water-use efficiency, LSD classification of irrigation water-use efficiency values p<0.01 and/or p<0.05. Regression analysis values between irrigation water and yield of grafted and ungrafted eggplant in both cultivation seasons were found to be at a fairly good level (0.80<R2). In addition, as an important finding, the regression analysis value of grafting in the second season was found to be at the highest level (R2=91). In general, grafted eggplant plants were found to have had a higher total yield than the ungrafted plants. As the amount of irrigation water applied decreased, the yield also decreased. In the first season, the highest yields were recorded statistically in FPRD100, I100 and FPRD80 (45.26, 44.01 and 39.26 t ha-1, respectively). Similarly, in the second season, the highest yields were obtained in I100 and FPRD100 (50.97 and 48.96 t ha-1, respectively) followed by FPRD80 (48.96 t ha-1). The advantages of the PRD technique over conventional and deficit irrigation have also been revealed. As a result of the research, it could be recommended that the cultivation of grafted eggplant seedlings is more suitable, and irrigation applications could be carried out using the PRD technique.

In this experiment, wild-type Artemisia selengensis, Chrysanthemum, Artemisia annua and mugwort were used as rootstocks, while cultivated A. selengensis served as the scion. Cleft grafting was identified as the most effective method. The highest survival rate was observed when wild-type A. selengensis was used as the rootstock, reaching 92.5% on the 12th day post-grafting, with quicker callus formation than in other combinations. The combination of wild-type A. selengensis rootstock and cultivated A. selengensis scion demonstrated the greatest grafting compatibility, whereas the pairing of cultivated A. selengensis with chrysanthemum showed the lowest. During the healing phase, analysis revealed that in compatible graft combinations, soluble sugar levels increased, with a significant rise in soluble protein levels. Following callus formation, levels of superoxide dismutase (SOD), peroxidase (POD), and phenylalanine ammonia-lyase (PAL) declined. Hence, soluble sugars, SOD, POD, and PAL may act as indicators of grafting compatibility in A. selengensis. Weekly elongation measurements from 21 to 49 days post-grafting indicated that combinations rooted in chrysanthemum exhibited markedly greater elongation from 35 to 49 days than other pairs. Comparisons of soluble proteins, sugars, vitamin C, and flavonoids in the scion on days 49, 70, and 91 post-grafting with those in ungrafted plants suggested that different rootstocks differentially influenced nutrient and metabolite accumulation in A. selengensis. These findings suggest that future research could explore the mechanisms underlying these changes during the grafting process. Integrating molecular biology and metabolomics techniques will aid in elucidating specific regulatory mechanisms affected by grafting in Artemisia species, potentially enhancing the content of nutrients or bioactive compounds. This could provide theoretical support for biopharmaceutical applications and propose new methods for improving the quality of Artemisia germplasm resources.

BackgroundThis study is the first research to investigate the potential of grafting to induce tomato resistance to two-spotted spider mite (TSSM), Tetranychus urticae Koch. TSSM can cause up to 50% yield loss of tomato. The grafting technique permits the rapid adoption of biotic/abiotic stress resistance/tolerance from wild relatives as rootstock while preserving the scion’s important horticultural characteristics. Although TSSM resistance is found in wild tomato relatives, particularly those with the Mi-1 gene, its effects as rootstocks on TSSM resistance remain uncertain. Tomato ‘Nairouz F1’ (lacking Mi-1) grafted onto six interspecific hybrids with Solanum habrochiates (harboring Mi-1/mi-1), including commercial rootstock ‘Estamino’ and ‘Fortamino’, along with hybrids between tomato ‘VFN-14’ and each of S. habrochiates AusTRCF312064 (R312064), AusTRCF312344 (R312344), CGN15391 (R15391), and LA1777 (R1777). In the 2019 and 2020 fall seasons, the grafted and ungrafted plants were assessed in a naturally TSSM-infested field. The population of TSSM movable stages on grafted and ungrafted plants was estimated one week after transplanting, and every two weeks for 11 weeks. To assess antixenosis and antibiosis resistance in tomato grafts, TSSM males and females were reared on leaves of grafts onto R312064 and R15391, along with ungrafted plants. TSSM bio-behaviors and two-sex life table parameters were assessed.ResultsGrafting onto interspecific hybrids, particularly R15391, R312064, and R312344, significantly lowered TSSM populations compared to commercial rootstocks and ungrafted plants. HPLC analysis revealed that grafting induced foliar synthesis of herbivore-repellent (antixenosis) and antibiosis phenolics, viz., chlorogenic acid in all grafts and syringic acid, pyrocatechol, and vanillin in certain grafts. Grafts-R312064 showed delayed TSSM development, lower survival rates, lower fecundity, and higher mortality. Grafts-R312064 also had a longer mean generation time (GT; 23.33 days) and a lower reproductive rate (R0: 14.63), leading to a slower intrinsic population growth rate (rm: 0.115) compared to ungrafted plants and grafts-R15391.ConclusionThe findings suggest tomato grafting onto rootstocks with the Mi-1 gene, particularly R312064, could reduce TSSM populations through induced antixenosis and antibiosis resistance mechanisms.

Viruses alter the ecological and evolutionary trajectories of bacterial host communities. Plant grafting is a technique that integrates two species or varietiies and have consequences on the rhizosphere functioning. The grafting effects on the taxonomic and functional assembly of viruses and their bacterial host in the plant rhizosphere remain largely elusive. Using shotgun metagenome sequencing, we recover a total of 1441 viral operational taxonomic units from the rhizosphere of grafted and ungrafted plants after 8-year continuous monoculture. In the grafted and ungrafted rhizosphere, the Myoviridae, Zobellviridae and Kyanoviridae emerged as the predominant viral families, collectively representing around 40% of the viral community in each respective environment. Grafting enriched the members in viral family Kyanoviridae, Tectiviridae, Peduoviridae and Suoliviridae, and auxiliary metabolic genes related to pyruvate metabolism and energy acquisition (e.g., gloB, DNMT1 and dcyD). The virus-bacterial interactions increased the rapid growth potential of bacteria, which explains the strong increase in abundance of specific bacterial hosts (i.e., Chitinophagaceae, Cyclobacteriaceae and Spirosomaceae) in the grafted-plant rhizosphere. Overall, these results deepen our understanding of microbial community assembly and ecological services from the perspective of virus-host interactions.

Cassava brown streak disease (CBSD) remains the most severe threat to cassava production in the Great Lakes region and Southern Africa. Screening for virus resistance by subjecting cassava to high virus pressure in the epidemic zone (hotspots) is a common but lengthy process because of unpredictable and erratic virus infections requiring multiple seasons for disease evaluation. This study investigated the feasibility of graft-infections to provide a highly controlled infection process that is robust and reproducible to select and eliminate susceptible cassava at the early stages and to predict the resistance of adapted and economically valuable varieties. To achieve this, a collection of cassava germplasm from the Democratic Republic of Congo and a different set of breeding trials comprising two seed nurseries and one preliminary yield trial were established. The cassava varieties OBAMA and NAROCASS 1 infected with CBSD were planted one month after establishment of the main trials in a 50 m2 plot to serve as the source of the infection and to provide scions to graft approximately 1 ha. Grafted plants were inspected for virus symptoms and additionally tested by RT-qPCR for sensitive detection of the viruses. The incidence and severity of CBSD and cassava mosaic disease (CMD) symptoms were scored at different stages of plant growth and fresh root yield determined at harvesting. The results from the field experiments proved that graft-infection with infected plants showed rapid symptom development in susceptible cassava plants allowing instant exclusion of those lines from the next breeding cycle. High heritability, with values ranging from 0.63 to 0.97, was further recorded for leaf and root symptoms, respectively. Indeed, only a few cassava progenies were selected while clones DSC260 and two species of M. glaziovii (Glaziovii20210005 and Glaziovii20210006) showed resistance to CBSD. Taken together, grafting scions from infected cassava is a highly efficient and cost-effective method to infect cassava with CBSD even under rugged field conditions. It replaces an erratic infection process with a controlled method to ensure precise screening and selection for virus resistance. The clones identified as resistant could serve as elite donors for introgression, facilitating the transfer of resistance to CBSD.

The physicochemical properties of fruits at different maturity stages using grafting technology are of great importance since grafting can alter the nutritional and functional parameters of the fruit. In this study, grafted yellow pitahaya (Selenicereus megalanthus Haw.) fruit, grown on live tutors, was evaluated from stages 0 to 5. The following response variables were recorded: fruit weight, diameter, and length; pulp weight with seed and peel; color; firmness; total soluble solids content; titratable acidity; pH; total flavonoid content; total polyphenol content; and antioxidant activity determined using FRAP and ABTS. The results show that fruits harvested from grafted plants have better physical characteristics such as fruit weight, diameter, and length. However, the total soluble solids content and titratable acidity were similar in fruits from grafted and ungrafted plants. The highest content of total polyphenols, flavonoids, and antioxidant activity determined by ABTS and FRAP were found in fruits at maturity stage 0, and the content decreased as the fruits ripened. A positive correlation was found between the total polyphenol content, total flavonoid content, and antioxidant capacity with protein content. The S. megalanthus grafting technique is a promising technology for sustainable production because it reduces pesticide use by combatting soil pathogens and not modifying fruit quality.

Sharka disease, caused by the plum pox virus (PPV), negatively impacts stone fruit production, resulting in economic losses. It has been demonstrated that grafting the almond (Prunus dulcis (Miller) D.A. Webb) variety ‘Garrigues’ into susceptible peach (Prunus persica (L.) Batsch) rootstocks can result in PPV resistance. The molecular circuits related to grafting in Prunus species, however, have not been fully investigated. In this study, susceptible peach rootstocks ‘GF305’ were either heterografted with ‘Garrigues’ almond or homografted with the same cultivar. Peach samples were collected at two stages of scion development, with ungrafted plants utilized as controls. Profiles of transcripts, small RNAs (sRNAs), and DNA methylation were obtained and analyzed on a genome-wide scale. Homografting and heterografting significantly altered the transcriptome and methylome of peach rootstocks, with these modifications being more pronounced during the early stages of scion development. The profiles of sRNAs were significantly more impacted when almonds were used as a scion as opposed to peaches, likely due to the transmission of PPV-unrelated viral sequences. Gene expression differences resulting from DNA methylation alterations are more thoroughly documented at the promoter sequences of genes than within their bodies. This study suggests that the ‘Garrigues’ almond variety triggers a complex defense response in the peach rootstock, potentially involving the interplay of epigenetic modifications and small RNA-mediated priming of antiviral defenses, which ultimately may contribute to PPV resistance.

Watermelon is an important fruit widely cultivated in tropical and temperate regions across the world. Particularly in China, both the production and consumption of watermelon lead the world. Watermelon is popular all over the world because it is rich in a variety of nutrients. Despite its widespread appeal, watermelon cultivation is frequently challenged by biological and abiotic stresses, which can significantly impair both yield and fruit quality. Grafting is a technique known to enhance the yield and quality of watermelons, yet the identification of suitable rootstocks and a comprehensive understanding of the cytological, physiological, and biochemical aspects of grafting remain elusive. In this study, we had identified the ‘Heiniu’ pumpkin variety as the optimal rootstock for watermelon grafting. Furthermore, we had determined that the most appropriate stages for scion and rootstock grafting are the one-true-leaf stage and the two-true-leaf stage, respectively. During the grafting process, the necrotic layer of the graft junction gradually dissipated, facilitating a tight connection between the scion and rootstock. Concurrently, there was a notable fluctuation in the levels of key plant hormones and protease activity throughout the healing process of the graft union, suggesting that these factors were pivotal to the success of watermelon grafting. Additionally, our findings indicated that grafting can significantly increase the sugar and titratable acid content within watermelons. This research contributes to a deeper comprehension of the histological and physiological mechanisms underlying watermelon grafting. It offers both theoretical insights and practical guidance essential for the advancement of watermelon grafting techniques.

BackgroundPlant-soil feedback arises from microbial legacies left by plants in the soil. Grafting is a common technique used to prevent yield declines in monocultures. Yet, our understanding of how grafting alters the composition of soil microbiota and how these changes affect subsequent crop performance remains limited. Our experiment involved monoculturing ungrafted and grafted watermelons to obtain conditioned soils, followed by growing the watermelons on the conditioned soils to investigate plant-soil feedback effects.ResultsUngrafted plants grew better in soil previously conditioned by a different plant (heterospecific soil) while grafted plants grew better in soil conditioned by the same plant (conspecific soil). We demonstrated experimentally that these differences in growth were linked to changes in microorganisms. Using a supervised machine learning algorithm, we showed that differences in the relative abundance of certain genera, such as Rhizobium, Chryseobacterium, Fusarium, and Aspergillus, significantly influenced the conspecific plant-soil feedback. Metabolomic analyses revealed that ungrafted plants in heterospecific soil enriched arginine biosynthesis, whereas grafted plants in conspecific soil increased sphingolipid metabolism. Elsewhere, the metagenome-assembled genomes (MAGs) of ungrafted plants identified in heterospecific soil include Chryseobacterium and Lysobacter, microorganisms having been prominently identified in earlier research as contributors to plant growth. Metabolic reconstruction revealed the putative ability of Chryseobacterium to convert D-glucono-1,5-lactone to gluconic acid, pointing to distinct disease-suppressive mechanisms and hence distinct microbial functional legacies between grafted and ungrafted plants.ConclusionsOur findings show a deep impact of the soil microbial reservoir on plant growth and suggest the necessity to protect and improve this microbial community in agricultural soils. The work also suggests possibilities of optimizing microbiota-mediated benefits through grafting herein, a way that “engineered” soil microbial communities for better plant growth.BP591-gZtAk87jMPWFVThJVideo

Recently, there has been growing interest in plant-inspired materials for various biological, medical, and industrial applications. Notably, tannic acid-based materials exhibit remarkable adhesive properties and can be used in a variety of applications, particularly biomedical applications. In addition, mixtures composed of tannic acid and polymers (e.g., polyvinyl alcohol) exhibit excellent adhesion to various substrates. In this study, we developed gallol-containing chitosan (G-CS), polyvinyl alcohol (PVA), and tannic acid (TA) composite (G-CPT) hydrogels as wood adhesive materials. G-CPT hydrogels were immediately formed by mixing the G-CS/PVA solution with the TA solution. Rheological analysis revealed an increase in the elastic modulus (G′) with the addition of small amounts of G-CS. In addition, the detachment stress of wood sticks attached using G-CPT hydrogels was 142.2 ± 7.2 MPa, which was substantially higher than that of G-CS (5.3 ± 1.4 kPa), PVA (2.2 ± 0.2 kPa), TA (0.4 ± 0.1 kPa), and PVA/TA hydrogels (106.5 ± 2.5 MPa). Furthermore, G-CPT hydrogels can be used as wood adhesives for scion grafting into the rootstock of English ivy. These findings highlight the importance of G-CPT hydrogels as eco-friendly wood adhesives with enormous potential for various industrial and agricultural applications.

IntroductionSpecies of Botryosphaeriaceae fungi are relevant pathogens of almond causing trunk cankers, extensive gumming, necrosis of internal tissues and plant dieback and dead, threatening almond productivity. A novel triplex quantitative real-time PCR (qPCR) assay was designed for the simultaneous detection and quantification of Neofusicoccum parvum, Botryosphaeria dothidea and the Botryosphaeriaceae family.Material and methodsThe method was validated in symptomatic and asymptomatic almond, avocado, blueberry and grapevine plants and in environmental samples, such as cropping soil and rainwater and in artificially inoculated trapped spores, demonstrating the same performance on several matrices.Results and discussionThe limit of detection of the triplex qPCR was 10 fg of genomic DNA for the three fungal targets, with high correlation coefficients (R2) and amplification efficiencies between 90 and 120%. Although the triplex qPCR demonstrated to be more sensitive and accurate than the traditional plate culturing and further sequencing method, a substantial agreement (kappa index = 0.8052 ± 0.0512) was found between the two detection methods. The highly sensitive qPCR assay allows for accurate diagnosis of symptomatic plants and early detection of Botryosphaeriaceae fungi in asymptomatic plants (rootstocks and grafting scions from almond nurseries). Furthermore, the triplex qPCR successfully detected Botryosphaeriaceae fungi in environmental samples, such as cropping soils and rainwater. It was also capable of detecting as few as 10 conidia in artificially inoculated tapes. Therefore, the triplex qPCR is a valuable tool for accurate diagnosis, aiding in the implementation of suitable control measures. It enables preventive detection in asymptomatic samples, helping to avoid the introduction and spread of these pathogens in production fields. Moreover, it assists in identifying inoculum sources and quantifying inoculum levels in crop environments, contributing to a precise phytosanitary application schedule, thereby reducing production costs and preserving the environment.

Plants recruit microorganisms from bulk soil by secreting easily available organic carbon into the rhizosphere. Grafting often increases the disease resistance of agricultural plants by modifying this carbon flow from roots into rhizosphere and by recruiting active microorganisms that suppress pathogens. Here, we continuously labeled grafted and ungrafted watermelon plants in a 13CO2 atmosphere to identify the active microorganisms assimilating root exudates. Multi-omics associated technologies (amplicon sequencing, metagenomics and metabolomics) combined with 13C tracing were used to examine the carbon flows, microbial utilization and transformation in the rhizosphere. The number of potentially active bacterial species recruited in the rhizosphere of grafted plants and utilizing root exudates was four times more than in ungrafted plants. These potentially active species matched to metagenome-assembled-genomes (MAGs) mainly belonging to Sphingomonas in the rhizosphere of ungrafted plants, and to Sphingomonas, Chitinophaga, Dyadobacter and Pseudoxanthomonas in the rhizosphere of grafted plants. Sphingomonas possesses the functional potential to metabolize a plant self-toxic substance, namely 4-hydroxybenzoic acid. Furthermore, grafting shaped the complex metabolic interactions and changed the original metabolic dependence between the potentially active bacterial species. Grafting plants diversified belowground carbon flows, activating a greater number of beneficial microbes.