•The topography plays a crucial role in determining drainage effects on water flows.•Nitrogen fluxes are generally enhanced following drainage installation.•Phosphorus and PPP losses are rather ...reduced on artificially drained fields.•This trend may reverse on flat terrain where drainage may reduce on-site retention.•It needs to be considered for any risk assessment or management decisions.
Agricultural intensification has led to a large increase in drained arable land and pastures worldwide over the last two centuries. The installation of land drains not only affects the water balance of a landscape, but also influences the susceptibility to erosion, nutrient cycling, transport of plant protection products (PPPs) and greenhouse gas emissions. Due to the complex nature of environmental systems, the direction in which the substance flows are affected remains unclear, as does the strength of the effects. In this literature review, the focus is on the most relevant site-specific factors that affect the soil moisture regime, erosion, nitrogen (N) and phosphorus (P) fluxes, and PPP fluxes under undrained and drained conditions. The considered factors are the topography, soil characteristics, drainage types, rainfall characteristics and land management. Case studies from temperate climate zones represent the basis of the discussion, with a focus on continental Europe and the USA.
In most cases, drainage enhances the total annual water flows from arable fields, while the effects on peak flows were variable, with the local topography playing a crucial role. There exists a certain level of consensus in the literature that subsurface drainage methods reduce the risk of erosion, while surface drainage may increase erosion at the edge of drainage channels. Nitrogen fluxes are generally enhanced following drainage. This is especially true for organic soils with large stores of organically bound N and, therefore, a high loss potential. For P losses, the trend goes in the opposite direction, with generally reduced losses seen following drainage installation. Similar findings are expected in relation to PPP losses. However, these trends may reverse on flat terrain, where subsurface drainage may reduce the on-site retention of these compounds. Overall, the literature reveals the patterns by which drainage affects hydrology, nutrient and PPP fluxes, although it is also evident that the combination of site-specific factors is influential. This hence needs to be considered as part of any risk assessment or management decisions.
Melatonin is a pleiotropic molecule with many diverse actions in plants. It is considered primarily an antioxidant with important actions in the control of reactive oxygen and nitrogen species (ROS ...and RNS), among other free radicals, and harmful oxidative molecules present in plant cells. In addition, plant melatonin is involved in multiple physiological actions, such as growth, rooting, seed germination, photosynthesis, and protection against abiotic and/or biotic stressors. The recent identification of the first plant melatonin receptor opened the door to this regulatory molecule being considered a new plant hormone. However, due to the diversity of its actions, melatonin has also been proposed as a plant master regulator. Here, we discuss the most recent data in respect to both perspectives.
Plant melatonin is involved in multiple physiological actions, including growth, rooting, seed germination, photosynthesis, osmoregulation, and protection against abiotic and biotic stressors.
Plant melatonin not only acts as an antioxidant, but also induces substantial changes in gene expression in many physiological processes.
Recently, the first plant melatonin receptor was identified and characterized in Arabidopsis thaliana.
Many data indicate that plant melatonin could be considered a new plant hormone, although its multiple actions also point to it being an important master regulator of redox homeostasis in plants.
Diverse molecular processes regulate the interactions between plants and insect herbivores. Here, we review genes and proteins that are involved in plant-herbivore interactions and discuss how their ...discovery has structured the current standard model of plant-herbivore interactions. Plants perceive damage-associated and, possibly, herbivore-associated molecular patterns via receptors that activate early signaling components such as Ca
, reactive oxygen species, and MAP kinases. Specific defense reprogramming proceeds via signaling networks that include phytohormones, secondary metabolites, and transcription factors. Local and systemic regulation of toxins, defense proteins, physical barriers, and tolerance traits protect plants against herbivores. Herbivores counteract plant defenses through biochemical defense deactivation, effector-mediated suppression of defense signaling, and chemically controlled behavioral changes. The molecular basis of plant-herbivore interactions is now well established for model systems. Expanding molecular approaches to unexplored dimensions of plant-insect interactions should be a future priority.
Molecular syntheses largely rely on time‐ and labour‐intensive prefunctionalization strategies. In contrast, C−H activation represents an increasingly powerful approach that avoids lengthy syntheses ...of prefunctionalized substrates, with great potential for drug discovery, the pharmaceutical industry, material sciences, and crop protection, among others. The enantioselective functionalization of omnipresent C−H bonds has emerged as a transformative tool for the step‐ and atom‐economical generation of chiral molecular complexity. However, this rapidly growing research area remains dominated by noble transition metals, prominently featuring toxic palladium, iridium and rhodium catalysts. Indeed, despite significant achievements, the use of inexpensive and sustainable 3d metals in asymmetric C−H activations is still clearly in its infancy. Herein, we discuss the remarkable recent progress in enantioselective transformations via organometallic C−H activation by 3d base metals up to April 2019.
Abundant and inexpensive: Inexpensive naturally occurring 3d transition metals with low toxicitiy faciliate enantioselective C−H activation thanks to novel ligand design.
Disease suppressive soils typically develop after a disease outbreak due to the subsequent assembly of protective microbiota in the rhizosphere. The role of the plant immune system in the assemblage ...of a protective rhizosphere microbiome is largely unknown. In this study, we demonstrate that Arabidopsis thaliana specifically promotes three bacterial species in the rhizosphere upon foliar defense activation by the downy mildew pathogen Hyaloperonospora arabidopsidis. The promoted bacteria were isolated and found to interact synergistically in biofilm formation in vitro. Although separately these bacteria did not affect the plant significantly, together they induced systemic resistance against downy mildew and promoted growth of the plant. Moreover, we show that the soil-mediated legacy of a primary population of downy mildew infected plants confers enhanced protection against this pathogen in a second population of plants growing in the same soil. Together our results indicate that plants can adjust their root microbiome upon pathogen infection and specifically recruit a group of disease resistance-inducing and growth-promoting beneficial microbes, therewith potentially maximizing the chance of survival of their offspring that will grow in the same soil.
Plant growth promoting rhizobacteria (PGPR) hold promising future for sustainable agriculture. Here, we demonstrate a carotenoid producing halotolerant PGPR Dietzia natronolimnaea STR1 protecting ...wheat plants from salt stress by modulating the transcriptional machinery responsible for salinity tolerance in plants. The expression studies confirmed the involvement of ABA-signalling cascade, as TaABARE and TaOPR1 were upregulated in PGPR inoculated plants leading to induction of TaMYB and TaWRKY expression followed by stimulation of expression of a plethora of stress related genes. Enhanced expression of TaST, a salt stress-induced gene, associated with promoting salinity tolerance was observed in PGPR inoculated plants in comparison to uninoculated control plants. Expression of SOS pathway related genes (SOS1 and SOS4) was modulated in PGPR-applied wheat shoots and root systems. Tissue-specific responses of ion transporters TaNHX1, TaHAK, and TaHKT1, were observed in PGPR-inoculated plants. The enhanced gene expression of various antioxidant enzymes such as APX, MnSOD, CAT, POD, GPX and GR and higher proline content in PGPR-inoculated wheat plants contributed to increased tolerance to salinity stress. Overall, these results indicate that halotolerant PGPR-mediated salinity tolerance is a complex phenomenon that involves modulation of ABA-signalling, SOS pathway, ion transporters and antioxidant machinery.
Drought is one of the environmental stresses that threaten food availability. It results in decreased crop yields and developments and diminishes overall plant health. Chemical solutions for ...alleviating drought stress may be harmful to the environment. Using an alternative, microorganisms help counter the effects of drought stress. Endophytes have a mutualistic relationship with the host as they provide protection and get nutrients. Fungal endophytes assist plants in countering the damaging results of drought stress by producing phytohormones and growth-promoting compounds that promote root and shoot growth and enhance crop productivity. Inoculating maize plants with endophytic fungi like Fusarium oxysporum and Penicillium sp. have a higher chance of surviving drought stress. These organisms can increase root length, allowing moisture to reach deeper into the soil. This review explores endophytic fungi's roles in alleviating drought stress's consequences on plants. More investigations should be carried out on the favourable effects of fungal endophytes in the mitigation of drought stress through pot and field inoculation.
Flavonoids are small molecular secondary metabolites synthesized by plants with various biological activities. Due to their physical and biochemical properties, they are capable of participating in ...plants' interactions with other organisms (microorganisms, animals and other plants) and their reactions to environmental stresses. The majority of their functions result from their strong antioxidative properties. Although an increasing number of studies focus on the application of flavonoids in medicine or the food industry, their relevance for the plants themselves also deserves extensive investigations. This review summarizes the current knowledge on the functions of flavonoids in the physiology of plants and their relations with the environment.
In this review, we examined the European legislative context on water protection concerning pesticide residues monitoring and the relevant National Action Plans and strategies that were undertaken in ...European countries to better identify and manage the problem in water bodies.
Furthermore, we illustrated the development of analytical methodologies and criticalities connected to determine pesticide residues in water matrices, including sampling, sample preparation approaches, instrumental analyses and specific applications emphasising those works published after 2015.
Details about sampling strategies, analytical feasibility, official methods, degradation products and behaviour in the environment for a subset of 160 pesticides are also provided.
•Need to monitor the use of pesticides continuously given the wide variety of molecules present in this category•An overview of official methods is provided for a subset of 160 pesticides•Sensitive technologies for micro-extraction include SBSE, SPME Arrows, Hi-SORBTM•New advances in preparation techniques focused on Ice Concentration Linked with Extractive Stirrer (ICECLES) have potentialities for more polar pesticides•Recent developments in pesticides analytical techniques focus on multiresidual LC-MS/MS based methods.
Apples are among the most consumed fruits world-wide. They represent a source of direct human exposure to bacterial communities, which is less studied. We analyzed the apple microbiome to detect ...differences between tissues and the impact of organic and conventional management by a combined approach of 16S rRNA gene amplicon analysis and qPCR, and visualization using fluorescence
hybridization and confocal laser scanning microscopy (FISH-CLSM). Each apple fruit harbors different tissues (stem, peel, fruit pulp, seeds, and calyx), which were colonized by distinct bacterial communities. Interestingly, fruit pulp and seeds were bacterial hot spots, while the peel was less colonized. In all, approximately 10
16S rRNA bacterial gene copy numbers were determined in each g apple. Abundances were not influenced by the management practice but we found a strong reduction in bacterial diversity and evenness in conventionally managed apples. In addition, despite the similar structure in general dominated by
(80%),
(9%),
(5%), and
(3%), significant shifts of almost 40% of bacterial genera and orders were monitored. Among them, especially bacterial signatures known for health-affecting potential were found to be enhanced in conventionally managed apples. Our results suggest that we consume about 100 million bacterial cells with one apple. Although this amount was the same, the bacterial composition was significantly different in conventionally and organically produced apples.
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