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The study aims to investigate at a physiological and molecular level the root absorption of nitrogen (N) during the annual cycle of grapevine. The study was performed on potted Pinot Gris plants grafted on Kober 5BB and grown for two consecutive years in a semi-controlled environment (Northeast, Italy). The study compared the response of plants N-fertilized in spring (T1), or in spring and in post-harvest (T2) or no-N fertilized (C). Results showed that under our climate conditions nitrate was taken up by the grapevines when applied both in spring or in spring and post-harvest. The nitrate acquisition in T1 roots is mediated at molecular and physiological level by a higher activation of high-affinity nitrate-transport system to take up nitrate in comparison to no-fertilized plants. Comparing the two N fertilization managements, the dynamic of nitrate uptake rates showed different patterns with an overall late response of High-Affinity Transport System when the application of part of N-fertilization was delayed to post-harvest (T2) in comparison to T1. Nevertheless, during the 2 years of the trial the fractionation of N fertilization applied in spring and post-harvest did not negatively affect the yield and quality parameters of vines. An increase of N concentration in T2 roots after two consecutive growing seasons may suggest that the fractionation can lead to beneficial effects on long period. Results of this work contribute to improve the comprehension of N acquisition in grapevine in order to optimize the use of N inputs in vineyard.

The importance of plants as complex entities influenced by genomes of the associated microorganisms is now seen as a new source of variability for a more sustainable agriculture, also in the light of ongoing climate change. For this reason, we investigated through metatranscriptomics whether the taxa profile and behaviour of microbial communities associated with the wood of 20-year-old grapevine plants are influenced by the health status of the host. We report for the first time a metatranscriptome from a complex tissue in a real environment, highlighting that this approach is able to define the microbial community better than referenced transcriptomic approaches. In parallel, the use of total RNA enabled the identification of bacterial taxa in healthy samples that, once isolated from the original wood tissue, displayed potential biocontrol activities against a wood-degrading fungal taxon. Furthermore, we revealed an unprecedented high number of new viral entities (~120 new viral species among 180 identified) associated with a single and limited environment and with potential impact on the whole holobiont. Taken together, our results suggest a complex multitrophic interaction in which the viral community also plays a crucial role in raising new ecological questions for the exploitation of microbial-assisted sustainable agriculture.

"Grapevine performance under drought largely depends on the varietal physiological and hydraulic strategies adopted in response to water stress. In this study we aimed to characterize the main ecophysiological traits of 'Glera' wine grape variety, for which no studies on water relations and ABA dynamics have so far been reported. Potted 'Glera' plants were subjected to prolonged mild and severe water stress conditions and compared with control plants. The course of leaf gas exchange, stem water potential (Wstem) and leaf ABA concentration were followed during the stress imposition and the rehydration processes. Yield and quality parameters were also measured at harvest. 'Glera' subjected to both severe and mild stress showed decreased leaf gas exchange, Wstem, agronomic and quality parameters. This was particularly evident in the severe stress, where net photosynthesis decreased progressively to zero due to significant stomatal limitation and it did not fully recover after rehydration. Agronomic and berry quality features measured at harvest did not recover either. In both stress treatments leaf ABA concentration increased only after stomatal closure and, for severe drought, ABA remained at high concentration till one day after re-watering. Re-watered plants quickly recovered Wstem while stomatal conductance gradually increased only when leaf ABA concentration decreased. In the present study, stomatal limitation was hydraulic dependent, while the decrease in leaf ABA concentration following re-watering was associated with gradual recovery of leaf gas exchange"

Domestication processes, amplified by breeding programs, have allowed the selection of more productive genotypes and more suitable crop lines capable of coping with the changing climate. Notwithstanding these advancements, the impact of plant breeding on the ecology of plant-microbiome interactions has not been adequately considered yet. This includes the possible exploitation of beneficial plant-microbe interactions to develop crops with improved performance and better adaptability to any environmental scenario. Here we discuss the exploitation of customized synthetic microbial communities in agricultural systems to develop more sustainable breeding strategies based on the implementation of multiple interactions between plants and their beneficial associated microorganisms.

Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae), the brown marmorated stink bug, is an invasive pentatomid native to East-Asia, and introduced worldwide in recent times. It is a polyphagous pest with approximately 300 host plants, which, due to its plasticity, reproductive and feeding behavior, long-distance flight, and walking as well as human-mediated dispersal ability, is able to cause significant economic and ecological damage. In several cases pest control mediated by insecticide treatments leads to unsatisfactory efficacy, mostly due to insect recovery ability. Thus, the most promising method for the long-term management of this pest has been focused with growing emphasis on classical biological control strategies. In this framework, viruses have untill now been poorly investigated in H. halys with only a single virus described from the US territory. For this reason we investigated the virome associated with a small and well described population of H. halys from Piedmont (Italy) describing for the first time 7 new viral sequences belonging to different taxonomical groups. Further studies will be necessary to assess the biological and ecological effects the viruses have on their host. Due to the agricultural importance of this insect, the biological characterization of these viruses would give important information on the possibility to exploit viral entities as biological control agents. Finally, the presence of a such relevant number of viruses from a small population suggests a wide association between the brown marmorated stink bug and viral entities. Further studies to determine the possible exploitation of viral sequences to trace different populations are ongoing.

In this study, we analysed a total of 16 libraries from over 150 grapevine leaf and grape samples infected with Plasmopara viticola (downy mildew of grapevine) to characterise the virome associated to this oomycete. Samples were collected in five distinct regions in Italy and in four different regions in Spain, representative of different pedoclimatic conditions and different grapevine cultivars during 2018 growing season. Due to the metagenomics nature of the samples (containing at least both downy mildew hyphae and spores, and grapevine cells residues), we were able to assemble several plant viruses and a few possible novel plant virus genomes with our in silico analysis. We detected several plant virus variants already reported in grapevine, and a putative new ilarvirus previously unreported in grapevine. Furthermore, we characterised three new phenui-like viruses (in the order Bunyavirales), one of which shares some commonalities with plant coguviruses. Finally, we report a new strict association of three viral segments (one flavi-like and two virga-like) that we propose to be a new virus taxon named jivivirus.

Reduction of fungicide consumption in agriculture is globally recognized as a priority. Government authorities are fostering research to achieve a reduction of risks associated with conventional pesticides and promoting the development of sustainable alternatives. To address these issues, in the present study, alternative protocols for the control of downy mildew infection in grapevine were compared to the standard protocol. In the first protocol, only resistance inducers were used, comprising a single formulation with Acibenzolar S-methyl, laminarin and disodium-phosphonate. The second and third protocols followed the standard protocol but substituted phosphonates with phosphorus pentoxide and Ecklonia maxima extract.The results showed that at veraison downy mildew incidence and severity in all tested protocols were significantly reduced compared to nontreated controls on both canopy and bunches. Expression analysis of key genes involved in plant stress response, indicated that the two protocols for phosphites substitution induced a remodulation of salicylic acid (SA) and jasmonic acid (JA), with positive impact on yields. Analysis of the first protocol revealed that the primed state induced a short delay in bunch ripening, with a shift of carbohydrate metabolism to boost the plant defences, involving an upregulation of defence related-gene, SAR response and a decreased ROS detoxification. Additionally, analysis on the arthropods populations, in parallel with the positive results achieved using alternatives to conventional fungicides, were enriched by those showing the potential of naturally occurring predators of spider mites.This study provides practical solutions to reduce the environmental impact of treatments for the control downy mildew in viticulture. © 2022 Society of Chemical Industry.

Viruses can interfere with the ability of plants to overcome abiotic stresses, indicating the existence of common molecular networks that regulate stress responses. A begomovirus causing the tomato yellow leaf curl disease was recently shown to enhance heat tolerance in tomato and drought tolerance in tomato and Nicotiana benthamiana and experimental evidence suggested that the virus-encoded protein C4 is the main trigger of drought responses. However, the physiological and molecular events underlying C4-induced drought tolerance need further elucidation. In this study, transgenic tomato plants expressing the tomato yellow leaf curl Sardinia virus (TYLCSV) C4 protein were subjected to severe drought stress, followed by recovery. Morphometric parameters, water potential, gas exchanges, and hormone contents in leaves were measured, in combination with molecular analysis of candidate genes involved in stress response and hormone metabolism. Collected data proved that the expression of TYLCSV C4 positively affected the ability of transgenic plants to tolerate water stress, by delaying the onset of stress-related features, improving the plant water use efficiency and facilitating a rapid post-rehydration recovery. In addition, we demonstrated that specific anatomical and hydraulic traits, rather than biochemical signals, are the keynote of the C4-associated stress resilience. Our results provide novel insights into the biology underpinning drought tolerance in TYLCSV C4-expressing tomato plants, paving the way for further deepening the mechanism through which such proteins tune the plant-virus interaction.

Nowadays, the worldwide agriculture is experiencing a transition process toward more sustainable production, which requires the reduction of chemical inputs and the preservation of microbiomes’ richness and biodiversity. Plants are no longer considered as standalone entities, and the future of agriculture should be grounded on the study of plant-associated microorganisms and all their potentiality. Moreover, due to the climate change scenario and the resulting rising incidence of abiotic stresses, an innovative and environmentally friendly technique in agroecosystem management is required to support plants in facing hostile environments. Plant-associated microorganisms have shown a great attitude as a promising tool to improve agriculture sustainability and to deal with harsh environments. Several studies were carried out in recent years looking for some beneficial plant-associated microbes and, on the basis of them, it is evident that Actinomycetes and arbuscular mycorrhizal fungi (AMF) have shown a considerable number of positive effects on plants’ fitness and health. Given the potential of these microorganisms and the effects of climate change, this review will be focused on their ability to support the plant during the interaction with abiotic stresses and on multi-omics techniques which can support researchers in unearthing the hidden world of plant–microbiome interactions. These associated microorganisms can increase plants’ endurance of abiotic stresses through several mechanisms, such as growth-promoting traits or priming-mediated stress tolerance. Using a multi-omics approach, it will be possible to deepen these mechanisms and the dynamic of belowground microbiomes, gaining fundamental information to exploit them as staunch allies and innovative weapons against crop abiotic enemies threatening crops in the ongoing global climate change context.

Along with the ongoing climate change, drought events are predicted to become more severe. In this context, the Spray Induced Gene Silencing (SIGS) technique could represent a useful strategy to improve crop stress resilience. A previous study demonstrated that the Arabidopsis mutants for a glutathione S-transferase (GST) gene had increased abscisic acid (ABA) levels and a more activated anti-oxidant system, both features that improved drought resilience. Here, we used SIGS to target a putative grape GST gene (VvGST40). Then, ecophysiological, biochemical and molecular responses of 'Chardonnay' cuttings were analysed during a drought and recovery time-course. Gas exchange, ABA and t-resveratrol concentration as well as expression of stress-related genes were monitored in not treated controls, dsRNA-VvGST40- and dsRNA-GFP- (negative control of the technique) treated plants, either submitted or not to drought. VvGST40-treated plants revealed increased resilience to severe drought as attested by the ecophysiological data. Analysis of target metabolites and antioxidant- and ABA-related transcripts confirmed that VvGST40-treated plants were in a priming status compared with controls. SIGS targeting an endogenous gene was successfully applied in grapevine, confirming the ability of this technique to be exploited not only for plant protection issues but also for functional genomic studies. This article is protected by copyright. All rights reserved.

Microbial multi-level interactions are essential to control the success of spreading and survival of most microbes in natural environments. Phytopathogenic mycotoxigenic fungal species, such as Aspergillus flavus, represent an important issue in food safety. Usually, non-toxigenic strains are exploited for biocontrol strategies to mitigate infections by toxigenic strains. To comprehend all the biological variables involved in the aflatoxin biosynthesis, and to possibly evaluate the interplay between A. flavus toxigenic and non-toxigenic strains during intraspecific biocompetition, the “virological” perspective should be considered. For these reasons, investigations on mycoviruses associated to A. flavus populations inhabiting specific agroecosystems are highly desirable. Here, we provide the first accurate characterization of the novel mycovirome identified within an A. flavus wild population colonizing the maize fields of northern Italy: a selection of A. flavus strains was biologically characterized and subjected to RNAseq analysis, revealing new mycoviruses and a peculiar geographic pattern distribution in addition to a 20% rate of infection. More interestingly, a negative correlation between viral infection and aflatoxin production was found. Results significantly expanded the limited existent data about mycoviruses in wild A. flavus, opening new and intriguing hypotheses about the ecological significance of mycoviruses.

The common chameleonChamaeleochamaeleonis a Mediterranean lizard which has been introduced in many islands and its native origin in European countries is debated. Chameleons have been introduced in southern Italy, possibly from the Middle East and Tunisia. We conducted genetic analyses on mitochondrial DNA 16S gene on a larger sample. We observed a multiple origin for the Salento (Apulia, southern Italy) population, with individuals phylogenetically related to populations of North Africa and two areas in the Middle East. Some individuals may have been released before the 1950s and some others in the 1980s, improving the establishment success of this species.

Among invasive squirrels in Europe, the Siberian chipmunk Eutamias sibiricus, native to North-East Asia, shows the highest number of free-ranging populations in European countries, due to the intense pet trade it underwent between the 1960s and the 1980s. We describe 628-bp cytochrome b sequences from the Netherlands (N = 3), Belgium (N = 4) and Switzerland (N = 1), and through phylogenetic analysis show that they belong to the Korean subspecies. This confirms previous findings that the Korean subspecies (Eutamias sibiricus barberi) has been the most commonly introduced to Europe. Another subspecies (the Northern subspecies, Eutamias sibiricus sibiricus) has only been reported previously in an Italian free-living population. If the splitting of the Korean taxon as a proper species (Eutamias barberi) will be confirmed by analysis of nuclear markers, a revision of the European Regulation 1143/2014 should be conducted to explicitly ban the trade of newly identified taxa., Support to MM for this research (grant LCF/BQ/DR20/11790020) was provided by ‘La Caixa’ Foundation (ID 100010434).

Aims: Soil microbiome roles in agriculture is becoming more and more important. This importance is also reflected on the way plants are seen: complex organisms formed by the plant itself plus the microbes inhabiting its tissues, including the ones on the surface of every organ and the ones adhered or in proximity to the roots. In addition, as already demonstrated, the microbial community associated with a specific soil is able to predetermine the health status of crops. For all the above mentioned reasons, defining the microbial composition of agricultural soils and the factors driving the assemblage is pivotal to achieve more sustainable agriculture and viticulture. Methods: We aimed to investigate how the soil geological characteristics influence the microbiome composition associated with close geographically related vineyards. Moreover, we studied both the top (15 cm in depth) and deep (120 cm in depth) soil layers as anthropically influenced and almost-undisturbed soil, respectively. Results: We observed slightly different microbial communities despite the close geographical proximity of the two vineyards, which is considered one of the main determinants of the soil microbiome composition. In addition, we found that the geological characteristics of the two soils influence both the root distribution and the accumulation of pathogen- and symbiont-related genera. Sensory profiles of the Grillo wines from the two different soils confirmed the tight link between soil origin and wine traits. Conclusions: In the present study, we highlight that the geological characteristics of soil can influence soil microbial composition and assemblage in close geographically related vineyards, with a potential effect on wine features.

It is well known that AM symbiosis provides several ecosystem services leading to plant adaptation in different environmental conditions and positively affects physiological and production features. Although beneficial effects from grapevine and AM fungi interactions have been reported, the impact on growth-defence tradeoff features has still to be elucidated. In this study, the potential benefits of an inoculum formed by two AM fungal species, with or without a monosaccharide addition, were evaluated on young grapevine cuttings grafted onto 1103P and SO4 rootstocks. Inoculated and non-inoculated plants were maintained in potted vineyard substrate under greenhouse conditions for 3 months. Here, agronomic features were combined with biochemical and molecular techniques to assess the influence of the different treatments. Despite the opposite behaviour of the two selected rootstocks, in AM samples, the evaluation of gene expression, agronomic traits and metabolites production revealed an involvement of the whole root microbiome in the growth-defence tradeoff balancing. Noteworthy, we showed that rootstock genotypes and treatments shaped the root-associated microbes, stimulating plant growth and defence pathways. Progresses in this field would open new perspectives, enabling the application of AMF or their inducers to achieve a more sustainable agriculture also in light of the ongoing climate change.

Background The role of soil microbiomes in agriculture is now becoming more and more important, leading to definition of plants as complex organisms formed by the plant itself plus the microbes inhabiting its tissues, the surface of every organ and the ones living adhered or in proximity of the roots. In this context it is important to define the factors able to influence the composition of such microbial communities. In addition, as already demonstrated, the microbial community associated to a specific soil is able to predetermine the health status of the crops in the future. For this reason, we decided to investigate how the soil geological characteristics can influence the microbial community associated to the close geographical related vineyard.Results We decided to analyse a calcarenitic and a marly-limestone soil which are both typical of the viticulture in the Menfi area (Sicily, Italy). Moreover, since vineyard is a semi-anthropic environment we decided to investigate both the top (10-20 cm) and deep (120 cm) soil layers as anthropic influenced and almost-undisturbed soil respectively. Interestingly we observed that, despite the close geographical proximity, the soil microbiomes were slightly different and that in addition, the soil geological characteristics are able to influence the root distribution and the accumulation of both pathogen- and symbiont-related genera. Furthermore, sensory profiles of the Grillo wines obtained from the two different soils confirmed the tight link between soil origin and wine traits.Conclusions In contrast to what observed in other works we pointed out that the geological characteristics of soils can have an important influence on soil microbial composition and assemblage in close geographical related vineyards, with a potential effect on wine features. Furthermore, defining the microbial composition of agricultural soils it’s a crucial step to achieve a more sustainable agriculture and viticulture. In this optic, the observed link between the geological characteristics and the microbiome profiles need to be taken into account when considering a soil for the successful establishment low chemical input agriculture practices.The SRA accession numbers of the NGS reported in this paper are deposited in NCBI under the BioProject PRJNA655455; BioSample SAMN15735114 and SAMN15735115; SRA accession SRR12436974 and SRR12436973

Trigonella foenum-graecum (fenugreek) is a leguminous plant that produces secondary metabolites frequently used in medicinal and food preparation. Here, the role of an arbuscular mycorrhizal (AM) fungal inoculum, alone or in combination with methyl jasmonate (MeJA) chemical treatment, was evaluated on the production of trigonelline and diosgenin in fenugreek plants grown under mild water limitation. After inoculation, fenugreek plants were subjected to several combined treatments, i.e. well-watered (NS) and water-stressed (WS), both treated with different MeJA concentrations (0, 50, 100, 200 mL/L). At the end of the experiment, in addition to trigonelline and diosgenin content, an array of plant growth parameters (i.e. fruit, stem and root dry weights, fruit number) and biochemical stress markers (i.e. proline, nitric oxide, hydrogen peroxide, MDA) were examined. Results mainly showed a significant increase in production of the considered secondary metabolites, although they are differentially influenced by the individual factors (Stress, SYM, MeJA) and their interactions. SYM treatment was more effective on the production of trigonelline, independently from growth conditions, while diosgenin biosynthesis was influenced by the presence of root symbioses only in combination with MeJA treatment. A differential impact, depending on the applied treatment (inoculum, MeJA treatments, water deficit), on plant growth and on production of the considered bioactive molecules was revealed, providing new information on the effect of biological and chemical priming treatments.

The family Botourmiaviridae includes viruses infecting plants and filamentous fungi containing a positive-sense, ssRNA genome that can be mono- or multi-segmented. Genera in the family include: Ourmiavirus (plant viruses), and Botoulivirus, Magoulivirus and Scleroulivirus (fungal viruses). This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the family Botourmiaviridae, which is available at ictv.global/report/botourmiaviridae.

Several recent reports have highlighted some of the mechanisms involved in the enhanced tolerance to abiotic stresses induced by root-associated microorganisms, although additional efforts are still required to exploit and optimize these strategies. Particularly, arbuscular mycorrhizal fungi (AMF) play an important role as &ldquo, bio-fertilizing microorganisms&rdquo, establishing mutualistic symbioses with the roots of most crops. In this work, different microbial inocula (a single AMF species, a combination of three different AMF species, a combination of two plant growth-promoting bacteria (PGPB) strains and a more complex commercial inoculum) have been used to inoculate tomato plants (cv San Marzano nano), in order to verify their effects on the tolerance to a water deficit condition in pots, through the evaluation of biochemical stress markers and hormonal profiles (ABA and IAA). Results showed differences among tomato responses to water limitation depending on microbial inocula, confirming the importance to characterize the optimal plant/microorganism genotype combination(s) to maximize plant performance and tolerance. These findings open new perspectives for a better exploitation of these microorganisms.

Over a long time, the ongoing global changing scenario has led to increase temperature levels and CO2 concentration that in turn influenced the severity and frequency of biotic and abiotic stresses threatening agricultural productivity and food security. These stressors, destined to increase in the future, are one of the main challenges that researchers are dealing with by developing sustainable strategies to enhance crops resilience. During the last decade, the “primed” physiological state has attracted increasing attention since primed-plants are able to display faster and stronger defense responses. That state can be reached following treatments with various inducers such as chemical compounds or beneficial microbes. Although this phenomenon was discovered a long time ago, new perspectives are still coming up. In this context, recent reports on beneficial plant-virus interactions, the possibility to exploit the innate plant silencing pathway using double stranded RNAs (dsRNAs), and the increasing understanding of defense priming mechanisms are pushing research toward new sustainable frontiers.

Molecular changes associated with response to powdery mildew (PM) caused by Erysiphe necator have been largely explored in Vitis vinifera cultivars, but little is known on transcriptional and metabolic modifications following application of resistance elicitors against this disease. In this study, the whole transcriptome sequencing, and hormone and metabolite analyses were combined to dissect long-term defense mechanisms induced by molecular reprogramming events in PM-infected &lsquo, Moscato&rsquo, and &lsquo, Nebbiolo&rsquo, leaves treated with three resistance inducers: acibenzolar-S-methyl, potassium phosphonate, and laminarin. Although all compounds were effective in counteracting the disease, acibenzolar-S-methyl caused the most intense transcriptional modifications in both cultivars. These involved a strong down-regulation of photosynthesis and energy metabolism and changes in carbohydrate accumulation and partitioning that most likely shifted the plant growth-defense trade-off towards the establishment of disease resistance processes. It was also shown that genotype-associated metabolic signals significantly affected the cultivar defense machinery. Indeed, &lsquo, built up different defense strategies, often enhanced by the application of a specific elicitor, which resulted in either reinforcement of early defense mechanisms (e.g., epicuticular wax deposition and overexpression of pathogenesis-related genes in &lsquo, ), or accumulation of endogenous hormones and antimicrobial compounds (e.g., high content of abscisic acid, jasmonic acid, and viniferin in &lsquo, ).

Tomato plants can establish symbiotic interactions with arbuscular mycorrhizal fungi (AMF) able to promote plant nutrition and prime systemic plant defenses against pathogens attack, the mechanism involved is known as mycorrhiza-induced resistance (MIR). However, studies on the effect of AMF on viral infection, still limited and not conclusive, indicate that AMF colonization may have a detrimental effect on plant defenses against viruses, so that the term &ldquo, mycorrhiza-induced susceptibility&rdquo, (MIS) has been proposed for these cases. To expand the case studies to a not yet tested viral family, that is, Bromoviridae, we investigated the effect of the colonization by the AMF Funneliformis mosseae on cucumber mosaic virus (CMV) infection in tomato by phenotypic, physiological, biochemical, and transcriptional analyses. Our results showed that the establishment of a functional AM symbiosis is able to limit symptoms development. Physiological and transcriptomic data highlighted that AMF mitigates the drastic downregulation of photosynthesis-related genes and the reduction of photosynthetic CO2 assimilation rate caused by CMV infection. In parallel, an increase of salicylic acid level and a modulation of reactive oxygen species (ROS)-related genes, toward a limitation of ROS accumulation, was specifically observed in CMV-infected mycorrhizal plants. Overall, our data indicate that the AM symbiosis influences the development of CMV infection in tomato plants and exerts a priming effect able to enhance tolerance to viral infection.