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

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

How will a drier climate change carbon sequestration in soils of the deciduous forests of Central Europe?

Global warming is accompanied by increasing water stress across much of our planet. We studied soil biological processes and changes in soil organic carbon (SOC) storage in 30 Hungarian oak forest sites in the Carpathian Basin along a climatic gradient (mean annual temperature (MAT) 9.6\u201312.1 C, mean annual precipitation (MAP) 545\u2013725 mm) but on similar gently sloped hillsides where the parent materials are loess and weathered dust inputs dating from the end of the ice age. The purpose of this research was to understand how a drying climate, predicted for this region, might regulate long-term SOC sequestration. To examine the effects of decreasing water availability, we compared soil parameters and processes in three categories of forest that represented the moisture extremes along our gradient and that were defined using a broken-stick regression model. Soil biological activity was significantly lower in the driest (\u2018\u2018dry\u2019\u2019) forests, which had more than double the SOC concentration in the upper 30 cm layer (3.28 g C/100 g soil \ub1 0.11 SE) compared to soils of the wettest (\u2018\u2018humid\u2019\u2019) forests (1.32 g C/100 g soil \ub1 0.09 SE), despite the fact that annual surface litter production in humid forests was * 37% higher than in dry forests. A two-pool SOM model constrained to fit radiocarbon data indicates that turnover times for fast and slow pools are about half as long in the humid soil compared to the dry soil, and humid soils transfer C twice as efficiently from fast to slow pools. Enzyme activity and fungal biomass data also imply shorter turnover times associated with faster degradation processes in the soils of humid forests. Thermogravimetry studies suggest that more chemically recalcitrant compounds are accumulating in the soils of dry forests. Taken together, our results suggest that the predicted climate drying in this region might increase SOC storage in Central European mesic deciduous forests even as litter production decreases

Structures and orientation-dependent interaction forces of titania nanowires using molecular dynamics simulations

Engineering nano wires to develop new products and processes is highly topical due to their ability to provide highly enhanced physical, chemical, mechanical, thermal and electrical properties. In this work, using molecular dynamics simulations, we report fundamental information, about the structural and thermodynamic properties of individual anatase titania (TiO2) nanowires with cross-sectional diameters between 2 and 6 nm, and aspect ratio (Length: Diameter) of 6:1 at temperatures ranging from 300 to 3000 K. Estimates of the melting-transition temperature of the nanowires are between 2000 and 2500 K. The melting transition temperature predicted from the radial distribution functions (RDFs) shows strong agreement with those predicted from the total energy profiles. Overall, the transition temperature is in reasonable agreement with melting points predicted from experiments and simulations reported in the literature for spherical nanoparticles of similar sizes. Hence, the melting-transition temperature of TiO2 nanowires modelled here can be considered as shape independent. Furthermore, for the first time based on MD simulations, interaction forces between two nanowires are reported at ambient temperature (300 K) for different orientations: parallel, perpendicular, and end-to-end. It is observed that end-to-end orientations manifested the strongest attraction forces, while the parallel and perpendicular orientations, displayed weaker attractions. The results reported here could form a foundation in future multiscale modelling studies of the structured titania nanowire assemblies, depending on the inter-wire interaction forces

How Perennial Grass has Modified Distribution of Organic Carbon in a Peach Orchard in Emilia-Romagna Region (Italy)

In this study, the distribution of the total and humified organic carbon in a peach orchard tilled-irrigated on the row and perennial grassed on the inter-row space after 16 years of cultivation were evaluated. The TOC has shown differences not statistically significant in the 0-20 cm horizon, whereas the difference in the row vs. inter-row 20-40 cm horizon was significant. The highest content of humic substances was found in the 0-20 cm of the inter-row with perennial grass vs. row tilled soil: the absence of tillage increases the accumulation of humified compounds. DRIFT and TG-DTA analysis pointed out only some small structural variation in the humic fraction of the samples taken from the layer at depth 20-40 cm