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Tuber melanosporum is an ascomycete that forms ectomycorrhizal (ECM) symbioses with a wide range of host plants, producing edible fruiting bodies with high economic value. The quality of seedlings in the early symbiotic stage is important for successful truffle cultivation. Numerous bacterial species have been reported to take part in the truffle biological cycle and influence the establishment of roots symbiosis in plant hosts and the development of the carpophore. In this work, three different bacteria formulations were co-inoculated in Quercus ilex L. seedlings two months after T. melanosporum inoculation. At four months of bacterial application, the T. melanosporum ECM root tip rate of colonization and bacterial presence were assessed using both morphological and molecular techniques. A 2.5-fold increase in ECM colonization rate was found in the presence of Pseudomonas sp. compared to the seedlings inoculated only with T. melanosporum. The same treatment caused reduced plant growth either for the aerial and root part. Meanwhile, the ECM colonization combined with Bradyrhizobium sp. and Pseudomonas sp. + Bradyrhizobium sp. reduced the relative density of fibrous roots (nutrient absorption). Our work suggests that the role of bacteria in the early symbiotic stages of ECM colonization involves both the mycorrhizal symbiosis rate and plant root development processes, both essential for improve the quality of truffle-inoculated seedlings produced in commercial nurseries. [ABSTRACT FROM AUTHOR]

Fungicides are usually applied on strawberries to manage gray mold, induced by the fungal pathogen Botrytis cinerea. In this study, four reduced-risk fungicides (formulations of pyrimethanil, PYR, 175 mL/hL; boscalid, BOS, 80 g/hL; combination fludioxonil, FLU, +cyprodinil, CYP, 110 g/hL) were applied before harvest for the management of post-harvest diseases of strawberries. The resulting fungicide residues on the strawberry fruit were also quantified. Strawberry fruits were harvested at 0, 4, 8, and 12 days following treatment (dft) and kept at 20 ± 1 °C for 4 days or cold-stored for 7 days at 0.5 ± 1 °C, followed by a 4-day shelf life at 20 ± 1 °C. All fungicides significantly reduced gray mold, according to the McKinney Index. At 0 dft and 4 days of shelf life, the FLU + CYP completely prevented post-harvest strawberry gray mold, while PYR and BOS reduced the disease by 88% and 42%, respectively, in comparison to the untreated control. For the duration of experiment, fungicide residues were always below the maximum residue levels, and FLU was the most degraded, thanks to the enzymatic pool of the strawberries. Monitoring fungicide residues in strawberries is essential to provide the consumer information on the safety of this widely consumed fruit. The present study points out the safety of strawberry fruits for consumers, even if the treatment strategy implies the use of fungicide mixtures before the consumption, with fungicide levels always being below the MRL. [ABSTRACT FROM AUTHOR]

Use of novel alternative compounds in agriculture is being promoted to reduce synthetic pesticides. An in vitro study was conducted to evaluate antimicrobial and antioxidant activities of chitosan hydrochloride (CH) and COS (chito-oligosaccharides)-OGA (oligo-galacturonides) at concentrations of 1%, 0.5%, 0.25%, 0.1%, 0.05%, and 0.025%. COS-OGA at 1% and 0.5% concentrations completely inhibited mycelial growth of Alternaria alternata, Alternaria brassicicola, Botrytis cinerea, Monilinia laxa, Monilinia fructigena, and Monilinia fructicola. Further, complete inhibition was observed with 0.25% COS-OGA for M. fructigena and M. laxa. Inhibition for B. cinerea, M. fructicola, A. alternata, and A. brassicicola at 0.25% COS-OGA was 86.75%, 76.31%, 69.73%, and 60.45%, respectively. M. laxa and M. fructigena were completely inhibited by CH concentrations of 1–0.25% and M. fructicola by concentrations of 1–0.5%. At CH 0.25%, inhibition for M. fructicola, A. brassicicola, A. alternata, and B. cinerea was 93.99%, 80.99%, 69.73%, and 57.23%, respectively. CH showed effective antibacterial activity against foodborne Escherichia coli. COS-OGA had higher antioxidant activity than CH when assessed by DPPH and hydroxyl radical scavenging assays. Our findings offer insights into the antimicrobial efficacy and mechanisms of action of these novel compounds, which have the potential to serve as alternatives to synthetic pesticides. In vivo investigations are required to validate the prospective application of these treatments for pre- and postharvest disease management. [ABSTRACT FROM AUTHOR]

In 2022, a test performance study (TPS) assessing the influence of different master mixes on the performance of the tetraplex real-time PCR (TqPCR) assay was organized. TqPCR allows for the specific detection and identification of Xylella fastidiosa (Xf) subspecies in a single reaction. Eighteen official laboratories of the Italian National Plant Protection Organization received a panel of 12 blind samples, controls, primers, probes, and different master mixes to participate in the TPS. Furthermore, the Research Centre for Plant Protection and Certification of the Council for Agricultural Research and Economics performed an intra-laboratory study (ITS) on spiked plant matrices to evaluate the analytical sensitivity of TqPCR employing the selected master mixes with the best performance. Naturally infected samples were analyzed for subspecies identification via TqPCR compared with the official multilocus-sequence-typing (MLST) method. The best results in this comparative study were obtained using Fast Universal PCR Master Mix (Applied Biosystems) and Brilliant multiplex QPCR Master Mix (Agilent), and they confirmed that the TqPCR test is reliable, offering the advantage of identifying this subspecies at the same time, thus saving time and resources. The TqPCR assay is suggested among the tests to be used by laboratories performing the official diagnosis of Xf to support the activities of official monitoring. [ABSTRACT FROM AUTHOR]

Gray mold and Rhizopus rot, which is caused by Botrytis cinerea and Rhizopus stolonifer, respectively, are the most destructive forms of postharvest decay of the strawberry fruit. In this work, we tested the effectiveness of the control on the postharvest decay of the strawberry fruit (Fragaria × ananassa Duch cv. 'Monterey') following postharvest applications of six commercial natural compounds: chitosan-based coating compound (1% of 'ChitP', 'ChitS', 'ChitK', 'ChitO'), commercial essential oil (EOs) products based on grapefruit seed extract (0.5% of 'GraFr'), sweet orange (0.5% of 'SwOr'), a product that included eugenol, geraniol, and thymol EO, (0.4% of 'EuGeTh'), an organic compound as humic acid (0.5% w/v of 'HuAc'), and, lastly, methyl jasmonate plant growth regulator (1% v/v 'MeJA'). Strawberries were dipped in solution for 30 s and incubated at room temperature (20 ± 0.5 °C) or at cold storage conditions (4 ± 0.5 °C) following 4 days of shelf life at 20 °C. The treatments with 'ChitP', 'ChitS', and 'ChitO' provided ~30%–40% reduction of gray mold in cold storage conditions, while the 'MeJA', 'SwOr', and 'GraFr' with high activities of volatile substances were more effective at controlling gray mold at room temperature. 'HuAc', 'ChitK', and 'ChitO' were more effective at controlling Rhizopus rot in both cold storage (~50%) and room temperature conditions. [ABSTRACT FROM AUTHOR]

Brassicaceae products have been extensively studied for their biofumigant activity; despite this, few investigate their effect on soil proprieties. This paper aims to describe the effect on soil fertility by adding the seed meal of Brassica carinata at three different doses corresponding to field dose (3 tons/ha), 10 and 100 fold this dose in organic soil. The organic carbon balance was evaluated by analysing the oxidisable, humified and mineralised carbon fractions. Microbial activity was measured by enzymes linked to the carbon, phosphorous and sulphur cycles—β-glucosidase, phosphatase and arylsulphatase, respectively. The amount corresponding to 30 t/ha was the best solution for the mineralised carbon and humic carbon ratio. In contrast, there was a substantial increase in the organic substance's mineralisation level at the maximum dose, not offset by a relative rise in humification. No repression was observed in the metabolic activity of the microorganisms, their abundance or the main enzymatic activities and, in the conditions tested, a release of only a volatile isothiocyanate occurred, limiting the biofumigant effect. Therefore, these combined factors allow us to assert that the amendment with this type of material at the intermediate dose could positively affect the phosphorus cycle, the soil structure, and fertility. [ABSTRACT FROM AUTHOR]

Featured Application: This work provides a reference support to further test the hypothesis that Vitis vinifera cultivars with wide xylem vessels may be more susceptible to esca disease and opens the way to alternative cultural practices and disease management strategies. Esca disease is one of the most important grapevine trunk diseases. It seriously reduces the quality and quantity of grapevine production, and results in a shorter vineyard lifespan. Previous studies have suggested that wide xylem vessel diameter favours development on grapevine of Phaeomoniella chlamydospora, one of the fungi involved in esca, thus affecting disease susceptibility. In this study, cultivars mainly originated from European countries, 27 white-berried and 24 red-berried grapevine cultivars, were grown in the same experimental vineyard and were analysed for xylem vessel sizes (as diameter and frequency) for correlation with esca incidence. In this study, the cultivars showed significant differences in the xylem vessel parameters. However, no relationship was detected between vessel size and esca incidence in the field. Overall, white-berried cultivars showed wider vessel diameters than red-berried cultivars. The relationship between xylem vessel size in the red-berried and white-berried cultivars and incidence of esca symptoms is discussed. We suggest that vessel anatomy profiles can provide useful information for further investigations on grapevine genotype structure–esca incidence relationships. [ABSTRACT FROM AUTHOR]

In this work we analyzed the relationship among native arbuscular mycorrhizal fungi (AMF) and vine roots affected by esca, a serious grapevine trunk disease. The AMF symbiosis was analyzed on the roots of neighboring plants (symptomatic and asymptomatic to esca) in 14 sites of three vineyards in Marche region (central–eastern Italy). The AMF colonization intensity, identified by nonvital staining, showed higher value in all esca symptomatic plants (ranging from 24.6% to 61.3%) than neighboring asymptomatic plants (from 17.4% to 57.6%). The same trend of Glomeromycota phylum abundance was detected by analyzing fungal operational taxonomic units (OTUs) linked to the AMF community, obtained by amplicon high throughput analysis of ITS 1 region. Overall, the highest amount of OTUs was detected on roots from symptomatic plants (0.42%), compared to asymptomatic roots (0.29%). Specific primer pairs for native Rhizophagus irregularis and Funneliformis mosseae AMF species, were designed in 28S rRNA and large subunit (LSU) ribosomal RNA, respectively, and droplet digital PCR protocol for absolute quantification was set up. A higher number of DNA copies of both fungal species were detected more frequently in symptomatic than asymptomatic vines. Our study suggests a relationship between esca and native AMF in grapevine. These results underline the importance of native rhizosphere microbial communities for a better knowledge of grapevine esca disease. [ABSTRACT FROM AUTHOR]