A Lignin-Rich Extract of Giant Reed (Arundo donax L.) as a Possible Tool to Manage Soilborne Pathogens in Horticulture: A Preliminary Study on a Model Pathosystem

Finding new sustainable tools for crop protection in horticulture has become mandatory. Giant reed (Arundo donax L.) is a tall, perennial, widely diffuse lignocellulosic grass, mainly proposed for bioenergy production due to the fact of its high biomass yield and low agronomic requirements. Some studies have already highlighted antimicrobial and antifungal properties of giant reed-derived compounds. This study aimed at investigating the potential of a lignin-rich giant reed extract for crop protection. The extract, obtained by dry biomass treatment with potassium hydroxide at 120◦C, followed by neutralization, was chemically characterized. A preliminary in vitro screening among several pathogenic strains of fungi and oomycetes showed a high sensitivity by most of the soilborne pathogens to the extract; thus, an experiment was performed with the model pathosystem, Pythium ultimum–zucchini in a growth substrate composed of peat or sand. The adsorption by peat and sand of most of the lignin-derived compounds contained in the extract was also observed. The extract proved to be effective in restoring the number of healthy zucchini plantlets in the substrate infected with P. ultimum compared to the untreated control. This study highlights the potential of the lignin-rich giant reed extract to sustain crop health in horticulture

Assessing the potential of the terrestrial cyanobacterium Anabaena minutissima for controlling Botrytis cinerea on tomato fruits

Cyanobacteria are oxygenic phototrophs that have an essential role in soil N2 fixation, fertility, and water retention. Cyanobacteria are also natural sources of bioactive metabolites beneficial to improve plant vigor and potentially active against fungal plant pathogens. Therefore, we studied the antifungal activity of water extract (WE) and phycobiliproteins (PBPs) from Anabaena minutissima strain BEA 0300B against the fungal plant pathogen Botrytis cinerea on tomato fruits and in vitro. The water extract and PBPs were characterized by using FT-IR and FT-Raman spectroscopies. Both water extract (5 mg/mL) and PBPs (ranged from 0.3 to 4.8 mg/mL) reduced disease incidence and disease severity on tomato fruits and mycelium growth and colony forming units in vitro. For mycelium growth, a linear PBP dose-response was found. Tomato fruits were also characterized by FT-IR and FT-Raman spectroscopies in order to evaluate structural modifications induced by pathogen and PBP treatment. PBPs preserved cutin and pectin structures by pathogen challenge. In conclusion, A. minutissima can be considered a potential tool for future large-scale experiments for plant disease control

New insight on tomato seed priming with Anabaena minutissima phycobiliproteins in relation to Rhizoctonia solani root rot resistance and seedling growth promotion

Cyanobacteria phycobiliproteins (PBPs) are already exploited in the food industries and for biotechnological applications but not in the agricultural field. Different concentrations (0.6 - 4.8 mg/mL) of Anabaena minutissima PBPs were applied to tomato seed to study their priming effect against the soil-borne fungal pathogen Rhizoctonia solani and in promoting plant growth. PBPs increased seedling emergence and vigour, showed activity against root rot disease (67%), and enhanced plant dry weight, length, and height. Generally, no dose effect has been observed except for dry weight (55% at 4.8 mg/mL). Seed treatment primed seeds and seedlings by leading to the activation of defence responses raising phenol (26% in hypocotyls) and flavonoid (26 and 45% in hypocotyls and epicotyls, respectively) contents and chitinase (4-fold at 2.4 and 4.8 mg/mL in hypocotyls) and beta-1,3-D-glucanase (up to about 2-fold at all doses in epicotyls) activities. Micro-Attenuated Total Reflection Fourier Transform Infrared revealed changes in functional groups of primed seeds, hypocotyls and exudates released into the agar because of treatment. Protein extract from PBP-primed seedlings inhibited mycelial growth (67% for epicotyl proteins) and caused morphological alterations in hyphae. This research emphasizes the potential priming role of PBPs applied by seed treatment against soil-borne pathogens

Evaluating Ecklonia maxima water-soluble polysaccharides as a growth promoter of tomato seedlings and resistance inducer to Fusarium wilt

Alternatives to chemicals for plant management are increasingly used to reduce environmental pollution. Seed treatment with natural products may act as a priming effect by stimulating seedling growth and plant defence responses against fungal pathogens. In this framework, algae produce a wide variety of bioactive metabolites, which can be used in agriculture as biofertilizers or biostimulants. The purpose of this study was to investigate the possible role of water-soluble polysaccharides (WSPs) from the brown alga Ecklonia maxima applied on tomato seed in enhancing plant growth and inducing resistance to Fusarium oxysporum via modulation of multiple physiological parameters and metabolic pathways. Here, we first characterized the E. maxima WSPs by FT-IR spectroscopy, and then we tested the WSPs as growth promoters on tomato seedlings, and the physiological and defence responses of plants during pathogen infection. We found that WSP seed treatment without pathogen challenge stimulated seedling height and root growth by 24.5 and 62.9%, respectively. Under pathogen infection, plants exhibited long-lasting resistance against F. oxysporum until 46 days after seed treatment. The metabolic changes associated with resistance to Fusarium wilt in plant roots were related to an increase in phenols, flavonoids and protein contents as well as a higher chitinase and beta-1,3-D-glucanase enzyme activity. Moreover, PR1a, PR3 and other defence gene expressions were significantly increased. Resistance to F. oxysporum as a result of WSP seed treatment was also supported by FT-IR analysis of tomato roots. Infected roots showed a decrease in the relative intensity of the bands due to the syringyl ring and amide I and amide II in proteins. In contrast, WSP treatment alone and in the presence of the pathogen exhibited a spectral profile similar to that of the control. This research emphasizes the potential role of algal polysaccharides applied by seed treatment in promoting seedling growth and priming plant resistance against soil-borne pathogens

Comparison of Cardiac and Non-Cardiac Biomarkers for Risk Stratification in Elderly Patients with Non-Massive Pulmonary Embolism.

Biomarkers unrelated to myocardial necrosis, such as cystatin C, copeptin, and mid-regional pro-adrenomedullin (MR-proADM), showed promise for cardiovascular risk prediction. Knowing whether they are comparable to cardiac biomarkers such as high-sensitive cardiac-troponin T (hs-cTnT) or N-terminal pro-Brain natriuretic peptide (NT-proBNP) in elderly patients with acute non-massive pulmonary embolism (NMPE) remains elusive. This study aims at comparing the prognostic accuracy of cardiac and non-cardiac biomarkers in patients with NMPE aged ≥65 years over time. In the context of the SWITCO65+ cohort, we evaluated 227 elderly patients with an available blood sample taken within one day from diagnosis. The primary study endpoint was defined as PE-related mortality and the secondary endpoint as PE-related complications. The biomarkers' predictive ability at 1, 3, 12 and 24 months was determined using C-statistics and Cox regression. For both study endpoints, C-statistics (95% confidence interval) were stable over time for all biomarkers, with the highest value for hs-cTnT, ranging between 0.84 (0.68-1.00) and 0.80 (0.70-0.90) for the primary endpoint, and between 0.74 (0.63-0.86) and 0.65 (0.57-0.73) for the secondary endpoint. For both study endpoints, cardiac biomarkers were found to be independently associated with risk, NT-proBNP displaying a negative predictive value of 100%. Among non-cardiac biomarkers, only copeptin and MR-proADM were independent predictors of PE-related mortality but they were not independent predictors of PE-related complications, and displayed lower negative predictive values. In elderly NMPE patients, cardiac biomarkers appear to be valuable prognostic to identify very low-risk individuals. ClinicalTrials.gov NCT00973596

Towards surface quantum optics with Bose-Einstein condensates in evanescent waves

We present a surface trap which allows for studying the coherent interaction of ultracold atoms with evanescent waves. The trap combines a magnetic Joffe trap with a repulsive evanescent dipole potential. The position of the magnetic trap can be controlled with high precision which makes it possible to move ultracold atoms to the surface of a glass prism in a controlled way. The optical potential of the evanescent wave compensates for the strong attractive van der Waals forces and generates a potential barrier at only a few hundred nanometers from the surface. The trap is tested with Rb Bose-Einstein condensates (BEC), which are stably positioned at distances from the surfaces below one micrometer

Jania adhaerens Primes Tomato Seed against Soil-Borne Pathogens

Managing soil-borne pathogens is complex due to the restriction of the most effective synthetic fungicides for soil treatment. In this study, we showed that seed priming with Jania adhaerens water-soluble polysaccharides (JA WSPs) was successful in protecting tomato plants from the soil-borne pathogens Rhizoctonia solani, Pythium ultimum, and Fusarium oxysporum under greenhouse conditions. WSPs were extracted from dry thallus by autoclave-assisted method, and the main functional groups were characterized by using FT-IR spectroscopy. WSPs were applied by seed treatment at 0.3, 0.6 and 1.2 mg/mL doses, and each pathogen was inoculated singly in a growing substrate before seeding/transplant. Overall, WSPs increased seedling emergence, reduced disease severity and increased plant development depending on the dose. Transcriptional expression of genes related to phenylpropanoid, chlorogenic acid, SAR and ISR pathways, and chitinase and beta-1,3 glucanase activities were investigated. Among the studied genes, HQT, HCT, and PR1 were significantly upregulated depending on the dose, while all doses increased PAL and PR2 expression as well as beta-1,3 glucanase activity. These results demonstrated that, besides their plant growth promotion activity, JA WSPs may play a protective role in triggering plant defense responses potentially correlated to disease control against soil-borne pathogens

Rare-earth doped glasses and light managing in solar cells

Glasses doped with rare earth elements possess unique photoluminescence properties. They find application in several devices, such as lasers, optical amplifiers, and sensors. More recently, rare-earth doped glass thin films have been the subject of investigation for the development of frequency-converting layers able to increase the efficiency of silicon solar cells. Another approach to the improvement of the performance of a solar cell is based on the capture of a larger flux of light by the detector, which can be obtained by surface texture, plasmonics, or waveguide structures. Here, the recent advances in this area will be briefly reviewed