Phytoremediation of Pollutants: Applicability and Future Perspective.

Environmental pollution is a global issue since it is spreading worldwide, affecting entire ecosystems [...].

Use of Biostimulants as a New Approach for the Improvement of Phytoremediation Performance-A Review.

Environmental pollution is one of the most pressing global issues, and it requires priority attention. Environmental remediation techniques have been developed over the years and can be applied to polluted sites, but they can have limited effectiveness and high energy consumption and costs. Bioremediation techniques, on the other hand, represent a promising alternative. Among them, phytoremediation is attracting particular attention, a green methodology that relies on the use of plant species to remediate contaminated sites or prevent the dispersion of xenobiotics into the environment. In this review, after a brief introduction focused on pollution and phytoremediation, the use of plant biostimulants (PBs) in the improvement of the remediation effectiveness is proposed. PBs are substances widely used in agriculture to raise crop production and resistance to various types of stress. Recent studies have also documented their ability to counteract the deleterious effects of pollutants on plants, thus increasing the phytoremediation efficiency of some species. The works published to date, reviewed and discussed in the present work, reveal promising prospects in the remediation of polluted environments, especially for heavy metals, when PBs derived from humic substances, protein and amino acid hydrolysate, inorganic salts, microbes, seaweed, plant extracts, and fungi are employed.

Light and Temperature Shape the Phenylpropanoid Profile of Azolla filiculoides Fronds.

Azolla is a genus of floating freshwater ferns. By their high growth and N2 fixation rates, Azolla species have been exploited for centuries by populations of South-east Asia as biofertilizers in rice paddies. The use of Azolla species as a sustainable plant material for diverse applications, such as feeding, biofuel production, and bioremediation, has encountered a growing interest over the last few years. However, high levels of feed deterrent flavonoids in their fronds have discouraged the use of these ferns as a sustainable protein source for animal consumption. Additionally, information on how and to what extent environmental determinants affect the accumulation of secondary metabolites in these organisms remains poorly understood. Moving from these considerations, here, we investigated by an untargeted metabolomics approach the profiles of phenylpropanoid compounds in the fronds of Azolla filiculoides sampled under control and pigment-inducing stress conditions. In parallel, we assayed the expression of essential structural genes of the phenylpropanoid pathway by quantitative RT-PCR. This study provides novel information concerning A. filiculoides phenylpropanoid compounds and their temporal profiling in response to environmental stimuli. In particular, we show that besides the already known 3-deoxyanthocyanidins, anthocyanidins, and proanthocyanidins, this fern can accumulate additional secondary metabolites of outstanding importance, such as chemoattractants, defense compounds, and reactive oxygen species (ROS) scavengers, and crucial as dietary components for humans, such as dihydrochalcones, stilbenes, isoflavones, and phlobaphenes. The findings of this study open an opportunity for future research studies to unveil the interplay between genetic and environmental determinants underlying the elicitation of the secondary metabolites in ferns and exploit these organisms as sustainable sources of beneficial metabolites for human health.

An ancient RAB5 governs the formation of additional vacuoles and cell shape in petunia petals.

Homologous ("canonical") RAB5 proteins regulate endosomal trafficking to lysosomes in animals and to the central vacuole in plants. Epidermal petal cells contain small vacuoles (vacuolinos) that serve as intermediate stations for proteins on their way to the central vacuole. Here, we show that transcription factors required for vacuolino formation in petunia induce expression of RAB5a. RAB5a defines a previously unrecognized clade of canonical RAB5s that is evolutionarily and functionally distinct from ARA7-type RAB5s, which act in trafficking to the vacuole. Loss of RAB5a reduces cell height and abolishes vacuolino formation, which cannot be rescued by the ARA7 homologs, whereas constitutive RAB5a (over)expression alters the conical cell shape and promotes homotypic vacuolino fusion, resulting in oversized vacuolinos. These findings provide a rare example of how gene duplication and neofunctionalization increased the complexity of membrane trafficking during evolution and suggest a mechanism by which cells may form multiple vacuoles with distinct content and function.

Safe use of Peripherally Inserted Central Catheters for chemotherapy of solid malignancies in adult patients: A 1-year monocentric, prospectively-assessed, unselected cohort of 482 patients.

INTRODUCTION: Aim of this study was to analyze the overall complication and failure rates of Peripherally Inserted Central Catheters (PICCs), in a 1-year consecutive unselected cohort of 482 adult patients, affected by non-hematological malignancies undergoing chemotherapy. METHODS: Adult outpatients (aged 18-75 years), with an Eastern Cooperative Oncology Group (ECOG) performance status of 0-2, bearing solid tumors and candidates for intravenous chemotherapy were eligible for the study. Exclusion criteria were active infections, coagulopathy (defined as platelet count <50,000/µL and/or prothrombin time more than 18 s), life expectancy <6 months, or inability to give written informed consent. Devices were all implanted in an outpatients' hospital facility, following predefined evidence-based institutional guidelines and protocols by a PICC-dedicated team at the European Institute of Oncology in Milan, Italy, during the 12-month period from January 1 to December 31, 2019. RESULTS: Five-hundred PICCs were implanted in a cohort of 482 patients during the time interval of this study. Thirty devices were overall removed (6.2%), 23 as a consequence of a complication occurred, and seven inadvertently. The inserted PICCs accounted for a total of 49,718 catheter days in situ, median duration was 85.5 days [interquartile range (IQR): 56-146]. Overall there were 42 (8.7%) complications, corresponding to 0.84 catheter-adverse events (CAE)/1000 PICC-days (95% CI: 0.61-1.14). There were N = 13 (2.7%) thromboses, N = 11 (2.3%) irreversible occlusions, N = 7 (1.5%) accidental removals, N = 5 (1.0%) infections [two Catheter Related Blood Stream Infection (CRBSI) and three exit site/local infection], N = 3 (0.6%) ruptures and N = 3 (0.6%) primary or secondary malpositions. CONCLUSION: This large prospective study supports the increasing use of PICCs in adult oncology outpatients treated in specialized centers with chemotherapy for non-hematological malignancies. In this clinical setting, PICC failure occurred in 6% only of the inserted devices.

The Influence of Light on Olive (Olea europaea L.) Fruit Development Is Cultivar Dependent.

In olive, the response to environmental conditions, such as light availability, is under genetic control and requires a combination of biochemical and physiological events. We investigated the effect of irradiance in fruit development in two Italian cultivars, Leccino and Frantoio. Morphological and cyto-histological analyses, as well as water and oil content determination, were carried out in fruits exposed to a different light regime (named as light and shade fruits). Results demonstrated that the influence of light availability on fruit development depends on the cultivar. In Leccino, the fresh and the dry weight, the percentage of dry matter, the kernel and fruit diameter, the mesocarp thickness and the mesocarp cell size were higher in the light exposed fruits than in the ones grown in the shade. In Frantoio, differences between light and shade fruits were observed only at 140 DAF (Days After Flowering) and only in the kernel and fruit diameter and in the dry and fresh weight, which were higher in the light exposed fruits. Leccino, therefore, showed a greater sensitivity to the light availability. This may be related to the observed delay in the endocarp lignification as compared to the Frantoio cultivar. In each cultivar, moreover, shade and light fruits did not show differences in the timing of cell differentiation. Finally, the investigation of oil storage carried out in cyto-histological studies demonstrated that differences in oil content between fruit subjected to different light regimes correlated with the number of oil containing cells, rather than the oil content per cell. A different behaviour was observed in the two cultivars: in Leccino, the mesocarp cell size was almost twice of Frantoio, while oil drops were only 30% larger; therefore, the percentage of cell volume occupied by the oil drops was lower in Leccino than in Frantoio. The chemical analysis confirmed this observation.

Metabolite Storage in Theobroma cacao L. Seed: Cyto-Histological and Phytochemical Analyses.

Cocoa (Theobroma cacao L.), an economically important tropical-fruit crop as source of chocolate, has recently gained a considerable attention; its seeds contain a large amount of different bioactive compounds that have attracted interest because may be beneficial to humans by improving cardiovascular health, by cancer chemo-preventive effects and also through neuroprotective activities. The morphological and anatomical characteristics of cocoa seeds are closely related to the aroma and to the nutritional properties. This study aimed to provide more information about the storage of some metabolites in the various components of cocoa seed by microscopical and phytochemical analyses. Polyphenols, sterols, tocopherols and fatty acids were detected in different portions of the seeds (teguments, cotyledons, embryo axis and pulp). Quali and quantitative differences were observed and a characteristic polyphenol pattern was detected in the different portions of the seed; cytological analysis demonstrated the presence of these compounds in big vacuolated polyphenolic cells. Among the analyzed fatty acids, the stearic and oleic acids were the most abundant in all the seed components (teguments, cotyledons and embryo axis). Fatty acids, usually found in the form of esters, thioesters and amides, represent one of the storage substances of cocoa seed probably localized in lipid globules, which in our observations occupied almost the entire volume of small isodiametric cells of cotyledon mesophyll. In the cocoa seeds we observed also a different distribution of sterols: ß-sitosterol and Δ5-avenasterol were the most abundant, above all in the embryo axis; stigmasterol and campesterol were less present in embryo axis and more abundant in teguments; campestanol level was again higher in teguments but lower in cotyledons. The specific localization of different kind of sterols was probably related to a peculiar function. Our experiments demonstrated that all seed components contribute to the metabolites storage, but with interesting differences in the localization and amount of each metabolite.

Applying predictive models to decipher rhizobacterial modifications in common reed die-back affected populations.

The microbiota inhabiting the soil, as well as the rhizosphere, represents a key determinant of several plant functions. Like for humans, dysbiosis of the plant-associated microbiota may be a co-causal agent in disease with still obscure eziology. In the last decades, the common reed Phragmites australis has been deeply studied for its disappearance from natural stands, but no clear causative agents have been identified and no laboratory models of such "reed die-back syndrome" (RDBS) have been developed. In this study, we try to shed light on the RDBS, by comparing the rhizosphere microbiota of five Italian P. australis populations with different degrees of decline. Results obtained showed a biogeographical meaningful pattern of rhizosphere microbiota, coupled with an impact of RDBS. Obtained data allowed to construct a two-steps predictive model which enabled the prediction of the plant health status from the microbiota taxonomic composition, independently from their geographic location. In conclusion, this study represents one of the first overviews that statistically links RDBS to alteration of rhizosphere microbiota and suggests a model for the analysis of plant-bacteria relationships in nature.

AFLP Approach Reveals Variability in Phragmites australis: Implications for Its Die-Back and Evidence for Genotoxic Effects.

Phragmites australis is a subcosmopolitan species typical of wetlands being studied in Europe for its disappearance from natural stands, a phenomenon called reed die-back syndrome (RDBS). Although it is conjectured that low genetic variability contributes to RDBS, this aspect remains neglected to this day. Using a molecular fingerprinting approach and a sequence analysis of the trnT-trnL/rbcL-psaI regions of cpDNA, this study aimed to compare the genetic structure of stable vs. RDBS-affected P. australis stands from five wetlands of central Italy. Beforehand, in order to characterize the health condition of reed populations, the occurrence of the main macromorphological descriptors for RDBS was considered on 40 reed stands. Soil samples were also collected to examine the total content of heavy metals. The current study analyzed cpDNA in 19 samples and AFLP profiles in 381 samples to investigate the genetic structure of Phragmites populations. Based on the multinomial-Dirichlet model, an analysis of candidate loci under selective pressure was also performed. The relationships among AFLP data, RDBS descriptors and chemicals were evaluated with the use of Linear Mixed Models. The analysis of the cpDNA shows the occurrence of the haplotypes M (the most widespread), and K here recorded for the first time in Italy. Three new haplotypes were also described. The DNA fingerprinting analysis has produced a total of 322 loci (98% polymorphic) and shows the medium-to-high amount of genetic diversity. The significant genetic differentiation among wetlands (Fst = 0.337) suggests either low gene flow or small effective population size. Moreover, the low amount of outlier loci (only 5; l.5% of the total), seems to indicate the scarce occurrence of selective pressure upon the reed's genome. Genetic diversity increased in relationship to the decrease in diameter and of flowering buds of the reed, two of the trends associated with the die-back. The current study rejects the hypothesis that genetic diversity massively contributed to RDBS. Moreover, significant relationships between genetic diversity and the total concentration of some heavy metals (Cr, Cu, and Zn) were highlighted, indicating possible genotoxic effects on P. australis. The current study represents a fact-finding background useful for the conservation of common reed.

Oomycete Communities Associated with Reed Die-Back Syndrome.

Phragmites australis (Cav.) Trin. ex Steud. die-back is a widely-studied phenomenon that was first discovered in northern Europe and that, until recently, was almost unknown in the Mediterranean basin. It has been described as a complex syndrome affecting reed populations leading to their retreat and decline, with significant impacts on valuable ecosystem services. Among the factors that cause the decline, soil-living microorganisms can be crucial. The aims of this study were to analyze the diversity of oomycetes communities associated with reed stands, and to understand whether they could play a key role in the decline. Variations in the structure of oomycetes communities were studied by metabarcoding of the internal transcribed spacer (ITS) 1 region of ribosomal DNA, from the sediments of five Italian freshwater ecosystems. They were chosen to cover a large variability in terms of surface area, water depth, microclimate, and presence of documented reed retreat. From 96 samples collected from reed roots, rhizosphere, and bulk soil, we assembled 207661 ITS1 reads into 523 OTUs. We demonstrated that oomycete communities were structured by several factors, among which the most important was die-back occurrence. Our study also indicates that Pythiogeton spp. could be potentially involved in the development of die-back. The role of heavy metals in the soil was also explored, and cadmium concentration was shown to affect oomycetes distribution. This study represents a significant step forward for the characterization of microbial communities associated with reed die-back syndrome and helps to gain knowledge of the complexity of these important wet ecosystems.