New live screening of plant-nematode interactions in the rhizosphere

Abstract Free living nematodes (FLN) are microscopic worms found in all soils. While many FLN species are beneficial to crops, some species cause significant damage by feeding on roots and vectoring viruses. With the planned legislative removal of traditionally used chemical treatments, identification of new ways to manage FLN populations has become a high priority. For this, more powerful screening systems are required to rapidly assess threats to crops and identify treatments efficiently. Here, we have developed new live assays for testing nematode responses to treatment by combining transparent soil microcosms, a new light sheet imaging technique termed Biospeckle Selective Plane Illumination Microscopy (BSPIM) for fast nematode detection, and Confocal Laser Scanning Microscopy for high resolution imaging. We show that BSPIM increased signal to noise ratios by up to 60 fold and allowed the automatic detection of FLN in transparent soil samples of 1.5 mL. Growing plant root systems were rapidly scanned for nematode abundance and activity, and FLN feeding behaviour and responses to chemical compounds observed in soil-like conditions. This approach could be used for direct monitoring of FLN activity either to develop new compounds that target economically damaging herbivorous nematodes or ensuring that beneficial species are not negatively impacted

High toxicity and specificity of the saponin 3-GlcA-28-AraRhaxyl-medicagenate, from Medicago truncatula seeds, for Sitophilus oryzae

<p>Abstract</p> <p>Background</p> <p>Because of the increasingly concern of consumers and public policy about problems for environment and for public health due to chemical pesticides, the search for molecules more safe is currently of great importance. Particularly, plants are able to fight the pathogens as insects, bacteria or fungi; so that plants could represent a valuable source of new molecules.</p> <p>Results</p> <p>It was observed that <it>Medicago truncatul</it>a seed flour displayed a strong toxic activity towards the adults of the rice weevil <it>Sitophilus oryzae</it> (Coleoptera), a major pest of stored cereals. The molecule responsible for toxicity was purified, by solvent extraction and HPLC, and identified as a saponin, namely 3-GlcA-28-AraRhaxyl-medicagenate. Saponins are detergents, and the CMC of this molecule was found to be 0.65 mg per mL. Neither the worm <it>Caenorhabditis elegans</it> nor the bacteria <it>E. coli</it> were found to be sensitive to this saponin, but growth of the yeast <it>Saccharomyces cerevisiae</it> was inhibited at concentrations higher than 100 μg per mL. The purified molecule is toxic for the adults of the rice weevils at concentrations down to 100 μg per g of food, but this does not apply to the others insects tested, including the coleopteran <it>Tribolium castaneum</it> and the Sf9 insect cultured cells.</p> <p>Conclusions</p> <p>This specificity for the weevil led us to investigate this saponin potential for pest control and to propose the hypothesis that this saponin has a specific mode of action, rather than acting <it>via</it> its non-specific detergent properties.</p

Valorization of Brassicaceae phytochemical diversity

Brassicaceae include many important edible and economic plants which are commonly known as the “mustard“ plant family due to the sharp flavour of their typical sulphur metabolites, the glucosinolates (GLSs). Investigation of GLSs has shown that structural types are genera/species/cultivars specific distributed and the chemical profiles are often characterized by one or two major components [1]. In some cases, compositional analysis of GLSs could be used to define the taxonomic position of less known brassica plants. As an example, the study of the GLSs profile of a poorly studied cultivar of B. oleracea, traditionally cultivated in a restricted area in South Italy and locally known as “mugnolo”, allowed to obtain relevant information which permitted to classify it as B. oleracea var. italica [2]. The present communication will describe the phytochemical diversity of some Brassicaceae and highlight its implications on bioactivity. In fact, biological diversity of plants also relies on chemical diversity mainly based on their secondary metabolites which, in addition to ecological properties, may display important pharmacological activities. Based on our chemical and biological characterization of brassica food plants, discussion will include examples of rare and less studied species/cultivars of Brassicaceae which, due to the presence of certain phytochemicals, have an added value in the promotion of a good health

Plant biodiversity: phytochemicals and health

Abstract Biodiversity may be defined as the variability occuring among living organisms and affecting all species of animals and plants, their genetics and their environment. Biological diversity of plants also relies on the chemical diversity deriving from their specialized metabolites which possess a wide range of different chemical structures as a result of plant evolution. They are responsible for the plant ecological properties and are required for the plant-environment interactions. In addition, many of them display important pharmacological properties. In the recent years, the growing interest in using plant metabolites to treat diseases in humans and animals and the high request of health products originating from natural sources rather than synthetic has revived the research on plant biodiversity to identify new bioactive molecules. Based on our studies on the chemical and biological characterization of rare or less studied plant species, the present paper aims to describe a selection of botanical species with phytopharmaceutical importance in order to highlight the chemical polymorphism deriving from their biodiversity along with its implications on bioactivity

Vitis vinifera cv Uvalino, a neglected grape vine as a source of nutraceutical lipids

Vitis vinifera cv. uvalino is an old native grape vine from Piedmont which has been recently rediscovered for the production of wine. Chemical studies have shown that the cultivar has the highest content of resveratrol (Borsa D. et al 2003) which is consistent with the high antioxidant activity displayed in in vitro experiments (Bertelli A. et al 2004). As a continuation of the chemical study on Vitis vinifera cv. uvalino we aimed to characterize the composition of the oil from its seeds. Grape seeds are considered to be a left-over product from the wine making process whose utilization is however of economic relevance for waste reduction. Grape seed oil, “olio di vinaccioli”, is a high-quality edible oil with beneficial health properties mainly due to its content of unsaturated fatty acids. In our study, chemical profiling of the seed oil from V. vinifera cv uvalino has been obtained by a combination of spectrometric and spectroscopic techniques such as GC, GC-MS, NMR and ESI-MS/MS. Uvalino’s grape seed oil was found to consist of triacylglycerols (TAG) as in the case of seed oils from other grape cultivars (Bail S. et al 2008). Analysis of TAG fatty acid composition indicated that the two unsaturated linoleic acid (72.87 %) and oleic acid (13.20%) are dominant, whereas palmitic acid (9.59%) is the most abundant saturated fatty acid. Moreover, ESI-MS/MS allowed to disclose the most abundant TAG species which include components at m/z 901 (OLO), 898 (LLL) and 877 (LSP). In addition to the above, an analytical method based on HPLC-ELSD detection has been developed for identification of TAG species in grape seed oils and it will be presented here

Plant metabolites for management of plant parasitic nematodes

lant-parasitic nematodes are among the best known crop pests responsible for substantial value loss of crops of agronomic importance. Management of these pests has been mainly achieved with chemical nematicides throughout the past decades. Overuse of synthetic pesticides has generated a series of environmental problems and human and animal health concerns leading to their progressive withdrawal from the European market as well as to consider the use of alternative control strategies. In the recent years the interest in the application of botanical nematicides has increased tremendously, leading to the discover of new plant sources, plant extracts and phytochemicals with potential as nematicidals. Groups of plant secondary metabolites most promising in the development of pesticidal formulations are glucosinolates,saponins and terpenoid phytoconstituents. In the present communication we will describe our latest results on the nematicidal effects of selected plant extracts rich in the above mentioned compounds as well as the biocidal activity of pure plant metabolites against highly destructive phytoparasites such as the root-knot nematode Meloidogyne incognita or the ectoparasite dagger nematode Xiphinema index

Glucosinolate profile of Eruca sativa, Diplotaxis tenuifolia and Diplotaxis erucoides grown in soil and soilless systems

A B S T R A C T Soilless cultivation systems (SCS) are increasingly used to produce high quality baby-leaf arugula, appreciated by consumers for its pungent taste, due to the content of glucosinolates (GLS). Given all of the health benefits attributed to GLSs, there is great interest in understanding whether and how soilless growing systems may affect the GLS profile of arugula. For this purpose, a study was conducted to compare the GLS profile of Diplotaxis erucoides, D. tenuifolia, and Eruca sativa grown side-by-side under protected environment in a conventional soilsystem (CSS) and in a SCS. Genotype and growing-system resulted in a significant effect on GLS content, while the resulting qualitative GLS profile was species-specific. Despite the growing-system, six different GLSs were identified from plants of D. tenuifolia and E. sativa, while only sinigrin was detected in plants of D. erucoides. Total GLS content was on average 9.85, 8.23, and 7.96 mg g−1 of dry weight in D. erucoides, D. tenuifolia, and E. sativa, grown in CSS, respectively. The same three species grown in SCS synthesized 36%, 51%, and 41% more GLSs than plants grown in CSS, respectively. Soilless cultivation may be adopted to increase the GLS content and enhance the nutritional quality of brassicas leafy vegetables. 1. Introduction Brassicaceae are among the oldest cultivated crops (Schmidt and Bancroft, 2011) with a production across Europe estimated at approximately 70 million tons/annum, and are considered a rich source of health-promoting phytochemicals (Avato and Argentieri, 2015). They are commonly referred to as the “mustard” (from the Latin mustum ardens) plant family, due to the sharp, potent flavour attributable to their main sulphur metabolites, the glucosinolates (GLSs) (Björkman et al., 2011; Petropoulos et al., 2017). When plant tissues are crushed or powdered, they are hydrolysed releasing the typical hot, pungent mustard components that are associated with the botanical family. While Brassicaceae contain several phytonutrients, GLSs are their most commonly studied constituents (Argentieri et al., 2012; Argentieri et al., 2011; Björkman et al., 2011; D’Antuono et al., 2008). Although anti-nutritional effects, resulting in goitre and liver damage in animals have been reported for GLSs (Cartea and Velasco, 2008; Tripathi and Mishra, 2007), several epidemiological studies have shown that in humans, high consumption of Brassica vegetables is inversely linked to cancer risk (Fimognari and Hrelia, 2007; Petropoulos et al., 2017). Moreover, it has been shown that GLSs and their breakdown product