Towards eco-friendly crop protection: natural deep eutectic solvents and defensive secondary metabolites

Plant science

Host plant resistance to thrips (Thysanoptera: Thripidae) – current state of art and future research avenues

Highlights • Host plant resistance (HPR) to thrips gets increasingly important within integrated pest management.• HPR involves interdependent mechanisms ranging from plant morphology to its immune system.• Metabolomics coupled to QTL mapping enables marker assisted breeding of thrips HPR.• Modulation of inducible HPR by abiotic and biotic elicitors opens new avenues for thrips HPR.• HPR needs to integrate thrips–plant interactions, effects on natural enemies and virus transmission

Water dipping of auxin coated chrysanthemum cuttings confers protection against insect herbivores

Auxins are commonly used for commercial propagation of chrysanthemums by stem cuttings. Recent studies imply that these root-promoting hormones also affect plant defense responses. The underlying motive of this study stems from the serendipitous observation that water dipping of auxin-coated cuttings beneficially affected thrips herbivory. Therefore, the primary objective of this investigation was to explore the role of indole-3-butyric acid (IBA) in relation to herbivore susceptibility in chrysanthemum. We observed contrasting findings concerning the physical presence of IBA and it’s role in promoting susceptibility of cuttings to thrips, which may in part be explained by the phenotypical variations of cuttings generated from mother plants. Nonetheless, we repeatedly demonstrated considerable protection, in some experiments up to 37%, against thrips and leaf miner upon water dipping of IBA-coated cuttings. Assessment of polyphenol oxidase activity (PPO), 14 days after dipping treatment, suggests that neither direct induction nor priming of plant defenses are involved. Future experiments aimed at understanding the early signaling events may help to explain the underlying mechanisms involved in conferring herbivore protection. We propose a dual role for auxins in early integrated pest management strategies to maximize plant development and minimize herbivory through feasible, cost-effective water dipping treatments.</p

Cultivar Variation in Tomato Seed Coat Permeability Is an Important Determinant of Jasmonic Acid Elicited Defenses Against Western Flower Thrips

Induction of defenses is one of the most widely accepted eco-friendly approachesfor management of pests and diseases. Seeds are receptive to resistance-inducing chemicals and could offer broad-spectrum protection at the early stages of development. However, seed treatment with elicitors has previously been shown to differentially influence induced defense responses among cultivars and thus, could hamper commercial exploitation. In this context, the objective of the present study was to evaluate the genotype-dependent ability of jasmonic acid (JA) to induce resistance against western flower thrips (WFT) at the seed stage. We examined the variation in inducibility of resistance in eight commercial tomato cultivars. Causal factors accounting for discrepancies in JA-induced responses at the seed stage were phenotypically and biochemically evaluated. Seed receptivity to exogenous JA appeared to be cultivar dependent. Thrips associated silver damage was only reduced in JA seed-treated plants of cultivar Carousel. Enhancement of resistance, was not associated with activation of defense-related traits such as polyphenol oxidase activity (PPO), trichomes or volatiles.Sulfuric acid scarification, prior to JA seed incubation, significantly augmented theembryonic responsiveness to JA in cv. Moneymaker without an adverse effect ongrowth. Hence, these results support the hypothesis that seed coat permeability is a key factor for successfully inducing JA mediated thrips defenses. The outcome of our study is of translational value as it creates opportunities for the seed industry to perform pre-treatments on non-responsive cultivars as well as for tomato breeding programs to select for genetic traits that affect seed permeability

Increased morbidity of children with sickle cell disease facing bacterial contamination of water in some areas of the Province of Kenitra (Morocco)

Introduction. Sickle cell disease is the most common genetic disease in the world. It is manifested by painful crises, chronic hemolytic anemia and severe infectious episodes leading to multiple hospitalizations. Our work aimed to study repetitive childhood sickle cell crises that can potentially be linked to socioeconomic characteristics and environmental children in hospital at the University Hospital of Kenitra. Methods: This study focuses on children with sickle cell disease (N=28) hospitalized during 2021 at the University Hospital of Kenitra, as well as the bacteriological analysis of monitoring wells located in the residential areas of these patients, all from the province of Kenitra. Results: The mean age of the patients was 8.83 years; the age group under 6 represents 35.71%. The results show that 60.72% of these children come from rural areas, and the reasons for admission were dominated by infections (60.71%). Our results show that the bacteriological analysis of well water highlights the presence of some pathogens; the average concentration of total germs at 22˚C reaches 761 CFU/ml, and that of streptococci faeces is 4 CFU/ml especially in samples from rural areas (Mnasra, Sidi Taibi, Moulay Boussellham) inhabited by these children, which greatly exceeds international standards.&nbsp

Literatuuroverzicht Plantweerbaarheid : Om inzicht te verkrijgen hoe plantweerbaarheid tot stand komt en de rol van het metaboloom en microbioom daarin

Consumers, retail and governments are increasingly aware of the possible negative side effects that crop protection products can have on human and animal health and on our living environment. This results in an increasing limitation of the availability of pesticides due to European and national regulations and due to requirements set by retail and consumers. Plant resilience, the natural ability of a plant to defend itself against diseases and pests, is an important part of an integrated approach to prevent and/or control diseases and pests in a residue-free manner. In this literature review, we show the potential of activating the plant’s natural defenses based on results obtained in model crops, such as Arabidopsis and tomato, and show what has already been translated into practice. Consumers, retail and governments are increasingly aware of the possible negative side effects that crop protection products can have on human and animal health and on our living environment. This results in an increasing limitation of the availability of pesticides due to European and national regulations and due to requirements set by retail and consumers. Plant resilience, the natural ability of a plant to defend itself against diseases and pests, is an important part of an integrated approach to prevent and/or control diseases and pests in a residue-free manner. In this literature review, we show the potential of activating the plant’s natural defenses based on results obtained in model crops, such as Arabidopsis and tomato, and show what has already been translated into practice. The activation of the natural defenses is initiated by an elicitor. This is a substance that the plant recognizes and responds to by increasing plant resilience. These can be chemical substances or substances of natural origin. Two important groups are: 1. Analogues of the plant hormones jasmonic acid and salicylic acid; 2. Polysaccharides: breakdown products of chitin, pectin or cellulose. Also, some micro-organisms act as elicitors, because the plant recognizes the micro-organism itself or a substance that it secretes. The four main genera containing strains with elicitor function are: 1.Trichoderma spp.; 2.Arbuscular mycorrhizal fungi; 3 Pseudomonas spp.; 4. Bacillus spp. Examples from the literature are given of each of the mentioned elicitors and it is indicated in which commercial product they are present. Plant resilience, plant metabolites and the microbiome (the micro-organisms in and near the plant) are three factors that cannot be seen in isolation from each other. Increasing plant resistance has consequences for the composition of the plant components and the microbiome, but also vice versa: changes in the microbiome or plant components result in changes in plant resistance. Usually secondary metabolites slow down the spread of diseases and/or pests in the crop. Important groups of metabolites with regard to plant resistance are terpenoids, carotenoids, alkaloids, glucosinolates and polyphenols. Which substances within these groups are responsible for increasing plant resistance differs per crop and even per variety. Based on research to date, changes in metabolome composition in different crops appear to follow the same pattern, but more research is needed, especially in non-model crops, to understand how wide these patterns are across the plant kingdom. Microorganisms in a microbial community are in equilibrium with each other. Microorganisms with elicitor action can only settle if they become part of this equilibrium. Adding ‘good’ micro-organisms is therefore only successful under specific circumstances. Little is known about this balance and its relationship with plant resistance

Efficacious & sustainable production of Dutch ornamentals for cosmetics: a demonstration : Final report

The aim of this project is to demonstrate the potential of Dutch ornamental cultivation for the cosmetics sector by applying the principles of green extraction to three Dutch example crops (Freesia, Tulip and Iris). To generate high-quality fragrance samples, supercritical fluid extraction with CO2 is applied to carefully extract fragile, fragrant substances. Flower stems, harvested from Dutch growers were transported to the extraction company Nateco where the influence of different parameters such as temperature, pressure and application of a co-solvent, on the obtained aroma profile in two pre-selected freesia cultivars as well as one tulip cultivar was evaluated. Although there were no technical limitations, the master perfumer judged that the extracts generally encompassed a green, vegetable-like scent. Although floral and fruity notes were observed in some extracts however, these were not intense and possibly masked by more heavier, waxy components. The overall conclusion is that the fragrance intensity of the selected varieties was too low to achieve high-quality cosmetic applications. Nevertheless, the project may continue by including more intense-smelling Freesia and Tulip varieties or by including other more intense-smelling plant species. Moreover, the time of harvesting the peduncles requires some additional attention in order to get the flowers at the right stage of producing fragrances at the extraction facilities

Elicitor Application in Strawberry Results in Long-Term Increase of Plant Resilience Without Yield Loss

For a first step integrating elicitor applications into the current IPM strategy increasing plant resilience against pests, we investigated repeated elicitor treatments in a strawberry everbearer nursery and cropping cycle under glass. During nursery methyl-jasmonate (MeJA), testing induction of defenses with plant bioassays was applied every 3 weeks. Thrips damage and reproduction by spider mites, whitefly and aphids were strongly reduced upon elicitor treatment. Subsequently, we applied MeJA every 3 weeks or based on scouting pests during a whole cropping cycle. Thrips leaf bioassays and LC-MS leaf metabolomics were applied to investigate the induction of defenses. Leaf damage by thrips was lower for both MeJA application schemes compared to the control except for the last weeks. While elicitor treatments after scouting also reduced damage, its effect did not last. Thrips damage decreased from vegetative to mature plants during the cropping cycle. At the end of the nursery phase, plants in the elicitor treatment were smaller. Surprisingly, growth during production was not affected by MeJA application, as were fruit yield and quality. LC-MS leaf metabolomics showed strong induction of vegetative plants decreasing during the maturation of plants toward the end of cultivation. Concurrently, no increase in the JA-inducible marker PPO was observed when measured toward the end of cultivation. Mostly flavonoid and phenolic glycosides known as plant defense compounds were induced upon MeJA application. While induced defense decreased with the maturation of plants, constitutive defense increased as measured in the leaf metabolome of control plants. Our data propose that young, relatively small plant stages lack constitutive defense necessitating an active JA defense response. As plants, mature constitutive defense metabolites seem to accumulate, providing a higher level of basal resistance. Our results have important implications for but are not limited to strawberry cultivation. We demonstrated that repeated elicitor application could be deployed as part of an integrated approach for sustainable crop protection by vertical integration with other management tactics and horizontal integration to control multiple pests concurrently. This approach forms a promising potential for long-term crop protection in greenhouses