Mycorrhiza induced resistance against pests: from the lab to the field

1 página - Conferencia invitada presentada en Iberian Plant Biology 2023. XVIII Portuguese-Spanish Congress on Plant Biology and the XXV Meeting of the Spanish Society of Plant Biology. 9-12 Julio 2023, Braga, PortugalArbuscular mycorrhizal fungi (AMF) can prime plant defences increasing their resistance against pathogens and insect herbivores. Using tomato as a model, we have shown that inoculation with different AMF reduces the performance of the chewing herbivore Spodoptera exigua and the leaf miner Tuta absoluta. Transcriptomic and metabolomics analyses revealed that this Mycorrhiza Induced Resistance (MIR) is associated to boosted activation of plant direct and indirect defences in response to the attackers. We found primed accumulation in attacked leaves of antiherbivore metabolites, including alkaloids and polyamine conjugates, and functional analyses demonstrated that some of the identified compounds significantly inhibit herbivore development. In addition, the symbiosis altered the volatile blends released by the plant, and enhanced the attraction of natural enemies of the pests (Nesidiocoris tenuis, commonly used in biocontrol programs). Finally, networks analyses allowed the identification of key regulators of the primed response within the jasmonic acid and ethylene signalling pathways. Despite the many studies showing induced resistance by microorganisms in different plant‐pest systems, the variability in the protection achieved under agronomic settings is hindering the application of this strategy in agriculture. Plant‐microbe‐herbivore interactions are highly context dependent, with multiple biotic and abiotic factors influencing the final output. Identifying such factors is essential to optimize the application of microbial inoculants for crop protection in agriculture. We found that the plant genotype and nutrient availability are important drivers of the context dependency of MIR in tomato. Despite of the variability, comparisons across different experimental scales, from controlled lab set‐ups to commercial production conditions, confirmed that MIR can be achieved under crop production conditions and is compatible with other biocontrol methods. Accordingly, MIR can be a relevant addition to current Integrated Pest Management Programs

The local skin celular immune response determines the clinical outcome of sarcoptic mange in Iberian ibex (Capra pirenaica)

13 páginas, 8 figuras, 7 tablas.This project was funded by the Consejería de Medio Ambiente de la Junta de Andalucía (project 173/2009/M/00;03/15/M/00; 861_11_M_00 and 2016/00014/M) and the Spanish Ministerio de Economía y Competitividad (projects CGL2012-40043-C02-01, CGL2012-40043-C02-02, and CGL2016-80543-P). The authors’ research activities are partially supported by the Plan Andaluz de Investigación (RNM-118 group). MV is supported by a FI-GENCAT Fellowship (2020_FI_B2_00049, which is cofinanced by the Agència de Gestió d’Ajuts Universitaris i de Recerca and the European Social Fund). GM is a Serra Húnter Fellow.Peer reviewe

Ivermectin plasma concentration in iberian ibex (capra pyrenaica) following oral administration: a pilot study

7 páginas, 1 tabla, 1 figura.Sarcoptic mange is considered the main driver of demographic declines occurred in the last decades in Iberian ibex (Capra pyrenaica) populations. Mass treatment campaigns by administration of in-feed acaricides are used as a measure to mitigate the impact of mange in the affected populations. However, there are no data on ivermectin (IVM) pharmacokinetics in this wild caprine, and the treatment through medicated feed is not endorsed by evidence on its effectiveness. The aim of this study is to determine the pharmacokinetic profile of IVM in plasma samples of ibexes after the experimental oral administration of IVM, using high performance liquid chromatography (HPLC) with automated solid phase extraction and fluorescence detection. A dose of 500 µg of IVM per body weight was orally administered in a feed bolus to nine healthy adult ibexes (seven males and two females). Blood samples were collected by jugular venipuncture into heparin-coated tubes at day 1, 2, 3, 4, 7, 10, 15, and 45 post-administration (dpa). The highest plasma concentration of IVM (Cmax = 3.4 ng/ml) was detected 24 h after the oral administration (T1), followed by a rapid decrease during the first week post-administration. Our results reveal that plasma IVM concentration drops drastically within 5 days of ingestion, questioning the effectiveness of a single in-feed dose of this drug to control sarcoptic mange. To the best of our knowledge, this is the first study on plasma availability of oral IVM in ibexes and in any wild ungulate species.This project was funded by the Consejería de Medio Ambiente de la Junta de Andalucía (project 173/2009/M/00; 03/15/M/00; 861_11_M_00 and 2016/00014/M), and by the Spanish Ministerio de Economía y Competitividad (projects CGL2012-40043-C02-01, CGL2012-40043-C02- 02, and CGL2016-80543-P). The authors’ research activities are partially supported by the Plan Andaluz de Investigación (RNM 118 group). MV is supported by a FI-GENCAT Fellowship (2020_FI_B2_00049, co-financiated by Agència de Gestió d’Ajuts Universitaris i de Recerca and European Social Fund) and ES by the Spanish Ministerio de Ciencia Innovación y Universidades (MICINN) through a Ramon y Cajal agreement (RYC-2016-21120). GM is a Serra Húnter Fellow.Peer reviewe

How do nitrogen and phosphorus deficiencies affect strigolactone production and exudation?

Plants exude strigolactones (SLs) to attract symbiotic arbuscular mycorrhizal fungi in the rhizosphere. Previous studies have demonstrated that phosphorus (P) deficiency, but not nitrogen (N) deficiency, significantly promotes SL exudation in red clover, while in sorghum not only P deficiency but also N deficiency enhances SL exudation. There are differences between plant species in SL exudation under P- and N-deficient conditions, which may possibly be related to differences between legumes and non-legumes. To investigate this possibility in detail, the effects of N and P deficiencies on SL exudation were examined in Fabaceae (alfalfa and Chinese milk vetch), Asteraceae (marigold and lettuce), Solanaceae (tomato), and Poaceae (wheat) plants. In alfalfa as expected, and unexpectedly in tomato, only P deficiency promoted SL exudation. In contrast, in Chinese milk vetch, a leguminous plant, and in the other non-leguminous plants examined, N deficiency as well as P deficiency enhanced SL exudation. Distinct reductions in shoot P levels were observed in plants grown under N deficiency, except for tomato, in which shoot P level was increased by N starvation, suggesting that the P status of the shoot regulates SL exudation. There seems to be a correlation between shoot P levels and SL exudation across the species/families investigated

Diseases of Iberian ibex (Capra pyrenaica)

36 páginas, 7 figuras, 4 tablas.Iberian ibex (Caprapyrenaica) is an ecologically and economically relevant medium-sized emblematic mountain ungulate. Diseases participate in the population dynamics of the species as a regulating agent, but can also threaten the conservation and viability of vulnerable population units. Moreover, Iberian ibex can also be a carrier or even a reservoir of pathogens shared with domestic animals and/or humans, being therefore a concern for livestock and public health. The objective of this review is to compile the currently available knowledge on (1) diseases of Iberian ibex, presented according to their relevance on the health and demography of free-ranging populations; (2) diseases subjected to heath surveillance plans; (3) other dis-eases reported in the species; and (4) diseases with particular relevance in captive Iberian ibex populations. The systematic review of all the information on diseases affecting the species unveils unpublished reports, scientific communications in meetings, and scientific articles, allowing the first comprehensive compilation of Iberian ibex diseases. This review identi-fies the gaps in knowledge regarding pathogenesis, immune response, diagnostic methods, treatment, and management of diseases in Iberian ibex, providing a base for future research. Moreover, this challenges wildlife and livestock disease and wildlife population managers to assess the priorities and policies currently implemented in Iberian ibex health surveillance and monitoring and disease management.Open Access Funding provided by Universitat Autonoma de Barcelona. Part of the authors benefitted of the support of the Consejería de Medio Ambiente of the Junta de Andalucía (Spain) to the group RNN 118 through the grants 173/2009/M/00; 03/15/M/00; 861_11_M_00, 2016/00014/M. This review benefitted from funding of the Spanish Ministerio de Economía y Competitividad through the grants CGL2012-40043-C02-01, CGL2012-40043-C02-02, and CGL2016-80543-P. Marta Valldeperes was supported by the pre-doctoral grant 2020_FI_B2_00049, funded by the Agència de Gestió d'Ajuts Universitaris i de Recerca of the Generalitat de Catalunya (Spain) and the European Social Fund.Peer reviewe

Hormonal and transcriptional profiles highlight common and differential host responses to arbuscular mycorrhizal fungi and the regulation of the oxylipin pathway

Arbuscular mycorrhizal (AM) symbioses are mutualistic associations between soil fungi and most vascular plants. The symbiosis significantly affects the host physiology in terms of nutrition and stress resistance. Despite the lack of host range specificity of the interaction, functional diversity between AM fungal species exists. The interaction is finely regulated according to plant and fungal characters, and plant hormones are believed to orchestrate the modifications in the host plant. Using tomato as a model, an integrative analysis of the host response to different mycorrhizal fungi was performed combining multiple hormone determination and transcriptional profiling. Analysis of ethylene-, abscisic acid-, salicylic acid-, and jasmonate-related compounds evidenced common and divergent responses of tomato roots to Glomus mosseae and Glomus intraradices, two fungi differing in their colonization abilities and impact on the host. Both hormonal and transcriptional analyses revealed, among others, regulation of the oxylipin pathway during the AM symbiosis and point to a key regulatory role for jasmonates. In addition, the results suggest that specific responses to particular fungi underlie the differential impact of individual AM fungi on plant physiology, and particularly on its ability to cope with biotic stresses