Natural Plant Protection Research Articles

Analysis of glycoalkaloid distribution in the tissues of mealworm larvae (Tenebrio molitor)

Solanine (SOL) and chaconine (CHA) are glycoalkaloids (GAs) produced mainly by Solanum plants. These plant secondary metabolites affect insect metabolism; thus, they have the potential to be applied as natural plant protection products. However, it is not known which GA concentration induces physiological changes in animals. Therefore, the aim of this study was to perform a quantitative analysis of SOL and CHA in the larvae of Tenebrio molitor using LC‒MS to assess how quickly they are eliminated or metabolised. In this experiment, the beetles were injected with 2 μL of 10−5 M SOL or CHA solution, which corresponds to a dosage range of 0.12–0.14 ng/mg body mass. Then, 0.5, 1.5, 8, and 24 h after GA application, the haemolymph (H), gut (G), and the remainder of the larval body (FB) were isolated. GAs were detected in all samples tested for 24 h, with the highest percentage of the amount applied in the FB, while the highest concentration was measured in the H sample. The SOL and CHA concentrations decreased in the haemolymph over time, while they did not change in other tissues. CHA had the highest elimination rate immediately after injection, while SOL slightly later. None of the GA hydrolysis products were detected in the tested samples. One possible mechanism of the detoxification of GAs may be oxidation and/or sequestration. They may be excreted by Malpighian tubules, with faeces or with cuticles during moulting. The results presented are significant because they facilitate the interpretation of studies related to the effects of toxic substances on insect metabolism.

Lithos crop protect: Food safety needs natural plant protection

Lithos crop protect: Food safety needs natural plant protection Here, we learn that Lithos Crop Protect works on greener agriculture thanks to EU innovation funding. The Austrian company Lithos Crop Protect has prevailed as one of the few selected companies and has been awarded an EU Accelerator grant. This European Innovation Council funding program supports small and medium-sized enterprises with innovative solutions that contribute to a better and more sustainable future. Lithos Crop Protect is working at full speed on just such a solution. There is only a limited amount of land available for agriculture. However, a growing population still needs a secure and high-quality food supply. While this balancing act requires effective pest control, conventional chemical products used to protect crops often come under heavy flak, and their use is increasingly restricted or outlawed. That’s why Lithos Crop Protect is working on natural solutions to this problem – such as its patented pheromone application, the first sprayable product of its kind worldwide.

Apocarotenoids are allosteric effectors of a dimeric plant glycosyltransferase involved in defense and lignin formation.

Glycosyltransferases are nature's versatile tools to tailor the functionalities of proteins, carbohydrates, lipids, and small molecules by transferring sugars. Prominent substrates are hydroxycoumarins such as scopoletin, which serve as natural plant protection agents. Similarly, C13-apocarotenoids, which are oxidative degradation products of carotenoids/xanthophylls, protect plants by repelling pests and attracting pest predators. We show that C13-apocarotenoids interact with the plant glycosyltransferase NbUGT72AY1 and induce conformational changes in the enzyme catalytic center ultimately reducing its inherent UDP-α-d-glucose glucohydrolase activity and increasing its catalytic activity for productive hydroxycoumarin substrates. By contrast, C13-apocarotenoids show no effect on the catalytic activity toward monolignol lignin precursors, which are competitive substrates. In vivo studies in tobacco plants (Nicotiana benthamiana) confirmed increased glycosylation activity upon apocarotenoid supplementation. Thus, hydroxycoumarins and apocarotenoids represent specialized damage-associated molecular patterns, as they each provide precise information about the plant compartments damaged by pathogen attack. The molecular basis for the C13-apocarotenoid-mediated interplay of two plant protective mechanisms and their function as allosteric enhancers opens up potential applications of the natural products in agriculture and pharmaceutical industry.

A New Biocontrol Tool to Fight Potato Late Blight Based on Willaertia magna C2c Maky Lysate.

Potato late blight (PLB) is one of the most destructive disease affecting potatoes. Late blight control relies almost exclusively on the use of chemical pesticides, including copper products, which are efficient but controversial due to their environmental toxicity. Societal pressure and the quest for more sustainable agriculture reinforce the need for natural plant protection products. To respond to this demand, we tested the lysate of the amoeba Willaertia magna C2c Maky on PLB. This active substance exhibits plant protection properties against grape downy mildew thanks to a dual mode of action (plant elicitor and antifungal direct effect). We hypothesized that this active substance might also have an effect against other diseases caused by oomycetes on other crops, such as potato. In vitro, in planta, and in-field studies were conducted. The collected data demonstrate that the lysate of the amoeba Willaertia magna C2c Maky is able to elicit potato defenses, and direct fungicidal activity against Phytophtora infestans was observed. Proof of efficacy was first obtained in greenhouse, with up to 80% disease reduction, and confirmed in field trials. Formulated products provided up to 77% protection in field in the case of low infestation (28%) and up to 49% protection when the untreated plants were 100% destroyed. Willaertia magna C2c Maky was also able to significantly increase yield by up to 30% in field trials.

Urbanization hampers biological control of insect pests: A global meta-analysis

Biological control is a major ecosystem service provided by pest natural enemies, even in densely populated areas where the use of pesticides poses severe risks to human and environmental health. However, the impact of urbanization on this service and the abundance patterns of relevant functional groups of arthropods (herbivores, predators, and parasitoids) remain contested. Here, we synthesize current evidence through three hierarchical meta-analyses and show that advancing urbanization leads to outbreaks of sap-feeding insects, declining numbers of predators with low dispersal abilities, and weakened overall biological pest control delivered by arthropods. Our results suggest that sedentary predators may have the potential to effectively regulate sap-feeders, that are one of the most important pests in urban environments. A well-connected network of structurally diverse and rich green spaces with less intensive management practices is needed to promote natural plant protection in urban landscapes and sustainable cities.

Resource Use Efficiency of Natural Farming Systems in Low Hills of Himachal Pradesh

The present study aimed to investigate the resource use efficiency of natural farming systems in the low hills of Himachal Pradesh using the Cobb-Douglas production function. A sample of 120 farmers was selected using a simple random sampling technique. The regression coefficients of each input were estimated using Stata 13.1 software. The study revealed that the use of seed (5.03), natural plant protection (14.43) and labour (18.11) were found underutilized as the value of 'r' was more than one, whereas natural fertilizer (-11.62) was found over-utilized as the value of 'r' was less than one and needed to be increased 80.13, 93.07 and 94.48 per cent to produce at the optimum level of production. This might be due to the majority of the farmers being deprived of better extension services and lack of training for human capacity building. This study concluded that the resources should be used wisely to maximize returns. Government and other concerned stakeholders should give priority to providing efficient technical knowledge about good natural farming practices.

Effects of biological preparations on the predatory mite Phytoseiulus

The common spider mite Tetranychus urticae Koch is a dangerous pest. This pest occurs more frequently on cucumber crops than other pests and damages more than 200 other plant species, including aubergine, pepper, tomato, lemon, chrysanthemum, rose and carnation. The specific conditions of the protected environment allow greater use of biological agents for pest control. The modern concept of natural plant protection involves a combination of several birth control agents used to suppress pest populations. In this study, the authors studied the effect of biological preparations on the survival of the predatory mite Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae) under laboratory conditions. A laboratory evaluation was made of the effect of the biological preparations Bitoxybacillin, 1% and Fytoverm, 0.2%. These preparations significantly reduce acariphage numbers when released immediately after treatment. The predatory mite showed higher sensitivity in the variant with Fitoverm, 0.2%. Acariphage numbers decreased, but not significantly when plants were treated with Biovert (1%) and the fungus strain Metarhizium robertsii. Thus, plant treatment and acariphage release should be carefully regulated when phytoseiulus is released because of the adverse effects of bio preparations. The results confirm the potential use of biological practices combined with the predatory mite Phytoseiulus persimilis against the common spider mite Tetranychus urticae.

Eucalyptus staigeriana essential oil can control downy mildew in grapevine

Downy mildew (Plasmopara viticola) is the primary disease in viticulture worldwide, and your control requires synthetic fungicides applications to avoid quality and yield loss in the grapevines. However, alternatives to reduce synthetic fungicides are needed to ensure the consumer’s health and the environment. Essential oils (EOs) are amongst the most promising natural plant protection alternatives because of their antifungal properties on several crop diseases. The present study objective was to determine the effect of Eucalyptus staigeriana EO in vitro and in vivo against P. viticola. The EO exhibited the highest activity in vitro, inhibiting 90% of the incidence and severity of disease caused by P. viticola in leaves of grapevines in the greenhouse. In the field (in vivo), treatment with EO could not control the disease; however, treatment with EO in consortium with conventional treatment reduced approximately 50% of the incidence and more than 90% of the severity of downy mildew disease in leaves, decreasing the application of synthetic fungicides by 50%.

Essential Oil of Myrtus communis L. effects In Vitro and In Vivo Evaluation against Chickpea Blight (Ascochyta rabiei) Disease

In this study, (Myrtus communis L.) was explored in vitro and in vivo for controlling blight disease using two chickpea genotypes ILC 3279, INRA 199 and a local cultivar Bouazza. Blight caused by Ascochyta rabiei Pass. Lab. is major disease affecting chickpea production. To control this disease, chemical harmful fungicides are used hence, developing natural plant protection products as an alternative has become important regarding the environmental impact. The effect of essential oil (EO) extracted from myrtle leaves by hydrodistillation was evaluated on the growth of Ascochyta rabiei Pass. Lab. mycelium, by dilution method using chickpea culture medium added with 0, 200, 300, 500 and 1000 ppm. The radial growth of A. rabiei Pass.Lab. was inhibited at 40.9, 68.18 and 96.69% with 200, 300 and 500 ppm respectively. Myrtle essential oil used at 1000 ppm inhibited the fungus growth completely (100%). In vitro EO efficacy was investigated using detached leaflets method inoculated with 5 µl pathogen spore solution of 106 spores / ml concentration. Efficacy was investigated using 750 ppm EO solution. Disease (DS) Severity and disease incidence (DI) on detached leaflets were determined. Highest disease incidence was observed on Bouazza (100%) followed by ILC 3279 (84.28%) and INRA 199 (17.5%). Myrtle essential oil showed an efficacy in all cases and decreased significantly disease incidence for Bouazza, ILC 3279 and INRA 199 to 63.33, 56.66 and 16% respectively. Disease severity showed the same profile, Bouazza noted the highest rate followed by ILC 3279 and INRA 199 with 60, 40 and 21% respectively and EO showed a significant efficacy and reduced these disease severity rates to 52 32 and 18 %. The bioassay conducted in vivo under greenhouse conditions with plants including a negative control with any treatment and two other batches inoculated by hand held sprayer, a spore solution with a concentration of 106 spores/ ml and treated or not with myrtle EO. Disease incidence percentage (DIP) decreased significantly under common myrtle EO compared to control in INRA 199 and ILC 3279 for severity percent index (SPI) no significant difference was observed for all genotypes under Myrtus communis L. essential oil treatment effect. This study showed Myrtus communis L. essential oil efficacy on chickpea blight disease in vitro on fungal radial growth and in vivo either on deatached leaflets or whole plants under greenhouse condition. This natural product reduced significantly blight disease incidence and severity. And to control disease, myrtle essential oil extraction as fungicide is a promising alternative against this disease.

Status and prospects of plant protection from pests in megapolis

Goal. Conduct screening of modern data on the state of plant protection and its own studies of phytophagus pests of wood plants in the conditions of the metropolis of Ukraine.
 Methods. Analytical methods and faunistic screening of data literary sources are used on the issue of phytophagus pests of Ukraine.
 Results. The substantiation of the concept of preventive creation of sustainable urbotocenoses for the use of a wide range of ethnic and introduced species of plants with increased resistance to biotic and abiotic factors has been carried out. The theoretical basis of plant protection should be a preventive system based on the use of environmental protection methods with the restriction of the use of pesticides. Planning for preventive ecologically directed protection of plants from pests should begin with obtaining information about the crop and its varieties (hygrothermal regime of crop cultivation, plant resistance to harmful phytophagous species of this crop, determination of the effect of attractive or antifeeding properties of the crop on entomophages that can be used). The next stage is data on the species composition of phytophages, pests — vectors of causative agents of viral diseases of a given culture and pests that are capable of forming hemipopulations (features of the dynamics of their number, the succession series of their dominance in the process of plant growth and development). Selection of entomophages and determination of their ability to reproduce on an alternative type of food. Based on the preliminary information received, a decision is made to create a multicomponent entomocenosis in plantations before the start of plant development. In order to obtain current information, the phytosanitary state of woody plants is regularly monitored (every 20—30 days) and the dynamics of the number of components of the created useful entomocenosis, as well as a decision is made to replace or supplement its joints.
 Conclusions. In developing the concept of the formation and functioning of sustainable umbilical phytocoenoses with increased resistance to biotic and abiotic factors, it is necessary to take into account the peculiarities of damage to little ethnic and introduced species of plants with harmful organisms. Creation of sustainable urbotocenoses with increased resistance to biotic and abiotic factors has an important environmental and economic significance. The theoretical basis of protection of urbothocoenoses should be based on natural plant protection systems based on the use of environmental methods with the restriction of the use of pesticides.

Challenge of Utilization Vegetal Extracts as Natural Plant Protection Products

Natural plant protection products (known as biopesticides), derived from natural materials (plants, bacterial strains, and certain minerals) that can be used to control pests, are an alternative to plant protection chemicals (known as pesticides) due to certain advantages: less toxic to humans and the environment, no release/leaching of harmful residues, and usually much specific to the target pests. This review focuses on the systematization of information highlighting the main advantages related to the natural plant protection products used, the extractive methods of obtaining them, their physical-chemical analysis methodology, the specific constituents responsible for their pesticide effects, the mechanisms of action, and methods for direct application on vegetable crops or on seeds stored in warehouses, in order to eliminate the adverse effects occurred in the case of plant protection chemicals use. Special attention has been accorded to natural plant protection products from the spontaneous flora of Moldova (Romania’s macroeconomic region NE), which can be considered a resource of valuable secondary metabolites, especially in the form of vegetable essential oils, with biological effects and biopesticide routes of action. All presented information concludes that biopesticides can successfully replace the chemical plant protection products on small farms and especially in silos (seeds and cereals).

A New Active Substance Derived from Lyzed Willaertia magna C2c Maky Cells to Fight Grapevine Downy Mildew.

Downy mildew of grapevine is one of the most destructive grapevine diseases worldwide. Nowadays, downy mildew control relies almost exclusively on the use of chemical pesticides, including copper products, which are efficient but controversial due to their environmental toxicity. Natural plant protection products have become important solutions in the quest for the sustainable production of food and pest management. However, most biocontrol agents currently on the market, such as biofungicides or elicitors, have a limited efficacy; thus, they cannot replace chemical compounds in full. Our innovation is a natural active substance, which is a lysate of the amoeba Willaertia magna C2c Maky. This active substance is not only able to elicit grapevine defenses, but it also demonstrates direct fungicidal activity against Plasmopara viticola. The efficacy of this new natural substance was demonstrated both in a greenhouse and in a field. The amoeba lysate provided up to 77% protection to grapevine bunches in the field in a natural and safe way.

Volatile Antimicrobial Agents and In Vitro Methods for Evaluating Their Activity in the Vapour Phase: A Review.

This review summarizes data on the in vitro antimicrobial effectiveness of volatile agents of plant origin and in vitro methods for evaluating their activity in the vapour phase. As a result of literature analysis, the antimicrobial efficacy of vapours from 122 different plant species and 19 pure compounds examined in 61 studies using different in vitro tests against a broad spectrum of microorganisms was identified and summarized. In addition, 11 different techniques found in the literature are described in detail. An original classification of methods based on the solid and liquid matrix volatilization principle is proposed because carrier medium/matrix selection is crucial for the volatilization of any agents tested. This review should be useful for medicinal, pharmaceutical, food, and agricultural experts working in areas related to the management of infectious diseases (especially respiratory and skin infections), food preservation (active packaging), and protection of agriculture products (controlled atmosphere). It may also stimulate the interest of pharmaceutical, cosmetic, food, and agriculture industries in the research and development of new antimicrobial agents of natural origin. Since several original apparatuses previously developed for antimicrobial susceptibility testing in the vapour phase are described in this review, labware manufacturers may also be interested in this topic. The review also provides specific guidelines and recommendations for researchers studying the antimicrobial activity of volatile agents. The article will therefore appeal to communities of industrial stakeholders, pharmacists, physicians, food experts, agriculturists, and researchers in related areas such as pharmacology, medicinal chemistry, microbiology, natural product chemistry, food preservation and plant protection.

Chemical composition and potentiation of insecticidal and fungicidal activities of Citrus trifoliata L. fruits essential oil against Spodoptera littoralis, Fusarium oxysporum and Fusarium solani via nano-cubosomes

Development of natural nano-based plant-protection formulations represents an emerging phenomenon that has been widely improved for crops protection and for enhancing the efficiency and safety of pesticides. In the present study we isolated the essential oil from the fruits of Citrus trifoliata L. and investigated it using gas chromatography-mass spectrometry analysis. Limonene (78.46%) was the major component followed by β-Myrcene (7.94%) and Caryophyllene (4.20%). Citrus trifoliata essential oil (CTEO) loaded nano-cubosomes were successfully prepared by the emulsification technique. The insecticidal and fungicidal activities of formulated CTEO nano-cubosomes and unformulated CTEO were tested. While both of them exhibited substantial activities, CTEO nano-cubosomes were more effective than unformulated oil. It is the first time to formulate CTEO in nano-cubosomes and examine their insecticidal and fungicidal activities. In light of the current study, CTEO as it is or as nano-cubosomes is recommended as a promising candidate for pest and fungal pathogens control. Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1675063.

Oregano essential oil vapour prevents Plasmopara viticola infection in grapevine (Vitis Vinifera) and primes plant immunity mechanisms.

The reduction of synthetic fungicides in agriculture is necessary to guarantee a sustainable production that protects the environment and consumers’ health. Downy mildew caused by the oomycete Plasmopara viticola is the major pathogen in viticulture worldwide and responsible for up to 60% of pesticide treatments. Alternatives to reduce fungicides are thus utterly needed to ensure sustainable vineyard-ecosystems, consumer health and public acceptance. Essential oils (EOs) are amongst the most promising natural plant protection alternatives and have shown their antibacterial, antiviral and antifungal properties on several agricultural crops. However, the efficiency of EOs highly depends on timing, application method and the molecular interactions between the host, the pathogen and EO. Despite proven EO efficiency, the underlying processes are still not understood and remain a black box. The objectives of the present study were: a) to evaluate whether a continuous fumigation of a particular EO can control downy mildew in order to circumvent the drawbacks of direct application, b) to decipher molecular mechanisms that could be triggered in the host and the pathogen by EO application and c) to try to differentiate whether essential oils directly repress the oomycete or act as plant resistance primers. To achieve this a custom-made climatic chamber was constructed that enabled a continuous fumigation of potted vines with different EOs during long-term experiments. The grapevine (Vitis vinifera) cv Chasselas was chosen in reason of its high susceptibility to Plasmopara viticola. Grapevine cuttings were infected with P. viticola and subsequently exposed to continuous fumigation of different EOs at different concentrations, during 2 application time spans (24 hours and 10 days). Experiments were stopped when infection symptoms were clearly observed on the leaves of the control plants. Plant physiology (photosynthesis and growth rate parameters) were recorded and leaves were sampled at different time points for subsequent RNA extraction and transcriptomics analysis. Strikingly, the Oregano vulgare EO vapour treatment during 24h post-infection proved to be sufficient to reduce downy mildew development by 95%. Total RNA was extracted from leaves of 24h and 10d treatments and used for whole transcriptome shotgun sequencing (RNA-seq). Sequenced reads were then mapped onto the V. vinifera and P. viticola genomes. Less than 1% of reads could be mapped onto the P. viticola genome from treated samples, whereas up to 30% reads from the controls mapped onto the P. viticola genome, thereby confirming the visual observation of P. viticola absence in the treated plants. On average, 80% of reads could be mapped onto the V. vinifera genome for differential expression analysis, which yielded 4800 modulated genes. Transcriptomic data clearly showed that the treatment triggered the plant’s innate immune system with genes involved in salicylic, jasmonic acid and ethylene synthesis and signaling, activating Pathogenesis-Related-proteins as well as phytoalexin synthesis. These results elucidate EO-host-pathogen interactions for the first time and indicate that the antifungal efficiency of EO is mainly due to the triggering of resistance pathways inside the host plants. This is of major importance for the production and research on biopesticides, plant stimulation products and for resistance-breeding strategies.

Species-specific antimicrobial activity of essential oils and enhancement by encapsulation in mesoporous silica nanoparticles

Essential oils are volatile plant compounds that are biologically active and play an important role in natural plant protection. There are currently ∼3000 essential oils known, of which over 300 are commercially important for a variety of industries. In fact, the essential oil global market has been estimated to reach 13.94 billion USD with a demand of over 370,000 tons by 2024. These compounds have a wide variety of applications in agriculture, food and beverage, cosmetics, medicine, amongst other industries. A promising application of essential oils is as antimicrobials to target the vast number of diseases affecting crops. However, their volatile nature limits their effective use as free agents. To overcome this, we have investigated the use of mesoporous silica nanoparticles to protect essential oils from evaporation and degradation and to enhance their antimicrobial activity against bacterial phytopathogens. Silica nanoparticles were used due to their potential to be produced at an industrial scale and their biocompatibility. As a proof of concept, we evaluated 41 essential oils against bacterial phytopathogen Pseudomonas syringae pv. pisi, causative agent of pea bacterial blight. Additionally, we compared the effect of such essential oils against Pectobacterium carotovorum subsp. carotovorum and Pseudomonas fluorescens. Two of the most effective antimicrobials, cinnamon (Cinnamomum zeylanicum) and mustard (Brassica nigra) oils, were able to inhibit bacterial growth after 24 h at a concentration as low as 0.016% (v/v). Besides efficacy, the species-specificity of essential oils was demonstrated with >67% of oils tested displaying specificity towards pathogenic P. syringae pv. pisi over non-pathogenic Pseudomonas fluorescens. Furthermore, the encapsulation of essential oils into mesoporous silica nanoparticles (MSNPs) as a means of extending and improving their antimicrobial effect was found to enable a 10-fold increase in potency compared to the free essential oil. Cinnamaldehyde immobilised onto MSNPs proved to be the most effective antimicrobial, eliminating >99.8%, >99.9%, and >95% bacterial growth of P. fluorescens, P. syringae pv. pisi and P. carotovorum subsp. carotovorum, respectively. This system has the potential to be used to treat and prevent bacterial infections in crops and to enable a more controlled and effective exploitation of volatile compounds as antimicrobials.

Isolation, Colonization, and Chlorpyrifos Degradation Mediation of the Endophytic Bacterium Sphingomonas Strain HJY in Chinese Chives (Allium tuberosum).

The endophyte-plant interaction can benefit the host in many different ways. An endophytic bacterium strain (HJY) capable of degrading chlorpyrifos (CP) was isolated from Chinese chives (Allium tuberosum Rottl. ex Spreng). The isolated bacterium HJY classified as Sphingomonas sp. strain HJY could use CP as the sole carbon source. After being marked with the gfp gene, the colonization and distribution of strain HJY-gfp were directly observed in different tissues of Chinese chives with a confocal laser scanning microscope. The inoculation of strain HJY-gfp in Chinese chives resulted in a higher degradation of CP inside the plants than in uninoculated plants. With drench application, up to 70 and 66% of CP were removed from shoots and roots of inoculated Chinese chives, respectively. Moreover, up to 75% of CP was removed from the soil containing plants inoculated with HJY-gfp. With foliage application, the applied concentration of chlorpyrifos affected the degradation performance of strain HJY in Chinese chives. Significant differences were observed only between inoculated and uninoculated Chinese chives with the low applied concentration of CP. Together, other than natural endophyte-assisted plant protection for food safety, the interaction of HJY and plant may be also a promising strategy for in situ bioremediation of soil contaminated with CP.

Antifungal activity of plant essential oils and selected pseudomonas strains against Phomopsis theicola

Development of natural plant protection products as an alternative to synthetic fungicides is of significant importance regarding the environment. This study was carried out with an objective to investigate in vitro antifungal activities of several essential oils extracted from oregano, basil, myrtle and Turkish pickling herb, and the plant growth-promoting rhizobacteria in the genus Pseudomonas, against the phytopathogenic fungus Phomopsis theicola. Microdilution methods were used to determine the minimum inhibitory concentrations (MIC) of selected antimicrobial essential oils (EOs). All EOs exhibited significant levels of antifungal activity against the tested fungal isolates. The oregano EO was found the most potent one (MIC - 5.5 ?g/mL), followed by basil (MIC - 75.0?g/mL), myrtle (MIC - 775 ?g/mL) and Turkish pickling herb (MIC - 7750 ?g/mL). Inhibition of Ph. theicola mycelial growth was observed for all tested Pseudomonas spp. strains. K113 and L1 strains were highly effective and achieved more than 60% of fungal growth inhibition using the overnight culture and more than 57% inhibition by applying cell-free supernatants of both strains. A future field trial with K113 and L1 cultures and cell-free supernatants, containing extracellular metabolites toward Ph. theicola, will estimate their effectiveness and applicability as an alternative to chemical protection of apple trees.

Fluorescent Pseudomonads in the Phyllosphere of Wheat: Potential Antagonists Against Fungal Phytopathogens.

Fluorescent pseudomonads isolated from wheat leaves were characterized regarding their antagonistic potential and taxonomy in relation to protect crop plants from infestation by Fusarium and Alternaria fungi causing diseases in wheat. Using a dual culture assay, inhibition of fungal growth was found for 40 isolates of 175 fluorescent pseudomonads. Twenty-two of the antagonists were able to suppress strains of Fusarium as well as Alternaria. By means of real-time qPCR, the phlD gene encoding the antibiotic 2,4-diacetylphloroglucinol was detected in 20 isolates. On the basis of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry spectral patterns, the isolates with antagonistic activity were assigned to the phylogenetic subgroup Pseudomonas fluorescens and the closely related Pseudomonas gessardii subgroup. The results of the study suggest that pseudomonads in the phyllosphere of crop plants may possibly contribute to natural plant protection.

Factors affecting the content of the ursolic and oleanolic acid in apple peel: influence of cultivars, sun exposure, storage conditions, bruising and Penicillium expansum infection.

For health promotion and as part of natural plant protection, it might be of interest to increase the content of oleanolic acid (OA) and ursolic acid (UA) by biofortification in breeding programs, although the extent of the influence of genetic and environmental factors needs to be clarified. The objective of this study was to determine the effect of cultivar, sun exposure, storage, bruising and fungal infection on the OA and UA content in apple peel. Three apple cultivars with different ripening times--'Discovery' (early), 'Aroma' (middle) and 'Gloster' (late)--were investigated. The content of OA and UA was mainly influenced by cultivar and side subjected to sun exposure, and to a minor extent by storage and seasonal year. 'Gloster' had the highest OA and UA content of the investigated cultivars. OA and UA content on the shaded side was higher than that on the sun-exposed side in all three cultivars. Inoculation with Penicillium expansum did not have any consistent effect on OA or UA, except in a few cases where the levels decreased. OA and UA content can be increased by choice of cultivar in the breeding process and to some extent by cultural practice.