Leonian (PHC) is a filamentous pathogen oomycete that causes root, fruit, foliar and crown rot over a wide host range, including the economically and nutritionally important summer squash (
var.
L.) ...crop. PHC chemical control strategies are difficult to adopt, due to the limited number of registered chemicals that are permitted and the scalar harvest system. For these reasons, other strategies, such as the use of waste-based composts that can act as suppressive agents against several soilborne pathogens, have been studied intensively. It is well known that compost's microbiota plays an important role to confer its suppressive ability. In this study, four different composts were analyzed with both 16S rRNA gene and 18S rRNA gene real-time PCR amplification and with 26S gene amplicon-based sequencing; the total abundance of the bacterial and fungal communities was found to be higher compared to literature, thus confirming that the four composts were a good inoculum source for agricultural applications. The core mycobiota was mainly composed of 31 genera; nevertheless, it was possible to observe a clear predominance of the same few taxa in all the composts. The four composts were then tested, at different concentrations (1-10-20% v/v), to establish their ability to confer suppressiveness to the
(PHC) -
pathosystem in controlled greenhouse pot trials. A total of 12 compost mixtures were considered, and of these, one (
-enriched compost at 10% v/v) was able to statistically reduce the disease incidence caused by PHC (by 50% compared to the untreated control). Hence, the microbiota composition of the most effective compost treatment was investigated and compared with untreated and chemical (metalaxyl) controls. Mycobiota sequencing showed genera differences between the three treatments, with relative abundances of several fungal genera that were significantly different among the samples. Moreover, PCA analyses clustered the compost treatment differently from the chemical and the untreated controls. These findings suggest that suppressive activity of a compost is strictly influenced by its microbiota and the applied dosage, but the ability to induce a shaping in the rhizosphere microbial composition is also required.
Aspergillus fumigatus, the causal agent of human aspergilloses, is known to be non-pathogenic in plants. It is present as saprophyte in different types of organic matter and develops rapidly during ...the high-temperature phase of the composting process. Aspergilloses are treated with demethylation inhibitor (DMI) fungicides and resistant isolates have been recently reported. The present study aims to estimate the abundance, genetic diversity and DMI sensitivity of A. fumigatus during the composting process of orange fruits. Composting of orange fruits resulted in a 100-fold increase in A. fumigatus frequency already after 1 week, demonstrating that the degradation of orange fruits favoured the growth of A. fumigatus in compost. Most of A. fumigatus isolates belonged to mating type 2, including those initially isolated from the orange peel, whereas mating type 1 evolved towards the end of the composting process. None of the A. fumigatus isolates expressed simultaneously both mating types. The 52 investigated isolates exhibited moderate SSR polymorphisms by formation of one major (47 isolates) and one minor cluster (5 isolates). The latter included mating type 1 isolates from the last sampling and the DMI-resistant reference strains. Only few isolates showed cyp51A polymorphisms but were sensitive to DMIs as all the other isolates. None of the A. fumigatus isolates owned any of the mutations associated with DMI resistance. This study documents a high reproduction rate of A. fumigatus during the composting process of orange fruits, requesting specific safety precautions in compost handling. Furthermore, azole residue concentrations in orange-based compost were not sufficient to select A. fumigatus resistant genotypes.
Viticulture is a cropping system in which treatment against fungal diseases (in particular powdery and downy mildews) can be extremely frequent. Accordingly, a reduction in antimicrobial treatments ...and the application of environmentally-friendly compounds are becoming increasingly important for a more sustainable viticulture. In addition to their effect against pathogens, the impact of these products on the quality of the grapes is very important for the oenological industries, but unfortunately at present few data are available. We evaluated the effect of the application of biocontrol products and resistance inducers in the vineyard on the mechanical properties, microbial ecology, technological and phenolic maturity of
Vitis vinifera
“Nebbiolo” grapes at harvest. The yield and vigor of vines were not influenced by the treatments, nor were the production of primary and secondary metabolites. However, the active ingredients influenced the mechanical properties of the skin (hardness and thickness). A significant hardening of the skin was detected when laminarin and chito-oligosaccharides were used, and sulfur induced a thickening of the skin with potential consequences for wine quality. Furthermore, the yeast community present on grape berries was influenced by the treatments. The abundance of
Aureobasidium pullulans
, the dominant species on the grape berry, changed in response to the compounds used. In addition,
Alternaria
sp. was reduced in some treatments with a potentially positive effect on the quality and the safety of the grapes. This study provides an overview of the effect of biocontrol products and resistance inducers on microbial ecology and “Nebbiolo” grape quality, contributing to the establishment of more sustainable and effective defense strategies in viticulture.
Effects of anaerobic soil disinfestation (ASD) on Rhizoctonia solani basal rot of lettuce were assessed considering: two soil types; different C-sources; different temperature regimes; two treatment ...durations; and two lettuce crop cycles, in the presence of a high disease incidence from artificial infestation with the pathogen. C-source, temperature, and incubation period, and their interaction, affected the efficacy of the ASD treatment for the lettuce-R. solani pathosystem, with differences depending on the soil type. Brassica carinata pellets, used as a C-source, reduced incidence of Rhizoctonia basal rot in the first crop cycle by 50 to 69% in a peat soil after 3 weeks of treatment at 21degreesC, and by 52 to 60% after 3 weeks of treatment at 26 or 31degreesC, compared to the inoculated and untreated experimental controls without anaerobic conditions. The best disease reduction was provided by B. carinata pellets applied, under anaerobic conditions, to peat soil (79% efficacy) and a sandy loam soil (100% efficacy) kept at 31degreesC for 6 weeks. Generally, ASD based on B. carinata pellets provided greater disease reduction in the first crop cycle than the second, with the only exception being for results achieved in both soils incubated for 6 weeks at 21, 26 and 31degreesC. Wild rocket used as a C-source provided the greatest disease reduction (78-83%) on plants grown in peat soil at the first crop cycle after 6 weeks of the ASD treatment at 31degreesC, while wild rocket provided disease reduction of 29 and 50% when mixed with the sandy-loam soil under the same conditions for 6 weeks. The efficacy of the ASD treatment with compost was improved in the second crop cycle, compared to the first, resulting in the greatest disease reduction (52 and 66% efficacy) reached in the sandy-loam soil incubated for 3 weeks at 21degreesC, and 63% efficacy in peat soil previously treated for 6 weeks at 26 and 31degreesC. However, slight reductions in lettuce plant development was generally evident in the first crop cycle, which could be due to differences in efficacy of the tested ASD treatments and to phytotoxicity. The greatest yield from sandy loam soil was obtained for the B. carinata pellets and wild rocket at 26 and 31degreesC in the second cultivation cycle. Partial efficacy of ASD does not justify the adoption of this method against R. solani on lettuce under intensive crop systems. However, ASD based on Brassicaceae and compost as carbon source applied in a sandy-loam soil may be valuable for reducing R. solani incidence, at lower temperatures than those required for soil solarisation or biosolarisation. Keywords. Lactuca sativa, pre-plant treatments, soil-borne pathogens, biological soil disinfestation.
Microbial-based products (either as biopesticide or biofertilizers) have a long history of application, though their use is still limited, mainly due to a perceived low and inconsistent efficacy ...under field conditions. However, their efficacy has always been compared to chemical products, which have a completely different mechanism of action and production process, following the chemical paradigm of agricultural production. This paradigm has also been applied to regulatory processes, particularly for biopesticides, making the marketing of microbial-based formulations difficult. Increased knowledge about bioinocula behavior after application to the soil and their impact on soil microbiome should foster better exploitation of microbial-based products in a complex environment such as the soil. Moreover, the multifunctional capacity of microbial strains with regard to plant growth promotion and protection should also be considered in this respect. Therefore, the methods utilized for these studies are key to improving the knowledge and understanding of microbial-based product activity and improving their efficacy, which, from farmers' point of view, is the parameter to assess the usefulness of a treatment. In this review, we are thus addressing aspects related to the production and formulation process, highlighting the methods that can be used to evaluate the functioning and impact of microbial-based products on soil microbiome, as tools supporting their use and marketing.
The date palm (
Phoenix dactylifera
L.) and other palm species have recently been threatened by the red palm weevil (RPW)
Rhynchophorus ferrugineus
Olivier, which is very difficult to be detected at ...early stage. This research tested non invasive approaches to detecting RPW including: a TreeRadarUnit™ (TRU); a densitometer, a penetrometer used for evaluation of the standing trees stability; a thermal camera and a digital camera. The technologies were applied in Italy on 715 palms (173
P. dactylifera
, 453
Phoenix canariensis
Chabaud and 311 of other palm species), and on 86 adult date palms in Saudi Arabia. In Italy, the thermal camera showed a high accuracy (96.29%) compared to close visual observation over the following nine months. The digital camera did almost as well (92.57%). Tree Radar Unit and densitometer also showed good accuracy (83.33 and 88.89% respectively). In the Kingdom of Saudi Arabia, the thermal camera showed a good accuracy (77.73%) when compared to invasive diagnosis (i.e. cutting down and opening up palm trunks). The digital camera showed a lower accuracy of 66.67% due to the fact that the red weevil mainly attacks the base of the stem and therefore there are no visible symptoms on the crown shape that would be picked up in image analysis. TRU gave good results (74.73% compared to invasive diagnosis), with the best accuracy at ground level (80.65%). The densitometer results were similar to the TRU case, with higher accuracy (82.26% compared to invasive diagnosis) and the highest at ground level (87.10%).
Market implementation of integrated biorefinery requires reliable and advanced processing units combined with eco-friendly and economically profitable production chains. Future developments of ...integrated biorefinery systems should include either crop cultivation with selected genotypes that maximize full chain performances either the increasing use of disposable or/and underused biomass. The aim of this paper was to review the main biorefining opportunities related to agro-bioenergy co-products and agroindustrial residues potentially available on the World (as biofuel co/by-products, agricultural residues, agricultural by-products and agro-wastes), paying a special attention to high-value added products associated to some emerging markets. The current status and future perspectives of conversion from agro-bioenergy residual biomass into high-value bio-based products by innovative biorefineries have been considered. After a brief recognition on the nature and origin of the main categories of organic residuals derived from the biofuel chains and agricultural, forestry, food processing and animal activities within definitions given by the European Union, this paper has firstly focused its choice on the high-value added products associated to some chemical basic-platforms (succinic acid, cellulose, glycerin, proteins, peptides, enzymes, etc.). A special attention has also been done to high-value added bio-based products and commodities related to sustainable and renewable farming systems (soil amendment, phytosanitary drug, plant biostimulant and biofertilizer) and bio-based industries in producing innovative biomaterials (bioplastic, lignin and alginate). Finally, this paper has addressed own concern on the perspectives of integrated biorefining from organic residuals drawing particular attention to the European and Italian contexts giving and discussing some new opportunities for big players and stakeholders.
Disrupted nutrient recycling is a significant problem for Europe, while phosphorus and nitrogen are wasted instead of being used for plant nutrition. Mineral phosphate is a critical raw material, ...which may contain environmentally hazardous elements such as cadmium and uranium. Therefore, phosphorus recovery from agricultural and food industrial by-product streams is a critically important key priority. Phosphorus recovery from food grade animal bone by-products have been researched since 2002 and a specific zero emission autothermal carbonization system, called 3R, has been developed in economical industrial scale, providing the animal bone char product (ABC) as output. Different animal bone by-products were tested under different conditions at 400 kg/h throughput capacity in the continuously operated 3R system. Different material core treatment temperatures (between >300 °C and <850 °C) were combined with different residence times under industrial productive processing conditions. It was demonstrated that material core treatment temperature <850 °C with 20 min residence time is necessary to achieve high quality ABC with useful agronomic value. The output ABC product has concentrated >30% phosphorus pentoxide (P2O5), making it a high quality innovative fertilizer.
Abstract
Grapevine may be affected simultaneously by several pathogens whose complex interplay is largely unknown. We studied the effects of infection by two grapevine viruses on powdery mildew and ...downy mildew development and the molecular modifications induced in grapevines by their multiple interactions. Grapevine fanleaf virus (GFLV) and grapevine rupestris stem pitting-associated virus (GRSPaV) were transmitted by in vitro-grafting to
Vitis vinifera
cv Nebbiolo and Chardonnay virus-free plantlets regenerated by somatic embryogenesis. Grapevines were then artificially inoculated in the greenhouse with either
Plasmopara viticola
or
Erysiphe necator
spores. GFLV-infected plants showed a reduction in severity of the diseases caused by powdery and downy mildews in comparison to virus-free plants. GFLV induced the overexpression of stilbene synthase genes, pathogenesis-related proteins, and influenced the genes involved in carbohydrate metabolism in grapevine. These transcriptional changes suggest improved innate plant immunity, which makes the GFLV-infected grapevines less susceptible to other biotic attacks. This, however, cannot be extrapolated to GRSPaV as it was unable to promote protection against the fungal/oomycete pathogens. In these multiple interactions, the grapevine genotype seemed to have a crucial role: in ‘Nebbiolo’, the virus-induced molecular changes were different from those observed in ‘Chardonnay’, suggesting that different metabolic pathways may be involved in protection against fungal/oomycete pathogens. These results indicate that complex interactions do exist between grapevine and its different pathogens and represent the first study on a topic that still is largely unexplored.
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