Pomegranate transplant stress can be ameliorated by rhizophagus intraradices under nursery management

Arbuscular mycorrhizal fungi (AMF) establish an obligate mutualistic symbiosis with many plant species, increasing the uptake of phosphorous and other low-mobile nutrients by roots. In addition, AMF improve biotic and abiotic stress tolerance of host plants. Under these conditions, reactive oxygen species (ROS) increase occasional damage to proteins, lipids and DNA. Antioxidative enzymes in plants can play an important role in detoxifying ROS, thereby alleviating oxidative stress. In nursery practices, plants are subjected at least to two transplant conditions before being transplanted outside. It is important to achieve an optimal plant size to withstand environmental or other stresses when plants are transplanted into the field. The transplantation process can be considered a stress because plants have to adapt to new abiotic and biotic (rhizospheric) conditions. The aim of this study was to evaluate the effect of two Rhizophagus intraradices (N.C. Schenck & G.S. Sm.) C. Walker & A. Schüßler strains, GA5 and GC2, single and co-inoculated under two-transplant soil conditions, sterile and non-sterile, using cuttings of pomegranate (Punica granatum L.) as a model plant. These results showed that the GA5 single strain-inoculated plants improved growth and antioxidative enzyme responses to two transplant stress conditions. In conclusion, early mycorrhizal inoculation generates healthy plants that are more protected against environmental conditions, thereby improving plant transplant stress tolerance.The authors thank Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Agencia Nacional de Promoción Científica y Tecnológica (ANCyPT) and Universidad de Buenos Aires (UBA) for financial support.Peer Reviewe

Short-term associations between fine and coarse particulate matter and hospitalizations in Southern Europe: Results from the MED-PARTICLES project

Background: Evidence on the short-term effects of fine and coarse particles on morbidity in Europe is scarce and inconsistent. Objectives: We aimed to estimate the association between daily concentrations of fine and coarse particles with hospitalizations for cardiovascular and respiratory conditions in eight Southern European cities, within the MED-PARTICLES project. Methods: City-specific Poisson models were fitted to estimate associations of daily concentrations of particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5), ≤ 10 (PM10), and their difference (PM2.5-10) with daily counts of emergency hospitalizations for cardiovascular and respiratory diseases. We derived pooled estimates from random-effects meta-analysis and evaluated the robustness of results to co-pollutant exposure adjustment and model specification. Pooled concentration-response curves were estimated using a meta-smoothing approach. Results: We found significant associations between all PM fractions and cardiovascular admissions. Increases of 10 μg/m3 in PM2.5, 6.3 μg/m3 in PM2.5-10, and 14.4 μg/m3 in PM10 (lag 0-1 days) were associated with increases in cardiovascular admissions of 0.51% (95% CI: 0.12, 0.90%), 0.46% (95% CI: 0.10, 0.82%), and 0.53% (95% CI: 0.06, 1.00%), respectively. Stronger associations were estimated for respiratory hospitalizations, ranging from 1.15% (95% CI: 0.21, 2.11%) for PM10 to 1.36% (95% CI: 0.23, 2.49) for PM2.5 (lag 0-5 days). Conclusions: PM2.5 and PM2.5-10 were positively associated with cardiovascular and respiratory admissions in eight Mediterranean cities. Information on the short-term effects of different PM fractions on morbidity in Southern Europe will be useful to inform European policies on air quality standards

Molecular and functional characterization of beneficial bacteria associated with AMF spores

In the years to come, a major challenge for agriculture will be the implementation of sustainable intensification of agricultural practice, to ensure sufficient food production for the growing global population and to reduce chemical and energy inputs. This aim may be pursued by promoting the efficient use of beneficial soil microorganisms that play fundamental roles in plant growth and health. Among them, arbuscular mycorrhizal fungi (AMF), and their associated microbiota, can be considered biofertilizers, bioenhancers, and biocontrol agents, showing diverse plant growth-promoting (PGP) properties. Here we focus on approaches for the study of the identity and function of bacteria associated with AMF spores, referred to as spore-associated bacteria (SAB). Culture-independent methods are essential for the identification of their diversity; however, only culture-dependent approaches allow the determination of SAB functional roles, and the selection of the best performing strains, to be tested in laboratory experiments, as well as in the field. The discovery of SAB functional activities, e.g., phosphate solubilization and nitrogen fixation, as well as production of phytohormones, siderophores, and antibiotics, is opening new avenues for their targeted management in agriculture. In this chapter the approaches, techniques, and results relevant to culture independent and culture-dependent studies on beneficial SAB will be reviewed. Significant case studies dealing with SAB utilization as inoculants in experimental trials will be discussed, with the aim of prospecting their utilization, individually or in specially designed multifunctional consortia, in sustainable and innovative food production systems

Associations between fine and coarse particles and mortality in Mediterranean cities: Results from the MED-PARTICLES project

Background: Few studies have investigated the independent health effects of different size fractions of particulate matter (PM) in multiple locations, especially in Europe. Objectives: We estimated the short-term effects of PM with aerodynamic diameter ≤ ; 10; μm (PM10), ≤ 2.5; μm (PM2.5), and between 2.5 and 10; μm (PM2.5-10) on all-cause, cardiovascular, and respiratory mortality in 10 European Mediterranean metropolitan areas within the MED-PARTICLES project. Methods: We analyzed data from each city using Poisson regression models, and combined city-specific estimates to derive overall effect estimates. We evaluated the sensitivity of our estimates to co-pollutant exposures and city-specific model choice, and investigated effect modification by age, sex, and season. We applied distributed lag and threshold models to investigate temporal patterns of associations. Results: A 10-μg/m3 increase in PM2.5 was associated with a 0.55% (95% CI: 0.27, 0.84%) increase in all-cause mortality (0-1 day cumulative lag), and a 1.91% increase (95% CI: 0.71, 3.12%) in respiratory mortality (0-5 day lag). In general, associations were stronger for cardiovascular and respiratory mortality than all-cause mortality, during warm versus cold months, and among those ≥ 75 versus < 75 years of age. Associations with PM2.5-10 were positive but not statistically significant in most analyses, whereas associations with PM10 seemed to be driven by PM2.5. Conclusions: We found evidence of adverse effects of PM2.5 on mortality outcomes in the European Mediterranean region. Associations with PM2.5-10 were positive but smaller in magnitude. Associations were stronger for respiratory mortality when cumulative exposures were lagged over 0-5 days, and were modified by season and age

Desert dust outbreaks in southern Europe: contribution to daily PM10 concentrations and short-term associations with mortality and hospital admissions

BACKGROUND: Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. OBJECTIVES: We aimed to estimate the short-term effects of particulate matter ≤ 10 μm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. METHODS: We identified desert dust advection days in multiple Mediterranean areas for 2001-2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. RESULTS: On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 μg/m3). Most episodes occurred in spring-summer, with increasing gradient of both frequency and intensity north-south and west-east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 μg/m3 in non-desert and desert PM10 (lag 0-1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. CONCLUSIONS: PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections