Combined bacterial and mycorrhizal inocula improve tomato quality at reduced fertilization

Plant Growth Promoting Bacteria (PGPB) and Arbuscular Mycorrhizal Fungi (AMF) can positively affect plant nutrition and growth. Recent studies have also shown that rhizospheric microorganisms can result in improved fruit features. Aim of this work was to evaluate, in an industrial farming, the effects of three selected biostimulants (consisting of a mix of Plant Growth Promoting Bacteria and Arbuscular Mycorrhizal Fungi), employed in conditions of reduced fertilization on yield, fruit quality and nutritional value. Tomato plants were inoculated with AM fungi and Pseudomonas sp. 19Fv1T or P. fluorescens C7, transplanted and grown in open field under conditions of reduced fertilization. The impact of the microorganisms on the fruit yield and nutritional value was assessed by measuring the production, fruit size and concentration of soluble sugars, organic acids, carotenoids and ascorbate. The size and biomass of tomato fruits were affected by the inocula. Sugar concentration was increased by the selected microorganisms. All the mixtures induced an enhancement of malic acid, while double colonization with AMF and PGPB increased \u3b2-carotene concentration in fruits if compared to controls. The results of the present study show that inoculation with soil microorganisms can help to drastically reduce the use of chemical fertilization, maintaining and, in some cases, even improving the tomato fruit yield and quality. This can lead to economical, environmental and human health benefits in relation to the increased sustainability

Arbuscular mycorrhizal symbiosis affects the grain proteome of Zea mays: a field study

Maize is one of the most important crops worldwide and is strongly dependent on arbuscular mycorrhiza (AM) fungi, organisms that form a mutualistic association with land plants. In maize, AM symbiosis enhances spike dry weight, spike length, spike circumference, and the dry weight and dimensions of the grain. Notwithstanding its ubiquitous nature, the detailed relationship between AM fungal colonization and plant development is not completely understood. To facilitate a better understanding of the effects of AM fungi on plants, the work reported here assessed the effects of a consortium of AM fungi on the kernel proteome of maize, cultivated in open-field conditions. To our knowledge, this is the first report of the modulation of a plant seed proteome following AM fungal inoculation in the field. Here, it was found that AM fungi modify the maize seed proteome by up-regulating enzymes involved in energetic metabolism, embryo development, nucleotide metabolism, seed storage and stress responses

Does mycorrhization influence herbivore-induced volatile emission in Medicago truncatula?

Symbiosis with mycorrhizal fungi substantially impacts secondary metabolism and defensive traits of colonised plants. In the present study, we investigated the influence of mycorrhization (Glomus intraradices) on inducible indirect defences against herbivores using the model legume Medicago truncatula. Volatile emission by mycorrhizal and non-mycorrhizal plants was measured in reaction to damage inflicted by Spodoptera spp. and compared to the basal levels of volatile emission by plants of two different cultivars. Emitted volatiles were recorded using closed-loop stripping and gas chromatography/mass spectrometry. The documented volatile patterns were evaluated using multidimensional scaling to visualise patterns and stepwise linear discriminant analysis to distinguish volatile blends of plants with distinct physiological status and genetic background. Volatile blends emitted by different cultivars of M. truncatula prove to be clearly distinct, whereas mycorrhization only slightly influenced herbivore-induced volatile emissions. Still, the observed differences were sufficient to create classification rules to distinguish mycorrhizal and non-mycorrhizal plants by the volatiles emitted. Moreover, the effect of mycorrhization turned out to be opposed in the two cultivars examined. Root symbionts thus seem to alter indirect inducible defences of M. truncatula against insect herbivores. The impact of this effect strongly depends on the genetic background of the plant and, hence, in part explains the highly contradictory results on tripartite interactions gathered to date

Hypericin and pseudohypericin concentrations of a valuable medicinal plant Hypericum perforatum L. are enhanced by arbuscular mycorrhizal fungi

Hypericum perforatum L. (St. John’s-wort, Hypericaceae) is a valuable medicinal plant species cultivated for pharmaceutical purposes. Although the chemical composition and pharmacological activities of H. perforatum have been well studied, no data are available concerning the influence of arbuscular mycorrhizal fungi (AMF) on this important herb. A laboratory experiment was therefore conducted in order to test three AMF inocula on H. perforatum with a view to show whether AMF could influence plant vitality (biomass and photosynthetic activity) and the production of the most valuable secondary metabolites, namely anthraquinone derivatives (hypericin and pseudohypericin) as well as the prenylated phloroglucinol—hyperforin. The following treatments were prepared: (1) control—sterile soil without AMF inoculation, (2) Rhizophagus intraradices (syn. Glomus intraradices), (3) Funneliformis mosseae (syn. Glomus mosseae), and (4) an AMF Mix which contained: Funneliformis constrictum (syn. Glomus constrictum), Funneliformis geosporum (syn. Glomus geosporum), F. mosseae, and R. intraradices. The application of R. intraradices inoculum resulted in the highest mycorrhizal colonization, whereas the lowest values of mycorrhizal parameters were detected in the AMF Mix. There were no statistically significant differences in H. perforatum shoot mass in any of the treatments. However, we found AMF species specificity in the stimulation of H. perforatum photosynthetic activity and the production of secondary metabolites. Inoculation with the AMF Mix resulted in higher photosynthetic performance index (PItotal) values in comparison to all the other treatments. The plants inoculated with R. intraradices and the AMF Mix were characterized by a higher concentration of hypericin and pseudohypericin in the shoots. However, no differences in the content of these metabolites were detected after the application of F. mosseae. In the case of hyperforin, no significant differences were found between the control plants and those inoculated with any of the AMF applied. The enhanced content of anthraquinone derivatives and, at the same time, better plant vitality suggest that the improved production of these metabolites was a result of the positive effect of the applied AMF strains on H. perforatum. This could be due to improved mineral nutrition or to AMF-induced changes in the phytohormonal balance. Our results are promising from the biotechnological point of view, i.e. the future inoculation of H. perforatum with AMF in order to improve the quality of medicinal plant raw material obtained from cultivation

Formación socioemocional desde los sectores de aprendizaje : aprendizajes vitales

En este cuadernillo algunos profesionales, especialistas de cada Sector de Aprendizaje, exponen competencias vitales para el desarrollo y la vida humana propias de su especialidad. El aprendizaje de objetivos relativos a competencias propias de cada Sector de Aprendizaje, puede salvar vidas y cambiar historias de vida. Las competencias que aborda el texto en cada subsector están prescritas en los objetivos del currículo chileno, conforme a lo que llamamos tridimensionalidad curricular (contenidos, habilidades y actitudes). No siempre les otorgamos el valor que tienen para el desarrollo y la seguridad personal, y tampoco estamos suficientemente conscientes de las implicancias. Tampoco las implicancias fatales que tiene el no aprenderlas

The Effects of Arbuscular Mycorrhizal Fungi on Direct and Indirect Defense Metabolites of Plantago lanceolata L.

Arbuscular mycorrhizal fungi can strongly influence the metabolism of their host plant, but their effect on plant defense mechanisms has not yet been thoroughly investigated. We studied how the principal direct defenses (iridoid glycosides) and indirect defenses (volatile organic compounds) of Plantago lanceolata L. are affected by insect herbivory and mechanical wounding. Volatile compounds were collected and quantified from mycorrhizal and non-mycorrhizal P. lanceolata plants that underwent three different treatments: 1) insect herbivory, 2) mechanical wounding, or 3) no damage. The iridoids aucubin and catalpol were extracted and quantified from the same plants. Emission of terpenoid volatiles was significantly higher after insect herbivory than after the other treatments. However, herbivore-damaged mycorrhizal plants emitted lower amounts of sesquiterpenes, but not monoterpenes, than herbivore-damaged non-mycorrhizal plants. In contrast, mycorrhizal infection increased the emission of the green leaf volatile (Z)-3-hexenyl acetate in untreated control plants, making it comparable to emission from mechanically wounded or herbivore-damaged plants whether or not they had mycorrhizal associates. Neither mycorrhization nor treatment had any influence on the levels of iridoid glycosides. Thus, mycorrhizal infection did not have any effect on the levels of direct defense compounds measured in P. lanceolata. However, the large decline in herbivore-induced sesquiterpene emission may have important implications for the indirect defense potential of this species

Biologically regulated nutrient supply systems: compost and arbuscular mycorrhizas - a review

To achieve global food security, we will need to produce more food, and do so in an environmentally sustainable manner. Inorganic fertilizers have been instrumental in increasing food production, but with some fertilizers becoming increasingly scarce and expensive, we also need to consider other options for providing agricultural plants with nutrients. To this end, there has been increased interest in the potential to make better use of the nutrients tied up in organic matter; composts are an example of this, and are the focus of this review. Plant nutrient acquisition can be enhanced through the formation of arbuscular mycorrhizas (AM). The purpose of this review is to explore interactions between compost and AM, with an emphasis on the impacts of compost addition and formation and functioning of AM. Based on available literature, it is clear that the application of compost either has a positive or neutral effect on the formation of the symbiosis, and that dual application of compost and arbuscular mycorrhizal fungi (AMF) provides clear benefits to plants in terms of growth and nutrition. There is also emerging evidence that dual application also provides benefits in terms of soil structure. Taken together, the conclusion of this review is that the biologically regulated nutrient supply systems based on compost and AM are compatible.Timothy R. Cavagnar