Catello Pane

Novel strains of Bacillus, isolated from compost and compost-amended soils, as biological control agents against soil-borne phytopathogenic fungi

Abstract A stepwise screening strategy made it possible to identify five new Bacillus spp. strains for biocontrol of Rhizoctonia solani, Sclerotinia minor and Fusarium solani. In vitro and in vivo biocontrol activity and M13-PCR DNA-fingerprinting led to the selection of these valuable biological control agents (BCAs) from a wide collection of over 250 candidates. At the end of this selection, the highest potential antagonists were identified at species level by 16S-rRNA gene sequence analysis, and results assigned them to Bacillus subtilis group as Bacillus amyloliquefaciens- and Bacillus methylotrophicus-related strains. In the current study, spore-forming bacteria provided substantial biocontrol of telluric diseases on cress and other different host plants. The strains named 15S and 09C were effective in disease control on Brassica oleracea/R. solani pathosystem, whereas Sclerotinia drop of lettuce was reduced by treatments with the strains 17S and 08C. Finally, the strains 17S and 12S were equally effective to control potato Fusarium rot. The evident zone of inhibition seen in dual culture plates suggested antibiosis-like antagonisms as the main mechanisms used by these bacterial isolates in interaction with the pathogens. Additionally, the API-ZYM method revealed constitutive activity of certain extracellular enzymes that could be involved in plant fortification. Bacillus strains isolated from compost and compost-amended soils are promising BCAs that have potential for practical application as biofungicides.

Effects of on-farm composted tomato residues on soil biological activity and yields in a tomato cropping system

BackgroundThe use of compost may relieve the factors that limit productivity in intensive agricultural systems, such as soil organic matter depletion and soil sickness. Concomitantly, the practice of on-farm composting allows the recycle of cropping green residues into new productive processes.ResultsWe produced four vegetable composts by using tomato biomass residues in an on-farm composting plant. The tomato-based composts were assessed for their chemical, microbiological properties, and their effects on soils and plants were evaluated after their application within a tomato cropping system. Compost characteristics affected plant development and productivity through increased nutrient uptake and biostimulation functions. Soil biological activities, including basal respiration, fluorescein diacetate hydrolysis, β-glucosidase, dehydrogenase, alkaline phosphatase, arylsulphatase, and Biolog community levels of physiological profiles, were differently affected by the on-farm tomato-based composts.ConclusionsChanges in soil activity and community structure due to compost amendments were related to classes of biomolecules such as polysaccharides and lignin-derived compounds, as revealed by nuclear magnetic resonance (NMR) spectra of compost materials. The nutrient content and fertility potential of composts were positively related to the amount of tomato residues present in the feedstock.

Integration of soil solarization with Brassica carinata seed meals amendment in a greenhouse lettuce production system.

Abstract The use of integrated pest management is a valid alternative to conventional chemical treatments. This study was carried out to evaluate the effects of Brassica carinata seed meals amendment, combined with solarization, on soil activity and lettuce cultivation. B. carinata seed meals pellets are biofumigant plant tissues originated as byproducts of the biodiesel industry. Microbiological data combined with lettuce production results suggest that, after biofumigation, soil microbial communities change toward a new equilibrium that creates better root plant conditions to improve high lettuce yields. Moreover, Brassica seed meals, combined with solarization, preserved soil microflora against detrimental effects of heating, as revealed by enzymatic and functional analysis.

Phenolic Composition and Antioxidant and Antiproliferative Activities of the Extracts of Twelve Common Bean (Phaseolus vulgaris L.) Endemic Ecotypes of Southern Italy before and after Cooking

Beans are important dietary components with versatile health benefits. We analysed the extracts of twelve ecotypes of Phaseolus vulgaris in order to determine their phenolic profiles, antioxidant activity, and the in vitro antiproliferative activity. Ultra-performance liquid chromatography with diode array detector (UPLC-DAD) admitted us to detect and quantify some known polyphenols, such as gallic acid, chlorogenic acid, epicatechin, myricetin, formononetin, caffeic acid, and kaempferol. The antioxidant activity (AA) ranged from 1.568 ± 0.041 to 66.572 ± 3.197 mg necessary to inhibit the activity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical by 50% (EC50). The extracts, except those obtained from the nonpigmented samples, were capable of inhibiting the proliferation of the human epithelial colorectal adenocarcinoma (Caco-2) cells, human breast cancer cells MCF-7, and A549 NSCLC cell line. Cultivars differed in composition and concentration of polyphenols including anthocyanins; cooking affected the antioxidant activity only marginally. Qualitative and quantitative differences in phenolic composition between the groups of beans influenced the biological activities; on the other hand, we did not find significant differences on the biological activities within the same variety, before and after cooking.

Use of Spent Coffee Ground Compost in Peat-Based Growing Media for the Production of Basil and Tomato Potting Plants

ABSTRACT A spent coffee ground compost (SCGC) was evaluated as an alternative component of growing media to partially replace commercial peat (CP) and fertilizers in the production of potted plants. Seven mixtures (CP 100% + solid mineral fertilizers, CP 100% + liquid mineral fertilizers, CP 90% + SCGC 10%, CP 80% + SCGC 20%, CP 70% + SCGC 30%, CP 60% + SCGC 40%, and CP 100% without fertilizers) were compared for the production of basil and tomato potted plants. SCGC used in a proportion up to 40% enhanced the general plant stand by affecting the dry weight and the measured foliar parameters. Tomato and basil recorded good growth rates on SCGC-amended media, showing quality indices similar to those obtained under fertilization, evidencing compost plant nutrition provision. SCGC appears to be suitable for application as a partial peat substitute in the production of potted plants.

Screening of plant-derived antifungal substances useful for the control of seedborne pathogens

The effect of plant essential oils, Solanum chilense and Aster sedifolius raw saponins, plant-derived colourants and Brassica carinata glucosinolate-containing tissues, for the control of seedborne fungi Alternaria dauci, Alternaria radicina, Colletotrichum lindemuthianum and Ascochyta rabiei, was evaluated. In vitro assays indicated that oregano essential oil, bark chestnut-derived colourant and B. carinata meals, showed a large spectrum of activity against all pathogens. S. chilense raw saponins were effective against A. dauci and A. radicina, while those from A. sedifolius also inhibited significantly C. lindemuthianum. Screening showed the antifungal potential of natural compounds.

Short-Time Response of Microbial Communities to Waste Compost Amendment of an Intensive Cultivated Soil in Southern Italy

In an intensely cultivated soil in southern Italy, the effects of municipal waste compost on soil activities (basal respiration, β-glucosidase, and fluorescein diacetate (FDA) hydrolysis), Biolog functional diversity, pH, and electrical conductivity (EC) were estimated in a short period following amendment. Treatment with compost at 30 t ha−1 (dry matter) was compared to mineral fertilization and untreated soil. In these poor soils, organic amendment allowed the rapid recovery of an active and biodiverse soil community. While the addition of compost increased all microbial activities and EC, the pH did not change. Conversely, metabolic activity that was positively correlated to FDA hydrolysis rate initially was enhanced by compost but decreased with time and disappeared at the end of the incubation. Results indicated that waste compost amendments affected microbial activities, both at global and functional levels, favoring a rapid return of biological factors of fertility.

Principles of Compost-based Plant Diseases Control and Innovative New Developments

Compost is considered one of the different available sustainable approaches that may be used to prevent, mitigate or to control plant diseases. This is possible through the exploitation of the compost suppressive properties. This chapter aims to address the several aspects of compost suppressivity in order to derive the key principles of this phenomena. In particular, will be elucidate the concepts of compost suppressivity, the mechanisms governing it and the ecological aspects that lead it. Finally, will be reported how compost can be exploited in plant disease management both directly and as suitable source of plant protectants.

COMBINED USE OF BRASSICA CARINATA SEED MEAL, THYME OIL AND A BACILLUS AMYLOLIQUEFACIENS STRAIN FOR CONTROLLING THREE SOIL-BORNE FUNGAL PLANT DISEASES

The effectiveness of non-chemical control methods is a critical point of the research about the development of alternatives to banned and/or unsustainable fungicides. In order to extend the magnitude and/or the spectrum of the control ability of each component, the combination of different tools has been proposed. In this work, glucosinolate-containing Brassica carinata seed meal, combined with essential oils from different aromatic plants and the antagonistic bacteria Bacillus amyloliquefaciens strain 17S, was assayed for the control of the soil-borne phytopathogens Fusarium oxysporum f. sp. lycopersici, Rhizoctonia solani and Sclerotinia minor. Seed meal and essential oils showed significant dose-dependent antifungal effects towards all three pathogens, being able to completely inhibit growth at the highest concentration tested. Moreover, the combination of meal and thyme oil enhanced in vitro antagonistic activity of the B. amyloliquefaciens strain by 37%, on average. The use of these three components in planta experiments revealed that the three-combined treatments proved, in general, high level of biocontrol ability (around 80%), but not better than the treatments on their own in reducing disease levels on Fusarium oxysporum f. sp. lycopersici/tomato and Sclerotinia minor/lettuce pathosystems, except for Rhizoctonia solani on bean.

EFFICACY OF PHENOLIC-RICH EXTRACTS FROM LEAVES OF PEPPER LANDRACES AGAINST ALTERNARIA LEAF BLIGHT OF TOMATO

Plant-derived antifungals have an interesting potential to be used for the sustainable management of plant diseases. In this work, seven different local genotypes of Capsicum annuum, diffused in agricultural areas of Campania Region (Italy), were explored for their potential in providing phytochemical extracts suitable for antifungal applications. Bioactive hydro-methanolic extracts has been assessed for phenolic composition and antioxidant capacity and, then, assayed both in vitro and in planta for the suppression of Alternaria alternata, the causal agent of early blight of tomato. Ultra high-performance liquid chromatography-diode array detection (UPLC-DAD) analysis showed phenolic profiles of each extract, identifying and quantifying the individual known components, including gallic acid, chlorogenic acid, epicatechin, cumaric acid, rutin, ferulic acid and luteolin. The phenolic-rich extracts of all peppers varieties proved to be active against in vitro mycelial development of A. alternata. Dipping artificially infected tomato leaves using extracts at 10 µg GAE ml -1 of total phenolics, reduced foliar early blight disease severity closely to 50%, on average. The role played by the phenolic complex in the antifungal activity and in disease control efficacy of the extracts, has been discussed.