Unexposed Plants Research Articles

Effects of TiO2 ultraviolet filter and sunscreens on coastal dune plant performance and competitive interactions

Ultraviolet filters (UVFs) added to sunscreens (SS) are emerging contaminants in marine environments due to their adverse effects on organisms and ecosystems. UVFs have also been detected in beach-dune systems, but their influence on resident organisms has not been explored yet. Native plants are fundamental components of coastal dunes, and these ecologically/economically important systems are currently among the most threatened globally. Thus, understanding whether UVFs may act as threats to dune plants is crucial. This field study evaluated and compared the effects of titanium dioxide nanoparticles (nTiO2), one of the inorganic UVFs most commonly added to sunscreens, and those of a commercial sunscreen product containing it (SS-nTiO2) on the performance of adult dune plants of a native (Thinopyrum junceum) and a non-native invasive species (Carpobrotus sp. pl.) and their competitive interactions at environmentally realistic concentrations. The effects of nTiO2, SS-nTiO2 and of a sunscreen product containing just organic UVFs (SS-OF) on early life stages of T. junceum were also examined. Ti bulk content in sand and plants at the study site ranged from 970 to 1069 mg kg−1 and from 2 to 7.9 mg kg−1, respectively. Thinopyrum junceum adult plants periodically exposed during the summer season to seawater contaminated by SS-nTiO2 produced less biomass than un-exposed plants and nTiO2 exposed plants. nTiO2 and SS-nTiO2 reduced the capacity of T. junceum to control the spread of Carpobrotus. Both SS-nTiO2 and SS-OF reduced seedling emergence in T. junceum whereas nTiO2 did not. These results demonstrated that the periodical exposures of native dune plants to sunscreens could reduce their establishment success and growth and favor invasive plant spread potentially resulting in community structure changes. They also emphasize the need to assess the phytotoxicity not only of single UVFs but especially that of complete sunscreen products to design more eco-friendly formulations in the future.

TiO2 nanoparticles alter nutrients acquisition, growth, biomacromolecules, oil composition and modulate antioxidant defense system in Mentha arvensis L.

The current study demonstrates the impact of TiO2 NPs (0–5 µg ml−1) on Mentha arvensis L. (Lamiaceae) cultivated commercially for essential oil. The high concentration of titanium in plant tissues (roots, leaves and stem), presence of Ti peaks in EDS of roots and accumulation of TiO2 NPs along the inner and outer membrane, cytoplasm, intracellular junctions of M. arvensis root cells after TiO2 NPs exposure reveal internalization and upward translocation of TiO2 NPs in M. arvensis. Phytotoxicity of TiO2 NPs manifested in terms of altered nutrients acquisition, reduced biomass, pigments, relative water contents and enhanced oxidative stress markers ( ≥ 2.5 µg ml−1 TiO2 NPs) in roots and leaves. Further, TiO2 NPs incremented the levels of cysteine, non-protein thiols, and proline compared to untreated control. Total phenolic contents also increased (≤1 µg ml−1 TiO2 NPs) in roots and leaves. Modulation of antioxidant enzymes (SOD, catalase, GPX, APX, AO and GST) in roots and leaves was observed to mitigate adverse effects caused by TiO2 NPs induced reactive oxygen species. TiO2 NPs differentially affects cell wall components, lipids and nucleic acids in roots and leaves. The relative peak area (%) of major oil constituents in M. arvensis leaves was significantly altered by TiO2 NPs. A concentration dependent decrement in relative peak area of α-pinene, β- pinene, Sabinene, Limonene, β – Myrcene has been documented in this study compared to unexposed plants. The present study suggests sustainable use of TiO2 NPs in agriculture and other commercial products due to their potential biotoxicity.

Phytoremediation of heavy metals from landfill soil using Polyscias fruticosa

The presence of heavy metals in landfill soil by industrial or anthropogenic activities pose a risk to the environment and it is one of the major concerns. This study was to determine and evaluate the capability of Polyscias fruticosa in the phytoremediation of heavy metals from abandoned landfill soil. P. fruticosa was analysed to evaluate its tolerance and phytoremediation ability on landfill soil in a greenhouse study with a harvesting period of 1-month intervals. Ninety-six (96) cuttings from P. fruticosa were transplanted and had the same treatment in 500 g landfill soil. The roots, stems, and leaves of exposed and unexposed plants were dry-digested and heavy metals were determined using Atomic Absorption Spectrophotometer (AAS). The height and weight of dry biomass of exposed and unexposed plants were determined. The data obtained were subjected to a one-way analysis of variance and the least significant difference (L.S.D.) at probability level p<0.05. The highest accumulation in the roots occurred on Pb, followed by Cr, As, and Cd with concentrations 0.82, 0.68, 0.35, and 0.33 mg/kg, respectively. Heavy metals were not detected from unexposed plant and soil. The three indices, bioconcentration, translocation factors, and extraction coefficient, were found to be more significant (>1) on six months compared to other harvesting periods. The percentage removal was Cd 88%, As 87%, Cr 86%, and Pb 78%. The results indicate that P. fruticosa might be an effective species to reduce heavy metals from landfill soil.

The environmental monitoring of air pollution in the Santa Cruz industrial district of Rio de Janeiro using a plant fertility model

In 2010, a steel company was established in Santa Cruz, Rio de Janeiro. In 2012, silver rain raised concerns about human and environmental impacts. In 2013, the steel company signed an Adjustment of Conduct Term (ACT). To evaluate air pollution in the vicinity of the steel company based on a plant fertility assay before and after ACT implementation. A pollen abortion assay was implemented using flower buds of Bauhinia forficata in 2013 and Delonix regia in 2015. Sites over 5 km from the steel company, highways, and tunnels were classified as unexposed; sites 5 km from highway/tunnel were classified as exposed to other sources; and sites 5 km from the steel company were classified as exposed. Random plant collection occurred during the dry and rainy seasons (10 buds/site and 300 cells/slide). Aborted grains were analyzed using a 400-fold magnification microscope. Statistical analyses were considered significant at the 5% level. In 2013 were collected flower buds in 27 sites (2 unexposed, 18 highway/tunnel-exposed, and 7 steel company-exposed); and 34 sites in 2015 (14 unexposed, 18highway/tunnel-exposed, and 2 steel company-exposed). In both years, the mean pollen abortion was significantly higher in the dry season for sites exposed to highway/tunnel (p < 0.001) and the steel company (p = 0.005). In 2013, the mean pollen abortion was significantly higher in sites exposed to highway/tunnel compared to unexposed sites (p = 0.004) and in sites exposed to the steel company compared to sites exposed to highway/tunnel (p = 0.034). In 2015, compared to unexposed sites, the mean pollen abortion was significantly higher in sites exposed to highway/tunnel (p = 0.014) and the steel company (p < 0.001). Overall, compared to unexposed sites, the mean pollen abortion was 5.79-fold higher in sites exposed to the steel company and 4.08-fold higher in sites exposed to highway/tunnel. Compared to unexposed plants, greater air pollution effects occurred in plants exposed to the steel company before (2013) and after (2015)ACT implementation.

Effect of UV-C Irradiation on Greenhouse Whitefly, Trialeurodes vaporariorum (Hemiptera: Aleyrodidae)

Greenhouse whitefly, Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), is a serious pest of numerous crops grown in greenhouses and field-grown strawberry in yr-round production areas in California, USA. Problems with insecticide resistance have prompted the search for more sustainable methods for their management. Here, we applied UV-C light treatments nightly for 16 s (19.2 J m–2) over a 6-wk period to tomatoes infested with T. vaporariorum and compared numbers of adults, nymphs, and eggs with those on untreated plants. All life stages of T. vaporariorum were significantly lower on tomatoes treated nightly with UV-C compared with unexposed plants. Additionally, there was no significant difference in chlorophyll fluorescence activity. Our results indicate that nightly UV-C treatments significantly reduce T. vaporariorum populations and offer a potential non-chemical method for their management on tomato.

Effects of Methyl Salicylate on Host Plant Acceptance and Feeding by the Aphid Rhopalosiphum padi.

Methyl salicylate (MeSA) is a volatile shown to act as an inducer of plant defense against pathogens and certain herbivores, particularly aphids. It has been shown to have potential for aphid pest management, but knowledge on its mode of action is lacking, particularly induced plant-mediated effects. This study investigated the effects of exposing plants to MeSA on the host searching, host acceptance and feeding behavior of the bird cherry-oat aphid Rhopalosiphum padi. Barley plants were exposed to volatile MeSA for 24 h, after which biological effects were tested immediately after the exposure (Day 0), and then 1, 3 and 5 days after the end of the exposure. Aphid settling on MeSA-exposed plants was significantly reduced on days 0, 1 and 3, but not on day 5. In olfactometer tests, aphids preferred the odor of unexposed plants on days 1 and 3, but not on day 0 or 5. Analysis of volatiles from exposed and unexposed plants showed higher levels of MeSA from exposed plants, most likely absorbed and re-released from plant surfaces, but also specific changes in other plant volatiles on days 0, 1 and 3. High doses of MeSA did not affect aphid orientation in an olfactometer, but lower doses were repellent. Analysis of aphid feeding by Electronic penetration graph (EPG) showed that MeSA exposure resulted in resistance factors in barley plants, including surface factors and induced systemic factors in other tissues including the phloem. The results support the potential of MeSA as a potential tool for management of aphid pests.

Transcriptomic profiling of atrazine phytotoxicity and comparative study of atrazine uptake, movement, and metabolism in Potamogeton crispus and Myriophyllum spicatum

The accumulation of atrazine in sediments raises wide concern due to its potential negative effects on aquatic environments. Here we collected sediments and different submerged macrophytes to simulate natural shallow lakes and to measure atrazine levels and submerged macrophyte biomass. We determined gene expressions in submerged macrophytes treated with or without atrazine. We also examined atrazine concentrations and its metabolite structures in submerged macrophytes. When the initial concentration of atrazine in sediments ranged from 0.1 to 2.0 mg kg−1 dry weight (DW), atrazine levels in the pore water of the sediments ranged from 0.003 to 0.05 mg L−1 in 90 days. Atrazine did not show obvious long-term effects on the biomass of Potamogeton crispus and Myriophyllum spicatum (P > 0.05). On day 90, gene expressions related to cell wall in P. crispus were changed by atrazine phytotoxicity. Moreover, the decrease in the number genes controlling light-harvesting chlorophyll a/b-binding proteins verified the toxic effects of atrazine on the photosynthesis of M. spicatum. Compared with unexposed plants on day 90, ribosome pathway was significantly enriched with differentially expressed genes after submerged macrophytes were exposed to 2.0 mg kg−1 DW atrazine (P < 0.05). In addition, shoots and roots of P. crispus and M. spicatum could absorb the equal amount of atrazine (P > 0.05). Once absorbed by submerged macrophytes, atrazine was degraded into 1-hydroxyisopropylatrazine, hydroxyatrazine, deethylatrazine, didealkylatrazine, cyanuric acid, and biuret, and some of its metabolites could conjugate with organic acids, cysteinyl β-alanine, and glucose. This study establishes a foundation for aquatic ecological risk assessments and the phytoremediation of atrazine in sediments.

Assessment of pollution at the former uranium waste dumpsite near kaji-Say Village/Kyrgyzstan: a genetic and physiological investigation

ABSTRACT Kyrgyzstan still suffers from the past practices of radioactive industry operated by the Soviet Union that caused significant impact on ecosystems in this region, especially related with storage of uranium in inadequate conditions. There are at least 50 abandoned sites used as radioactive waste dumps in the country. Due to the pressure of natural and anthropogenic reasons, the structural foundations of mine waste dumps are gradually losing their integrities. Here, particular interest of our research is to reveal current state of radioactive contamination and to make evaluation on the radiological impacts of pollution caused by uranium mine waste dump, one is situated near Kaji-Say Village in Issyk Kul Region-Kyrgyzstan. In this study, the leaf, stem, and root parts of Perovskia abrotanoides Kar. and their co-located soils as study materials collected from five different localities were used for investigation of existent alterations on element uptake and genetic material in the plant using ICP-MS and ISSR marker technique. Also, radioactivity readings were recorded using Geiger counter. The data showed that the levels of radiation (in mR/h) were found to be significantly high in comparison with normal acceptable limits. Uptake patterns of certain elements in P. abrotanoides grown in the uranium waste dump site were modified extensively as reductions and increments due to strong radioactive leakage in comparison with the control. Also, the results indicated that changes in ISSR profiles from exposed plant leaf samples included variation in band intensities, losses of normal bands, and the appearances of new bands compared to unexposed (control) plant leaf sample. Considering people living around the area where the research was conducted, the consequences of contamination as our data suggest could cause health problems through radioactive leakage.

Ultraviolet-B induced changes in Mentha aquatica (a medicinal plant) at early and late vegetative growth stages: Investigations at molecular and genetic levels

Ultraviolet-B radiation (UV-BR) is a significant factor affecting plant growth and function. The present study was conducted to examine the effect of UV-BR on the oxidative metabolism, glandular trichomes, mesophyll cells, and the production of phytochemicals in leaf tissues of water mint (Mentha aquatica) at two vegetative (early and late) growth stages. With this aim, the plants were exposed to prolonged periods of UV-BR (2 h or 4 h daily) for three weeks at these growth stages. Physiological, biochemical, morphological, ultrastructural, and molecular investigations showed that UV-BR had divergent consequences on water mint. Biomass and photosynthetic pigments were reduced in the UV-BR-exposed plants compared with the unexposed plants. Conversely, UV-BR improved the oxidative metabolism, quantity of glandular trichomes, production of phytochemicals, and expression level of the candidate genes involved in terpene biosynthesis process at both the growth stages. In addition to these, UV-BR modified the chemical composition of volatile oils and the chloroplast ultrastructure in mesophyll cells. However, the rate of alterations in the surveyed parameters differed between the early and late vegetative stages. Plants were more sensitive to UV-BR at the early vegetative stage than at the late vegetative stage. The considered variables were found to be correlated under the UV-BR treatments at the different growth stages. Hence, it can be concluded that the UV-BR affects the production of phytochemicals, as well as the biosynthetic pathways involved, in water mint at the growth stages studied.

Male Colorado potato beetles alter search behavior in response to prior female presence on potato plants

For Colorado potato beetle, an integrated approach including semiochemicals and other nonpesticidal tactics is essential to sustainable management. A volatile aggregation pheromone produced by male adult beetles is attractive to both females and males. Yet earlier research also indicates that males respond to a yet-unidentified female-produced sex pheromone. We investigated male Colorado potato beetle behavior on potato plants that had been exposed to females only, males only, mixed-sex groups, or no beetles (clean plants). During observation, these plants hosted no beetles except for the single experimental male beetle. These males (previously mated or unmated) responded very differently to female-exposed plants, spending longer time on these plants, undertaking characteristic active searching behavior, exploring more leaves per plant, and moving more rapidly between leaves, compared to male-exposed or unexposed plants. When presented with a three-way choice, males spent about five times longer on the female-exposed foliage, compared to either male-exposed or clean leaves. Searching parameters differed between mated and unmated males, but both showed similar reactions to female-exposed plants; there was little to no statistical interaction between male mated condition and plant treatment. Results strongly indicate the presence of a persistent female-produced pheromone significantly influencing male searching behavior and between-plant movement.

Electromagnetic Radiation From Electronics Does Affect Plant Growth

Global warming is becoming an increasingly prominent issue. It is commonly disputed whether electronics and the radiation they emit are harmful towards the growth of organisms. As this cannot be tested on a human, we chose plants which are a key element of Earth. To be specific, this research was conducted on basil plants. The purpose of this experiment is to find out if electromagnetic (EM) radiation from electronics affects plant growth. After experimentation, it can be concluded that EM radiation did affect basil plant growth. The plants exposed to EM radiation were taller, thinner, and a much lighter shade of green compared to the unexposed plants. With the help of this experiment, the effects of EM radiation on the growth of organisms can be seen and studied. Further study is necessary to determine if the EM radiation affected the plants on a molecular level, as well as understand how they adapt or if they die. This research can be used to determine the potential detrimental effects that electronics can have on living organisms and the environment to eventually help create a solution to reduce or eliminate this harm.

Enhancement of Pathogen Resistance in Common Bean Plants by Inoculation With Rhizobium etli.

Symbiotic Rhizobium-legume associations are mediated by exchange of chemical signals that eventually result in the development of a nitrogen-fixing nodule. Such signal interactions are thought to be at the center of the plants’ capacity either to activate a defense response or to suppress the defense response to allow colonization by symbiotic bacteria. In addition, the colonization of plant roots by rhizobacteria activates an induced condition of improved defensive capacity in plants known as induced systemic resistance, based on “defense priming,” which protects unexposed plant tissues from biotic stress.Here, we demonstrate that inoculation of common bean plants with Rhizobium etli resulted in a robust resistance against Pseudomonas syringae pv. phaseolicola. Indeed, inoculation with R. etli was associated with a reduction in the lesion size caused by the pathogen and lower colony forming units compared to mock-inoculated plants. Activation of the induced resistance was associated with an accumulation of the reactive oxygen species superoxide anion (O2 −) and a faster and stronger callose deposition. Transcription of defense related genes in plants treated with R. etli exhibit a pattern that is typical of the priming response. In addition, R. etli–primed plants developed a transgenerational defense memory and could produce offspring that were more resistant to halo blight disease. R. etli is a rhizobacteria that could reduce the proliferation of the virulent strain P. syringae pv. phaseolicola in common bean plants and should be considered as a potentially beneficial and eco-friendly tool in plant disease management.

Mutagenic effects of ultraviolet (UV-C) irradiation on the anatomy of three species of Capsicum

UV radiant seedlings of Capsicum annuum, C. Chinenese and Capsicum frutescens were studied anatomically to observe the UV effects on the leaf epidermis, stem and root ultrastructures. While there is a higher percentage of stomatal index in the UV-exposed plants compared to the controlled, unexposed plants, there is no correlation in the stomatal density and stomatal size between the exposed and unexposed plants to the ultraviolet irradiation. There was also no correlation between the stomatal size and the stomatal density in both treatments (exposed and unexposed) in all the plants. Significant differences were observed in the stomatal index on both leaf surfaces between the exposed and controlled plants of C. frutescens and C. annuum. Cell walls of the stem and root wereobserved to be thicker in the UV-exposed plants.&#x0D; Bangladesh J. Sci. Ind. Res.54(2), 111-116, 2019

Ethylenediurea (EDU) pretreatment alleviated the adverse effects of elevated O3 on Populus alba “Berolinensis” in an urban area

Ethylenediurea (EDU) has been used as a chemical protectant against ozone (O3). However, its protective effect and physiological mechanisms are still uncertain. The present study aimed to investigate the changes of foliar visible injury, physiological characteristics and emission rates of volatile organic compounds (VOCs) in one-year-old Populus alba “Berolinensis” saplings pretreated with EDU and exposed to elevated O3 (EO, 120 μg/m3). The results showed that foliar visible injury symptoms under EO were significantly alleviated in plants with EDU application (p < 0.05). Under EO, net photosynthetic rate, the maximum photochemical efficiency of PSII and the photochemical efficiency of PSII of plants pretreated with 300 and 600 mg/L EDU were similar to unexposed controls and significantly higher compared to EO-stressed plants without EDU pretreatment, respectively. Malondialdehyde content was highest in EO without EDU and decreased significantly by 14.9% and 21.3% with 300 and 600 mg/L EDU pretreatment, respectively. EDU pretreatment alone increased superoxide dismutase activity by 10-fold in unexposed plants with further increases of 88.4% and 37.5% in EO plants pretreated with 300 and 600 mg/L EDU pretreatment, respectively (p < 0.05). Abscisic acid content declined under EO relative to unexposed controls with the effect partially reversed by EDU pretreatments. Similarly, VOCs emission rate declined under EO relative to unexposed plants with a recovery of emission rate observed with 300 and 600 mg/L EDU pretreatment. These findings provided significant evidence that EDU exerted a beneficial effect and protection on the tested plants against O3 stress.

Interaction of simulated acid rain and seed gall nematode Anguina tritici on wheat

In the present study, Interaction of different doses of SAR (pH 3.0, 4.0 and 5.0) with different inoculum levels of A. tritici showed varied responses on wheat plant. Both SAR and A. tritici interacted antagonistically. The wheat plants inoculated with lower inoculum levels (2,500, and 5,000) and exposed with lower acidity level (5.0) were not affected in terms of plant growth, yield, photosynthetic pigments, seed carbohydrate, seed protein and leaf epidermal characteristics compared to un-inoculated and un-exposed plant. While, as acidity levels (pH 4.0 and 3.0) were increased the suppressions in all above parameters were increased. However, nematodes were killed in all the doses of SAR.

Herbivores avoid host plants previously exposed to their omnivorous predator Macrolophus pygmaeus

Herbivorous arthropods use various cues to choose suitable host plants. We investigated whether three species of herbivores use cues associated with their omnivorous predator Macrolophus pygmaeus to select host plants. Earlier, we found that this omnivore induces plant defences which decreased the performance of two of the herbivores, i.e. the spider mite Tetranychus urticae and the western flower thrips Frankliniella occidentalis, whereas the green peach aphid Myzus persicae was not affected. Hence, the spider mite and thrips were expected to avoid plants that were previously exposed to M. pygmaeus because of their lower quality, and the aphid was not expected to avoid exposed plants because they were of equal quality as unexposed plants. However, the cues left behind by M. pygmaeus may also be indicative of predation risk, in which case all three herbivores were expected to avoid exposed plants. Spider mites and western flower thrips preferred clean plants over plants that had previously been exposed to M. pygmaeus, but no longer harboured this omnivore. Aphids showed no preference, in agreement with their performance, but not in agreement with reducing predation risk. We furthermore showed that the preference of spider mites and thrips for clean plants increased through time. Higher proportions of aphids left plants previously exposed to M. pygmaeus than clean plants through time. Hence, omnivorous predators can decrease herbivore densities on plants not only by killing them but also by indirectly affecting herbivore host plant selection.

Effects of the exposure of TiO2 nanoparticles on basil (Ocimum basilicum) for two generations

There is a lack of information about the transgenerational effects of titanium dioxide nanoparticles (nano-TiO2) in plants. This study aimed to evaluate the impacts of successive exposure of nano-TiO2 with different surface properties to basil (Ocimum basilicum). Seeds from plants exposed or re-exposed to pristine, hydrophobic, or hydrophilic nano-TiO2 were cultivated for 65 days in soil unamended or amended with 750 mg·kg−1 of the respective particles. Plant growth, concentration of titanium and essential elements, as well as content of carbohydrates and chlorophyll were evaluated. There were no differences on Ti concentration in roots of plants sequentially exposed to pristine or hydrophobic nano-TiO2, or in roots of plants exposed to the corresponding particle, only in the second cycle. However, sequential exposure to hydrophilic particles resulted in 65.2% less Ti in roots, compared to roots of plants exposed the same particles, only in the second cycle. The Ti concentrations in shoots were similar in all treatments. On the other hand, pristine and hydrophilic particles reduced Mg in root by 115% and 81%, respectively, while pristine and hydrophobic particles reduced Ni in shoot by 84% and 75%, respectively, compared to unexposed plants in both cycles. Sequential exposure to pristine nano-TiO2 increased stomatal conductance (214%, p ≤ 0.10), compared to plants that were never exposed. Hydrophobic and hydrophilic nano-TiO2 reduced chlorophyll b (52%) and total chlorophyll (30%) but increased total sugar (186%) and reducing sugar (145%), compared to unexposed plants in both cycles. Sequential exposure to hydrophobic or hydrophilic nano-TiO2 resulted in more adverse effects on photosynthesis but in positive effects on plant growth, compared to pristine nano-TiO2.

Weeding volatiles reduce leaf and seed damage to field-grown soybeans and increase seed isoflavones

Field experiments were conducted over 3 years (2012, 2013, and 2015), in which half of the young stage soybean plants were exposed to volatiles from cut goldenrods three times over 2–3 weeks, while the other half remained unexposed. There was a significant reduction in the level of the total leaf damage on exposed soybean plants compared with unexposed ones. In 2015, the proportion of damage to plants by Spodoptera litura larvae, a dominant herbivore, was significantly less in the exposed field plots than in the unexposed plots. Under laboratory conditions, cut goldenrod volatiles induced the direct defenses of soybean plants against S. litura larvae and at least three major compounds, α-pinene, β-myrcene, and limonene, of cut goldenrod volatiles were involved in the induction. The number of undamaged seeds from the exposed plants was significantly higher than that from unexposed ones. Concentrations of isoflavones in the seeds were significantly higher in seeds from the exposed plants than in those from the unexposed plants. Future research evaluating the utility of weeding volatiles, as a form of plant–plant communications, in pest management programs is necessary.

The role of phytophagy by predators in shaping plant interactions with their pests

ABSTRACTZoophytophagy is common among predacious arthropods, but research on their role in plant-herbivore interactions is generally focused on predation effects whereas their phytophagy is largely neglected. Our recent study revealed the ability of zoophytophagous predators to induce defense related traits and to affect herbivore performance apart from predation through the plant. Additionally, we show here that predator-exposed plants suffer less damage compared to unexposed plants. Thus, zoophytophagous organisms likely shape community structure by both their predation on herbivores and their phytophagy. Here, we consider zoophytophagous predators as plant vaccination factors and outline how their dual role in affecting herbivores may impact their use in biological pest control. Because plant responses to phytophagy and phytopathogens are known to interact, zoophytophagous predators may also affect plant-pathogen interactions. When we consider these indirect interactions with different plant pest organisms, we will likely better understand the ecology of the complex relationships among plants, herbivores and predators. Moreover, a comprehensive knowledge on the effects of the phytophagy of predators in these ecological interactions will potentially allow us to enhance sustainability in pest control.

Application of liquid chromatography/electrospray ionization ion trap tandem mass spectrometry for the evaluation of global nucleic acids: methylation in garden cress under exposure to CuO nanoparticles.

A full understanding of the biological impact of nanomaterials demands analytical procedures suitable for the detection/quantification of epigenetic changes that occur in the exposed organisms. Here, the effect of CuO nanoparticles (NPs) on global methylation of nucleic acids in Lepidium sativum was evaluated by liquid chromatography/ion trap mass spectrometry. Enhanced selectivity toward cytosine-containing nucleosides was achieved by using their proton-bound dimers formed in positive electrospray ionization (ESI(+)) as precursor ions for multiple reaction monitoring (MRM) quantification based on one or two ion transitions. Plants were exposed to CuO NPs (0-1000 mg L(-1)); nucleic acid extracts were washed with bathocuproine disulfate; nucleosides were separated on a Luna C18 column coupled via ESI(+) to an AmaZon SL mass spectrometer (Bruker Daltonics). Cytidine, 2´-deoxycytidine, 5-methylcytidine, 5-methyl-2´-deoxycytidine and 5-hydroxymethyl-2´-deoxycytidine were quantified by MRM based on MS(3) ([2M+H](+)/[M+H](+)/[M+H-132](+) or [M+H-116](+)) and MS(2) ([2M+H](+)/[M+H](+) ). Bathocuproine disulfate, added as Cu(I) complexing agent, allowed for elimination of [2M+Cu](+) adducts from the mass spectra. Poorer instrumental detection limits were obtained for MS(3) (20-120 fmol) as compared to MS(2) (9.0-41 fmol); however, two ion transitions helped to eliminate matrix effects in plant extracts. The procedure was tested by analyzing salmon sperm DNA (Sigma) and applied for the evaluation of DNA and RNA methylation in plants; in the absence of NPs, 13.03% and 0.92% methylated cytosines were found in DNA and RNA, respectively; for NPs concentration >50 mg L(-1), DNA hypomethylation was observed with respect to unexposed plants. RNA methylation did not present significant changes upon plant exposure; 5-hydroxymethyl-2´-deoxycytidine was not detected in any sample. The MRM quantification proposed here of cytosine-containing nucleosides using their proton-bound homo-dimers as precursor ions proved its utility for the assessment of global methylation of DNA and RNA in plants under stress imposed by CuO NPs. Detection of copper adducts with cytosine-containing ions, and their elimination by washing extracts with Cu(I) chelator, calls for further investigation.