The use of microbial biostimulants in agriculture is recognized as a sustainable approach to promoting crop productivity and quality due to improved nutrient uptake, enhanced stress tolerance, and improved ability to cope with non-optimal environments. The present paper aimed to comparatively investigate the effect of seven different commercial mycorrhizal-based treatments in terms of yield, phytochemical components, and technological traits of Malvasia di Candia Aromatica grape (Vitis vinifera L.) plants. Metabolomic analysis and photosynthetic performance were first investigated in leaves to point out biochemical differences related to plant growth. Higher photosynthetic efficiency and better PSII functioning were found in biostimulant-treated vines, reflecting an overall decrease in photoinhibition compared to untreated plants. Untargeted metabolomics followed by multivariate statistics highlighted a robust reprogramming of primary (lipids) and secondary (alkaloids and terpenoids) metabolites in treated plants. The analysis of berry yield and chemical components exhibited significant differences depending on the biostimulant product. Generally, berries obtained from treated plants displayed improved contents of polyphenols and sugars, while yield remained unchanged. These results elucidated the significant role of microbial biostimulants in determining the quality of grape berries and eliciting biochemical changes in vines.
This study aimed to assess the effectiveness of plant growth-promoting rhizobacteria (PGPR; Pseudomonas strain So_08) and arbuscular mycorrhizal fungi (AMF; Rhizoglomus irregulare BEG72 and Funneliformis mosseae BEG234) in mitigating the detrimental effects of cadmium (Cd) and zinc (Zn) stress in tomato plants. Plant biomass, root morphology, leaf relative water content, membrane stability, photosynthetic performance, chlorophyll content, and heavy metals (HMs) accumulation were determined. Furthermore, an ionomic profile was conducted to investigate whether microbial inoculants affected the uptake and allocation of macro- and micronutrients. Metabolomics with pathway analysis of both roots and leaves was performed to unravel the mechanisms underlying the differential responses to HMs stress. The findings revealed that the levels of HMs did not significantly affect plant growth parameters; however, they affected membrane stability, photosynthetic performance, nutrient allocation, and chlorophyll content. Cadmium was mainly accumulated in roots, whilst Zn exhibited accumulation in various plant organs. Our findings demonstrate the beneficial effects of PGPR and AMF in mitigating Cd and Zn stress in tomato plants. The microbial inoculations improved physiological parameters and induced differential accumulation of macro- and micronutrients, modulating nutrient uptake balance. These results provide insights into the mechanisms underlying the plant-microbe interactions and highlight the differential modulation of the biosynthetic pathways of secondary metabolites related to oxidative stress response, membrane lipids stability, and phytohormone crosstalk.
Plant growth-promoting rhizobacteria (PGPR) with antagonistic activity toward plant pathogenic fungi are valuable candidates for the development of novel plant protection products based on biocontrol activity. The very first step in the formulation of such products is to screen the potential effectiveness of the selected microorganism(s). In this study, non-pathogenic rhizobacteria were isolated from the rhizosphere of tomato plants and evaluated for their biocontrol activity against three species of mycotoxin-producing Alternaria. The assessment of their biocontrol potential involved investigating both fungal biomass and Alternaria toxin reduction. A ranking system developed allowed for the identification of the 12 best-performing strains among the initial 85 isolates. Several rhizobacteria showed a significant reduction in fungal biomass (up to 76%) and/or mycotoxin production (up to 99.7%). Moreover, the same isolates also demonstrated plant growth-promoting (PGP) traits such as siderophore or IAA production, inorganic phosphate solubilization, and nitrogen fixation, confirming the multifaceted properties of PGPRs. Bacillus species, particularly B. amyloliquefaciens and two strains of B. subtilis, showed the highest efficacy in reducing fungal biomass and were also effective in lowering mycotoxin production. Isolates such as Enterobacter ludwigii, Enterobacter asburiae, Serratia nematodiphila, Pantoea agglomerans, and Kosakonia cowanii showed moderate efficacy. Results suggest that by leveraging the diverse capabilities of different microbial strains, a consortium-based approach would provide a broader spectrum of effectiveness, thereby signaling a more encouraging resolution for sustainable agriculture and addressing the multifaceted nature of crop-related biotic challenges.
Cocoa bean fermentation is carried out in different production areas following various methods. This study aimed to assess how the bacterial and fungal communities were affected by box, ground or jute fermentation methods, using high-throughput sequencing (HTS) of phylogenetic amplicons. Moreover, an evaluation of the preferable fermentation method was carried out based on the microbial dynamics observed. Box fermentation resulted in higher bacterial species diversity, while beans processed on the ground had a wider fungal community. Lactobacillus fermentum and Pichia kudriavzevii were observed in all three fermentation methods studied. Moreover, Acetobacter tropicalis dominated box fermentation and Pseudomonas fluorescens abounded in ground-fermented samples. Hanseniaspora opuntiae was the most important yeast in jute and box, while Saccharomyces cerevisiae prevailed in the box and ground fermentation. PICRUST analysis was performed to identify potential interesting pathways. In conclusion, there were noticeable differences between the three different fermentation methods. Due to its limited microbial diversity and the presence of microorganisms that guarantee good fermentation, the box method was found to be preferable. Moreover, the present study allowed us to thoroughly explore the microbiota of differently treated cocoa beans and to better understand the technological processes useful to obtain a standardized end-product.
While bioplastics are gaining wide interest in replacing conventional plastics, it is necessary to understand whether the treatment of the organic fraction of municipal solid waste (OFMSW) as an end-of-life option is compatible with their biodegradation and their possible role in shaping the microbial communities involved in the processes. In the present work, we assessed the microbiological impact of rigid polylactic acid (PLA) and starch-based bioplastics (SBB) spoons on the thermophilic anaerobic digestion and the aerobic composting of OFMSW under real plant conditions. In order to thoroughly evaluate the effect of PLA and SBB on the bacterial, archaeal, and fungal communities during the process, high-throughput sequencing (HTS) technology was carried out. The results suggest that bioplastics shape the communities' structure, especially in the aerobic phase. Distinctive bacterial and fungal sequences were found for SBB compared to the positive control, which showed a more limited diversity. Mucor racemosus was especially abundant in composts from bioplastics' treatment, whereas Penicillium roqueforti was found only in compost from PLA and Thermomyces lanuginosus in that from SBB. This work shed a light on the microbial communities involved in the OFMSW treatment with and without the presence of bioplastics, using a new approach to evaluate this end-of-life option.
Plant Biostimulants (BSs) are a valid supplement to be considered for the integration of conventional fertilization practices. Research in the BS field keeps providing alternative products of various origin, which can be employed in organic and conventional agriculture. In this study, we investigated the biostimulant activity of the eluate obtained as a by-product from the industrial production of lactic acid bacteria on bare agricultural soil. Eluates utilization is in line with the circular economy principle, creating economical value for an industrial waste product. The research focused on the study of physical, chemical, biochemical, and microbiological changes occurring in agricultural soil treated with the biowaste eluate, applied at three different dosages. The final aim was to demonstrate if, and to what extent, the application of the eluate improved soil quality parameters and enhanced the presence of beneficial soil-borne microbial communities. Results indicate that a single application at the two lower dosages does not have a pronounced effect on the soil chemical parameters tested, and neither on the biochemical proprieties. Only the higher dosage applied reported an improvement in the enzymatic activities of ß-glucosidase and urease and in the chemical composition, showing a higher content of total, nitric and ammonia N, total K, and higher humification rate. On the other hand, microbial communities were strongly influenced at all dosages, showing a decrease in the bacterial biodiversity and an increase in the fungal biodiversity. Bioinformatic analysis revealed that some Operative Taxonomic Units (OTUs) promoted by the eluate application, belong to known plant growth promoting microbes. Some other OTUs, negatively influenced were attributed to known plant pathogens, mainly Fusarium spp. Finally, the ecotoxicological parameters were also determined and allowed to establish that no toxic effect occurred upon eluate applications onto soil.
INTRODUCTION: This study developed and validated three questionnaires addressed to the accrediting bodies of the CME system, the providers and the end-users to investigate facilitating factors, barriers and achieved results. Facilitating factors, barriers and achieved results were then described, and the predictors of the achieved result were identified. METHODS: Multiphase and multi-method study. RESULTS: The developed questionnaires show evidence of validity and reliability. 8098 healthcare professionals, 10 accrediting bodies and 206 providers were enrolled to the study. The facilitating factors show the greater predictive capacity in explaining the variance of the perceptions of achieved results in all three groups. DISCUSSION: The common perspectives of the participants guided the creating of a framework aimed to provide guidance for strengthening facilitating factors regarding the activities of accrediting bodies, providers, and end-users of CME education.
COVID-19 , Education, Medical, Continuing , Attitude of Health Personnel , Education, Medical, Continuing/methods , Humans , Reproducibility of Results , Surveys and Questionnaires
