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Genistein and naringenin, plant phenolic compounds, are recognized for their health benefits and role in plant defense against herbivores. However, little research exists on how these compounds affect aphid feeding, particularly that of the black bean aphid (Aphis fabae Scopoli) (Hemiptera: Aphididae), a major pest. This study aimed to evaluate the effects of genistein and naringenin, applied in vitro at different concentrations, on the feeding behavior of A. fabae. Statistical analysis indicated that both the type and concentration of flavonoids significantly influenced aphid stylet activity, salivation, and ingestion. Higher concentrations of both compounds hindered feeding behavior. A longer initial probe was observed on gels containing the studied flavonoids. Genistein at 0.1% completely inhibited salivation while at 0.01%, it reduced the duration of salivation activities. Both compounds also delayed the start and lengthened the duration of active ingestion, though A. fabae tolerated genistein better than naringenin. Naringenin's effects on feeding behavior were more pronounced at higher concentrations. These findings suggest that genistein and naringenin could be valuable chemicals to protect plants from aphids in a sustainable and environmentally friendly way. [ABSTRACT FROM AUTHOR]

Guelder rose (Viburnum opulus L.) is known for its health benefits. V. opulus contains phenolic compounds (flavonoids and phenolic acids), a group of plant metabolites with wide biological activities. They are good sources of natural antioxidants in human diets owing to their prevention of the oxidative damage responsible for many diseases. In recent years, observations have shown that an increase in temperature can change the quality of plant tissues. So far, little research has addressed the problem of the common impact of temperature and place of occurrence. Towards a better understanding of phenolics concentration that could indicate their potentials as therapeutic agents and towards predicting and controlling the quality of medicinal plants, the aim of this study was to compare phenolic acids and flavonoids content in the leaves of cultivation and wild collection V. opulus, and to examine the impacts of temperature and place of occurrence on their content and composition. Total phenolics were determined using the spectrophotometric method. Phenolic composition of V. opulus was determined using high-performance liquid chromatography (HPLC). The following hydroxybenzoic acids there were identified: gallic, p-hydroxybenzoic, syringic, salicylic, benzoic, as well as hydroxycinnamic acids: chlorogenic, caffeic, p-coumaric, ferulic, o-coumaric and t-cinnamic. The analysis of extracts from V. opulus leaves has indicated the presence of the following flavonoids: flavanols: (+)-catechin and (−)-epicatechin; flavonols: quercetin, rutin, kaempferol, myricetin; and flavones: luteolin, apigenin and chrysin. The dominant phenolic acids were p-coumaric and gallic acids. The major flavonoids found in V. opulus leaves were myricetin and kaempferol. Temperature and plant location affected the concentration of tested phenolic compounds. The present study shows the potential of naturally grown and wild V. opulus for the human. [ABSTRACT FROM AUTHOR]

Aphis fabae Scop. is phloem-feeding insect that cause substantial damage to horticulare and agriculture worldwide due to feeding - related damage and the transmission of economically important plant viruses. These aphids cause a detrimental effects in attacked organs, like depletion of photoassimilates. Insect feeding can among others reduced chlorophyll catabolism. In the present investigations we determined the chlorophyll a and b levels (SPAD readings) in uninfested leaves and in Aphis fabae-infested leaves of Viburnum opulus shrubs, wild plants and garden variety, which were grown in green areas around Siedlce, east central Poland. Feeding by A. fabae affected chlorophyll a + b level. The insect feeding reduces the concentration of photosynthetic pigment in the infested shrubs. The level of chlorophyll in plants occupied by aphids was clearly lower than the level in plants where aphids were not found. We also found that chlorophyll levels increased with the progress of growing season, the level of chlorophyll differed between date of survey, being higher for the latest survey (mid-June) and that the place where the plant is located is important, wild V. opulus have slightly more level of chlorophyll compared to garden ones. Chlorophyll level might be useful as an indicator of plant responses to aphid damage. [ABSTRACT FROM AUTHOR]

Changes in the level of oxidative stress markers—superoxide anion radical ( O 2 − ), hydrogen peroxide (H2O2) and malondialdehyde (MDA) and the activity of antioxidant enzymes—superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in the black bean aphid occurring on the primary host (viburnum plants) were studied. Among the aphid morphs, the lowest contents of O 2 − , H2O2 and MDA were noted for winged adults (alatae), which were also characterized by the highest activity of antioxidant enzymes. These metabolic features indicate the adaptation of winged morphs to the colonization of new host plants. During spring migration, an increase in the content of oxidative stress markers and antioxidant enzyme activities in wingless females (fundatrigeniae) was observed. The significance of the biochemical adaptation of the black bean aphid to its winter host is discussed. [ABSTRACT FROM AUTHOR]

We studied the effect of the cereal aphid (the bird cherry-oat aphid Rhopalosiphum padi L. and grain aphid Sitobion avenae F.) infestations on the oxidative damages of protein in the maize (Zea mays L., cultivar 'Touran') seedlings. We found that the content of protein thiols and protein bound carbonyls were dependent from study factors: time of feeding, the number of aphids and species. In relation to uninfested plants (control), prolonged insect (R. padi and S. avenae) feeding (24-96 h post infestations) was linked to depletion in levels of protein thiols in foliar tissues of maize genotype and accumulation after 96 h post infestations in maize seedlings investigated by higher number of aphids, protein bound carbonyls. Our results indicated that the biotic stress factors, including aphids evoke the oxidation of protein in the maize. The stronger protein damages occurred in the maize seedlings infested with oligophagous R. padi females. [ABSTRACT FROM AUTHOR]

The rose-grass aphid (Methopolophium dirhodum Walk.) is a major pest of maize (Zea mays L.), but little is known about the biochemical interactions between M. dirhodum and its host plant. Thiol compounds and glutathione S-transferase (GST) play a crucial role in the defense responses of maize to biotic stress factors, including aphids. The purpose of this research was to evaluate the impact of M. dirhodum herbivory on the total thiol (TT), protein bound thiol (PT), reduced glutathione (GSH) and oxidized glutathione (GSSG) contents as well as the activity of GST in three varieties of Z. mays (Złota Karłowa, Ambrozja and Płomyk), that were classified as aphid-susceptible, aphid-relatively resistant and aphid-resistant, respectively. The earliest and strongest aphid-triggered alterations in the levels of TT, PT and GSH, and the greatest induction of GST activity, were recorded in the resistant Płomyk seedlings in relation to the relatively resistant Ambrozja and the susceptible Złota Karłowa. [ABSTRACT FROM AUTHOR]

Purpose. The aim of the study was to evaluate the effects of a decrease in hold size, change in the safety rope protocol, and rest period shortening on heart rate (HR), heart rate variability (HRV), pre-climb anxiety, and perceived workload in sport rock climbers under laboratory settings. Methods. A total of 12 intermediate sport rock climbers were recruited. The participants completed 2 routes of different climbing difficulty. They repeated the difficult route with a short 5-minute rest period 3 times and repeated the same route with a change to lead climb. HR, HRV, anxiety level (Competitive State Anxiety Inventory-2 Revised), and climbing workload (NASAclimbing questionnaire) were measured. Results and conclusions. It was lead climb that elicited the most noticeable psychophysical response in the intermediate climbers. Prior to the climb, the performers exhibited marked sympathetic activation and higher cognitive anxiety. Climbing HRpeak was correlated with physical workload, psychological demand, and increasing fatigue; hence, it can be considered a variable that reflects the accumulative psychophysiological stress. NASAclimbing score effectively reflected differences in physical load (physical demand - strength and endurance) and psychological load (higher mental demand, temporal demand, and satisfaction level) during climbing. [ABSTRACT FROM AUTHOR]

The purpose of this report was to evaluate the expression patterns of selected glutathione transferase genes (gst1, gst18, gst23 and gst24) in the tissues of two maize (Zea mays L.) varieties (relatively resistant Ambrozja and susceptible Tasty Sweet) that were colonized with oligophagous bird cherry-oat aphid (Rhopalosiphum padi L.) or monophagous grain aphid (Sitobion avenae L.). Simultaneously, insect-triggered generation of superoxide anion radicals (O2•−) in infested Z. mays plants was monitored. Quantified parameters were measured at 1, 2, 4, 8, 24, 48 and 72 h post-initial aphid infestation (hpi) in relation to the non-infested control seedlings. Significant increases in gst transcript amounts were recorded in aphid-stressed plants in comparison to the control seedlings. Maximal enhancement in the expression of the gst genes in aphid-attacked maize plants was found at 8 hpi (gst23) or 24 hpi (gst1, gst18 and gst24) compared to the control. Investigated Z. mays cultivars formed excessive superoxide anion radicals in response to insect treatments, and the highest overproduction of O2•− was noted 4 or 8 h after infestation, depending on the aphid treatment and maize genotype. Importantly, the Ambrozja variety could be characterized as having more profound increments in the levels of gst transcript abundance and O2•− generation in comparison with the Tasty Sweet genotype. [ABSTRACT FROM AUTHOR]

The aim of the present study was to compare ascorbate (ASA) content and ascorbate peroxidase (APX) activity in seedlings of the less susceptible triticale cultivar Witon and the more susceptible triticale cultivar Tornado after infestation by the grain aphid Sitobion avenae (F). and the bird cherry-oat aphid Rhopalosiphum padi (L.). The content of ASA in triticale seedlings slightly decreased after 24 hrs of infestation by cereal aphids, but prolonged feeding (48 hrs and 72 hrs) resulted in significant losses in ASA dependent on cultivar and aphid species. The aphid infestation caused an increase in APX activity in triticale tissues throughout the test period. The aphid herbivores induced APX activity to a higher level in a less susceptible cultivar than in a more susceptible one. The oligophagous species R. padi caused a higher decrease of ASA and stronger induction of APX activity in tested triticale than the monophagous species S. avenae. The experiments carried out indicate that ascorbate and ascorbate peroxidase may play a significant role in the defense mechanism of aphid infested triticale. [ABSTRACT FROM AUTHOR]

Flavonoids play an important role in interactions of plants with the environment. Liquid chromatography (HPLC) was used to determine the flavonoid profiles (especially luteolin, tricin, and chrysoeriol glycosides), their total concentrations, and changes in the amounts of eight flavones found in the aerial parts of alfalfa (Medicago sativa L.) (Fabaceae) Radius cv., uninfested and infested by the pea aphid (Acyrthosiphon pisum Harris) (Homoptera: Aphididae). It was shown that both control and infested green aerial parts of alfalfa plants had similar flavonoid profiles. The dominant flavonoid of alfalfa was compound 7-O-[2-O-feruloyl-ß-D-glucuronopyranosyl(1→2)-O-ß-D-glucuronopyranosyl]-4'-O-ß-D-glucuronopyranosideluteolin. Compound 7-O-{2'-O-feruloyl-[ß-D-glucuronopyranosyl(1→3)]-O-ß-D- glucuronopyranosyl(1→2)-O-ß-D-glucuronopyranosidetricin was present in the smallest amounts. The total concentration of flavones was rather high and ranged from 11.13 to 12.34 mg/g d.m., but there were no significant differences between uninfested and infested alfalfa plants. There was a correlation between the concentration of flavonoid glycosides in the alfalfa plants and pea aphid abundance. Pea aphid daily fecundity per female was affected by luteolin, tricin, and chrysoeriol glycosides and the level of chrysoeriol glycosides affected ingestion of xylem sap by the aphid. This finding may indicate that the studied flavonoid glycoside forms are biologically active in alfalfa -- A. pisum interactions. [ABSTRACT FROM AUTHOR]

The effect of some species of the Fabaceae family (the pea Pisum sativum L., broad bean Vicia faba L. and vetch V. sativa L.) on biochemical markers of oxidative stress within tissues of the pea aphid, Acyrthosiphon pisum Harris (Homoptera, Aphididae), has been studied. The highest concentration of superoxide anion radical (O2-), hydrogen peroxide (H2O2) and lipid peroxidation products thiobarbituric acid reactive substances (TBARS) was recorded for morphs that fed on the broad bean. The opposite tendency was observed for the level of total thiols, that were the highest for insects reared on the pea. Among the studied aphid morphs, the highest concentration of superoxide anion and hydrogen peroxide was noted for the wingless females whereas TBARS content was the highest within the winged migrant tissues. Different results were obtained for the total thiols, where apterae as well as migrants reared on the tested plants, had comparable content of these compounds. Our experiments indicate that oxidative stress may play an important role in interactions between the pea aphid and their host plants. [ABSTRACT FROM AUTHOR]

We studied the development and feeding behaviour of the pea aphid, Acyrthosiphon pisum (Harris) (Homoptera: Aphididae), on the Radius and Sapko alfalfa ( Medicago sativa L.) (Fabaceae) cultivars. Three saponins and flavones were identified in the alfalfa cultivars after thin layer chromatography separation. Cultivar Radius differed from Sapko in that it had a higher level of saponins, including zanhic acid tridesmoside and 3-GlcA,28-AraRhaXyl medicagenic acid glycoside. The flavones identified, including 7- O-β-D-glucuronopyranosyl-4′- O-[2′- O-E-feruloyl- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside] apigenin, 7- O-{2- O-E-feruloyl-[β-D-glucuronopyranosyl(1→3)]- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside} apigenin, and 4′- O-[2′- O-E-feruloyl- O-β-D-glucuronopyranosyl(1→2)- O-β-D-glucuronopyranoside] apigenin, occurred in tissues of both alfalfa cultivars. However, cv. Radius had very low mean flavonoid concentrations in comparison to cv. Sapko. Pea aphids that fed on cv. Radius plants showed a reduction in reproduction and survival. The aphid pre-reproductive period on cv. Radius was prolonged and the reproductive and post-reproductive periods on cv. Radius were reduced, compared to those on cv. Sapko. Cultivar Radius also negatively influenced aphid probing behaviour. This was especially the case during the initial period of the pathway phase. The results suggested that alfalfa cv. Radius, which had a higher level of saponins and a lower level of flavonoids, was less accepted by the pea aphid. [ABSTRACT FROM AUTHOR]

Thioredoxins (Trxs) and thioredoxin reductases (TrxRs) encompass a highly complex network involved in sustaining thiol-based redox homeostasis in plant tissues. The purpose of the study was to gain a new insight into transcriptional reprogramming of the several genes involved in functioning of Trx/TrxR system in maize (Zea mays L.) seedlings, exposed to the bird cherry-oat aphid (Rhopalosiphum padi L.) or the rose-grass aphid (Metopolophium dirhodum Walk.) infestation. The biotests were performed on two maize genotypes (susceptible Złota Karłowa and relatively resistant Waza). The application of real-time qRT-PCR technique allowed to identify a molecular mechanism triggered in more resistant maize plants, linked to upregulation of thioredoxins-encoding genes (Trx-f, Trx-h, Trx-m, Trx-x) and thioredoxin reductase genes (Ftr1, Trxr2). Significant enhancement of TrxR activity in aphid-infested Waza seedlings was also demonstrated. Furthermore, we used an electrical penetration graph (EPG) recordings of M. dirhodum stylet activities in seedlings of the two studied maize varieties. Duration of phloem phase (E1 and E2 models) of rose-grass aphids was about three times longer while feeding in Waza plants, compared to Złota Karłowa cv. The role of activation of Trx/TrxR system in maintaining redox balance and counteracting oxidative-induced damages of macromolecules in aphid-stressed maize plants is discussed. [ABSTRACT FROM AUTHOR]

Prior experiments illustrated reactive oxygen species (ROS) overproduction in maize plants infested with bird-cherry-oat (Rhopalosiphum padi L.) aphids. However, there is no available data unveiling the impact of aphids feeding on oxidative damages of crucial macromolecules in maize tissues. Therefore, the purpose of the current study was to evaluate the scale of oxidative damages of genomic DNA, total RNA and mRNA, proteins, and lipids in seedling leaves of two maize genotypes (Złota Karłowa and Waza cvs—susceptible and relatively resistant to the aphids, respectively). The content of oxidized guanosine residues (8-hydroxy-2′-deoxyguanosine; 8-OHdG) in genomic DNA, 8-hydroxyguanosine (8-OHG) in RNA molecules, protein carbonyl groups, total thiols (T-SH), protein-bound thiols (PB-SH), non-protein thiols (NP-SH), malondialdehyde (MDA) and electrolyte leakage (EL) levels in maze plants were determined. In addition, the electrical penetration graphs (EPG) technique was used to monitor and the aphid stylet positioning and feeding modes in the hosts. Maize seedlings were infested with 0 (control), 30 or 60 R. padi adult apterae per plant. Substantial increases in the levels of RNA, protein and lipid oxidation markers in response to aphid herbivory, but no significant oxidative damages of genomic DNA, were found. Alterations in the studied parameters were dependent on maize genotype, insect abundance and infestation time. [ABSTRACT FROM AUTHOR]

Juglone (JU; 5-hydroxy-1,4-naphthoquinone) is an allelochemical synthetized by a wide range of Juglandaceae members. This compound evokes a wide array of detrimental effects in susceptible acceptor plants, including growth inhibition and impairments in the course of biochemical and physiological processes. Therefore, juglone may be considered as a potential bioherbicide in weed control in cereal crops. The purpose of our study was to determine the influence of JU treatment on the content of superoxide anion radical (O2 •-- ) - sensitive and early marker of oxidative stress, and the activity of superoxide dismutase (SOD) - enzyme that functions as a crucial component of the first line antioxidative defense in seed tissues. In the study we tested seeds of four selected plant species of cereal agrosystem: corn poppy (Papaver rhoeas L.), corn cockle (Agrostemma githago L.), spring wheat (Triticum aestivum L., cv. Nawra), and spring oat (Avena sativa L., cv. Maczo). Additionally, the allelopathic influence of JU on seed germination of the studied plant species was investigated. The seeds were exposed to three examined juglone concentrations: 0.001, 0.1, and 10 mM (4% methanol- deionized water solutions), whereas the control seeds were treated with aqueous methanolic solutions (4%). Obtained results evidenced much more severe suppression of germination process and robust generation of superoxide anion radical in the tested weeds, compared to the cereals, and the crucial role of superoxide dismutase in limiting the juglone-induced oxidative stress in the studied seeds. [ABSTRACT FROM AUTHOR]