Antonella Vitti

Background: Wheat (Triticum spp.), the most cultivated species worldwide, is threatened by various stresses. Among these, the biotic stresses caused by phytopathogenic fungi, like Fusarium sporotrichioides, are responsible for food losses and mycotoxins poisoning. The green strategy based on recovery and use of frass deriving from Hermetia illucens reared on the standard Gainesville diet was applied, involving durum wheat (Triticum durum Desf. var Simeto) seed priming with 10% frass extract, alone or combined with T. afroharzianum T22 (T22), in pot/soil experiment. For this purpose, the agronomic traits, reduction of damping-off due to F. sporotrichioides, and activity of the pool of antioxidant enzymes involved were evaluated. In addition, the presence of microorganisms in the frass extract with possible plant growth promoting and/or protection activity, was searched. Results: Seed priming determined enhanced wheat growth performance and, in the meantime, a control of the development of disease symptoms, allowing a reduction of damping-off of almost 40% when frass extract and T22 were used together. This was accompanied by an increased antioxidant activity in seedlings derived from primed seeds, enabling them to face stresses in a proper way. In addition, in order to address which component of frass extract was responsible for these effects, Paenibacillus polymyxa was isolated from frass extract, and tested for its antifungal activity in vitro, resulting effective against F. sporotrichioides and also the phytopathogenic fungi Fusarium oxysporum f.sp. lycopersici and Botrytis cinerea. Conclusions: This finding demonstrated that seed priming with frass extract, together with T. afroharzianum T22, could be used as an effective and environmentally friendly strategy to promote wheat growth and, at the same time, effectively control the development of F. sporotrichioides disease. The insights gathered from this research, confirmed the ability of frass to be used in priming technique, opening the door to promising solutions to harness the potential of sustainable agricultural practices and green technologies circular economy-based.

Frass deriving from Hermetia illucens was explored as a new sustainable tool to induce biostimulation and/or antifungal activity in Solanum lycopersicum L. var Cerasiforme and Triticum durum Desf. var Simeto against the soil‐borne pathogens Fusarium spp. Phytotoxicity and in vitro antagonism assessments (mycelial growth inhibition of about 40%) allowed to define the optimal dilution of 10% of pasteurised‐frass extract (pFE) to employ for seed priming. Germination tests on water agar demonstrated the priming effectiveness for wheat, but not for tomato, as the analysed parameters were not positively affected. The pFE was used also in combination with the known biocontrol agent Trichoderma harzianum T22 (T22), demonstrating that they could work together to obtain a good growth promotion and protective effect in wheat. Indeed, the priming with pFE significantly reduced the disease incidence of almost 60% or 80%, compared to the infected control, if used alone or combined with T22, respectively. The ability of frass extract to control F. sporotrichioides in wheat was attributed to both enzymatic and non‐enzymatic responses, due to observed differences in total phenolic content (TPC) and superoxide dismutase activity (SOD) in seedlings derived from treated seeds, compared to untreated control. Our findings highlight the great potential of H. illucens frass as a sustainable, green, and circular economy‐based tool in agricultural systems.

Dittrichia viscosa (L.) Greuter subsp. viscosa (Asteraceae) is a perennial species naturally distributed in arid and marginal areas whose agroecological cultivation could be a useful innovation to produce quality biomass to extract phenolic-rich phytochemical blends. Here, biomass-yield trends were profiled at different growth stages under direct cropping, and inflorescences, leaves, and stems were submitted to water extraction and hydrodistillation. Then, four extracts were investigated for their biological activities in invitro and in planta assays. Extracts inhibited cress (Lepidium sativum)- and radish (Raphanus sativus)-seed germination and root elongation. All samples showed dose-dependent antifungal activity in the plate experiments, inhibiting up to 65% of the growth of the fungal pathogen Alternaria alternata, a leaf-spot disease agent of baby spinach (Spinacea oleracea). However, only the extracts from dried green parts and fresh inflorescences at the highest concentration significantly reduced (54%) the extent of Alternaria necrosis on baby spinach. UHPLC-HRMS/MS analysis revealed that the main specialized metabolites of the extracts are caffeoyl quinic acids, methoxylated flavonoids, sesquiterpene compounds such as tomentosin, and dicarboxylic acids, which may explain the observed bioactivity. Plant extracts obtained through sustainable methodology can be effective in biological agricultural applications.

The aim of this study was to deepen our knowledge on the heritage and traditional uses of some medicinal plants of the Cilento, Vallo di Diano and Alburni National Park (Salerno province) and to evaluate their productive potential, in order to increase possible uses to recover and enhance the territory. Biometric surveys and biomass evaluation were carried out. Two types of aqueous extract were prepared using air-dried samples of six harvested species and tested for anti-germination activity on Lepidium sativum L. Hydrolates were recovered via steam distillation from aromatic species and the chemical–physical characteristics were determined. Historical evidence of industrial activity was collected in the territory of Sanza on Monte Cervati, where lavender essential oil has been distilled in the past century, and characterization of the essential oil components was carried out. The ethnobotanical uses detected mainly concerned traditional medicine and nutritional, ritual, or religious uses. The experimental results highlight that spontaneous medicinal plants could become potential sources of local economic development, with uses not only in the phytotherapeutic sector, but also in others, such as food and agriculture for weed control. Moreover, the evidence derived from industrial archeology could represent a further driving force for the enhancement of the territory’s resources.

Cucumber mosaic virus (CMV), which has great impact on agronomic production worldwide, is both aphid and seed transmitted. Although the mechanisms of aphid transmission have been widely studied, those underlying the ability of CMV to survive and remain infectious during the passage from one generation to the next through the seeds are still to be clarified. Moreover, the viral determinants of seed transmission rate are poorly understood. Three viral genotypes produced from same RNA 1 and 2 components of CMV-Fny but differing in RNA 3 (the wild type CMV-Fny, a pseudorecombinant CMV-Fny/CMV-S and a chimeric CMV previously obtained by our group, named F, FS and CS, respectively) were propagated in Nicotiana tabacum cv Xanthi plants in order to assess differences in tobacco seed transmission rate and persistence through plant generations in the absence of aphid transmission. Seed-growth tests revealed CMV infection in the embryos, but not in the integuments. Seedlings from seed-growth tests showed the presence of all considered viruses but at different rates: from 4% (F, FS) to 16% (CS). Electron microscopy revealed absence (CS) of viral particles or virions without the typical central hole (F and FS). In agreement, structural characteristics of purified CMV particles, assessed by circular dichroism spectroscopy, showed anomalous spectra of nucleic acids rather than the expected nucleoproteins. These alterations resulted in no seed transmission beyond the first plant generation. Altogether, the results show for the first time that correct virion assembly is needed for seed infection from the mother plant but not to seedling invasion from the seed. We propose that incorrect virion formation, self-assembly and architecture stability might be explained if during the first stages of germination and seedling development some tobacco seed factors target viral regions responsible for protein-RNA interactions.

Changes in root organization and colonization could be relevant for wheat’s (Triticum durum Desf.) response to F. culmorum-induced crown rot disease (FCR). We investigated the biocontrol and biostimulant efficiency of seeds coated with T. harzianum T-22 (T-22) of four tetraploid wheat seedlings (ancient Saragolle Lucana and modern Creso, Simeto, and Ciclope). In an in vitro experiment, T-22 repressed F. culmorum mycelium growth by over 50% due to the probable combination of competition for nutrients, mycoparasitism, and antibiosis. The seed germination rate was not significantly affected by T-22 while the F. culmorum-induced decrease in emergence was attenuated in the presence of T-22. Ultimately, an improvement in growth was observed by comparing treated and control seedlings at 21 days after sowing. Inoculation with T-22 resulted in Saragolle Lucana seedlings being 4.69 cm higher while Ciclope and Simeto had main roots that were 9.96 and 8.13 cm longer than the control, respectively. Treated and infected Simeto seedlings were 3.75 cm higher and had roots that were 14.45 cm longer than the control, with little contemporary dense coiling colonization by T-22, like Saragolle Lucana. Seed coating induced the best performance regarding seedling growth and the ability to control the pathogen in Simeto (disease severity reduction rate (DDR) of 20%). The pathogenicity of F. culmorum was reduced in all four durum wheats, although it was highly susceptible to FCR. Ciclope, studied for the first time, showed a decrease in disease incidence from 100 ± 0.00% to 56.67 ± 9.13% and a 30% DDR. The seed coating influenced the seedlings’ response to FCR due to T-22’s different colonization actions. This study provides new explanations for the diverse responses of ancient and modern tetraploid wheat to F. culmorum mediated by T-22 inoculation via seed coating.

With the idea of summarizing the outcomes of studies focusing on the resistance induced by Trichoderma spp. against Botrytis cinerea in tomato, the present paper shows, for the first time, results of a meta-analysis performed on studies published from 2010 to 2021 concerning the cross-talk occurring in the tomato–Trichoderma-B. cinerea system. Starting from an initial set of 40 papers, the analysis was performed on 15 works and included nine parameters, as a result of a stringent selection mainly based on the availability of more than one article including the same indicator. The resulting work not only emphasizes the beneficial effects of Trichoderma in the control of grey mold in tomato leaves (reduction in disease intensity, severity and incidence and modulation of resistance genes in the host), but carefully drives the readers to reply to two questions: (i) What are the overall effects of Trichoderma on B. cinerea infection in tomato? (ii) Do the main effects of Trichoderma differ based on the tomato species, Trichoderma species, amount, type and duration of treatment? At the same time, this meta-analysis highlights some weak points of the available literature and should be seen as an invitation to improve future works to better the conceptualization and measure.