Confronting stresses affecting olive cultivation from the holobiont perspective

The holobiont concept has revolutionized our understanding of plant-associated microbiomes and their significance for the development, fitness, growth and resilience of their host plants. The olive tree holds an iconic status within the Mediterranean Basin. Innovative changes introduced in olive cropping systems, driven by the increasing demand of its derived products, are not only modifying the traditional landscape of this relevant commodity but may also imply that either traditional or emerging stresses can affect it in ways yet to be thoroughly investigated. Incomplete information is currently available about the impact of abiotic and biotic pressures on the olive holobiont, what includes the specific features of its associated microbiome in relation to the host’s structural, chemical, genetic and physiological traits. This comprehensive review consolidates the existing knowledge about stress factors affecting olive cultivation and compiles the information available of the microbiota associated with different olive tissues and organs. We aim to offer, based on the existing evidence, an insightful perspective of diverse stressing factors that may disturb the structure, composition and network interactions of the olive-associated microbial communities, underscoring the importance to adopt a more holistic methodology. The identification of knowledge gaps emphasizes the need for multilevel research approaches and to consider the holobiont conceptual framework in future investigations. By doing so, more powerful tools to promote olive’s health, productivity and resilience can be envisaged. These tools may assist in the designing of more sustainable agronomic practices and novel breeding strategies to effectively face evolving environmental challenges and the growing demand of high quality food products

The roots of olive cultivars differing in tolerance to Verticillium dahliae show quantitative differences in phenolic and triterpenic profiles

This work was supported by the grants PID2019-106283RB-I00, BES-2017-081269 and FPU19/00700 of the Spanish Ministerio de Ciencia, Innovacion y Universidades (MICIU)/Agencia Estatal de Investigacion (AEI), and the grant RYC2021-032996-I funded by MCIN/AEI/10.13039/501100011033 and by "European Union NextGenerationEU/PRTR". This research was partially funded by FEDER/Junta de Andalucia-Consejeria de Conocimiento, Investigacion y Universidad, Junta de Andalucia Transformacion Economica, Industria, Conocimiento y Universidades, Proyecto P20_00263; and FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento, Proyecto B-AGR-416-UGR18.Verticillium wilt of olive (VWO), caused by Verticillium dahliae, is a major concern in many olive- growing countries. An efficient VWO control measure is the use of tolerant/resistant cultivars. Low information is available about olive secondary metabolites and its relationship with VWO tolerance. In this study, a comprehensive metabolic profiling of the roots of six olive cultivars differing in their level of tolerance/susceptibility to VWO was addressed. Potential changes in the metabolite profiles due to the presence of the pathogen were also assessed. A strong relationship between the quantitative basal composition of the root secondary metabolic profile and VWO tolerance/susceptibility of olive varieties was found. Tolerant cultivars showed higher content of secoiridoids, while the susceptible ones presented greater amounts of verbascoside and methoxypinoresinol glucoside. The presence of V. dahliae only caused few significant variations mostly restricted to the earliest times after inoculation. Thus, a rapid activation of biochemical- based root defense mechanisms was observed.Spanish Ministerio de Ciencia, Innovacion y Universidades (MICIU)/Agencia Estatal de Investigacion (AEI) PID2019-106283RB-I00, BES-2017-081269, FPU19/00700MCIN/AEI RYC2021-032996-IEuropean Union NextGenerationEU/PRTR RYC2021-032996-IFEDER/Junta de Andalucia-Consejeria de Conocimiento, Investigacion y UniversidadJunta de Andalucia Transformacion Economica, Industria, Conocimiento y Universidades P20_00263FEDER/Junta de Andalucia-Consejeria de Economia y Conocimiento B-AGR-416-UGR1

Verticillium wilt of olive in the Guadalquivir Valley (southern Spain): relations with some agronomical factors and spread of Verticillium dahliae

Verticillium wilt of olive (VWO) is now the most destructive olive disease in the Guadalquivir valley in Andalucía (southern Spain). Disease surveys, conducted to assess the association of agronomical and geographical factors with the current spread of the disease, have shown that VWO is widespread in the valley, with a mean disease incidence (DI) in infested plots reaching 20.4%  (9000 inspected trees), but with significant differences among the provinces surveyed (25.7, 23.7 and 12%, for Jaén, Córdoba and Seville, respectively). The DI was significantly higher in irrigated (20.7%) than in dry-farming (18.3%) orchards, and also higher in non-tilled orchards (25.6%) than in regularly-tilled orchards (16.3%). The DI was likewise significantly lower for tree densities above 200 trees ha-1; and it was higher (21.5%) when the orchards were located near areas where other V. dahliae host plants were cultivated, than if the orchards were surrounded by non-host plants (11.9%). Lastly, the DI was significantly higher in plots where the tree were less than 25 year old and in plantations close to the Guadalquivir River (less than 10 km). ‘Picual’ was the cultivar most often affected with the disease, reaching a DI of 41.9% in orchards where this cultivar was grown. Highly virulent defoliating (D) isolates in the plantation surveyed were significantly more common (67.7%) than non-defoliating (ND) isolates (32.3%). These factors could explain the substantial increase in incidence and severity of VWO seen in the valley during the last decade

Early and delayed long-term transcriptional changes and short-term transient responses during cold acclimation in olive leaves

Low temperature severely affects plant growth and development. To overcome this constraint, several plant species from regions having a cool season have evolved an adaptive response, called cold acclimation. We have studied this response in olive tree (Olea europaea L.) cv. Picual. Biochemical stress markers and cold-stress symptoms were detected after the first 24 h as sagging leaves. After 5 days, the plants were found to have completely recovered. Control and cold-stressed plants were sequenced by Illumina HiSeq 1000 paired-end technique. We also assembled a new olive transcriptome comprising 157,799 unigenes and found 6,309 unigenes differentially expressed in response to cold. Three types of response that led to cold acclimation were found: short-term transient response, early long-term response, and late long-term response. These subsets of unigenes were related to different biological processes. Early responses involved many cold-stress-responsive genes coding for, among many other things, C-repeat binding factor transcription factors, fatty acid desaturases, wax synthesis, and oligosaccharide metabolism. After long-term exposure to cold, a large proportion of gene down-regulation was found, including photosynthesis and plant growth genes. Up-regulated genes after long-term cold exposure were related to organelle fusion, nucleus organization, and DNA integration, including retrotransposons.This work was supported by grant AGR-5948 from Junta de Andalucía (Consejería de Economía, Innovación y Ciencia) and Ministerio de Ciencia e Innovación. Funding to pay the Open Access publication charges for this article was provided by the University of Jaén.Peer reviewe

Cold response in olive tree; A RNAseq study

Póster presentado en el COST TD801 StatSeq 5th Workshop, celebrado en Helsinki del 24 al 26 de abril de 2013.Low temperature severely affects plant growth and development. Several plant species have evolved an adaptive response, named cold acclimation. In order to study this response in olive tree (Olea europaea), we maintained twomonths- old vegetative propagated olive trees cv. Picual at low temperature (14h at 10ºC with light, 10h at 4ºC at the dark) for 15 days. Control plants were maintained in field growing conditions. Cold stress symptoms were observed after the first 24h as sagging leaf and biochemical stress markers. After 5 days the plants were observed completely recovered. We extracted RNA from leaves of three control plants and the same number from 24h and 10 days cold stressed plants. We pooled RNA and made two cDNA libraries for sequencing. We used Illumina HiSeq 1000 sequencer.Peer Reviewe

Assessment of oceanographic services for the monitoring of highly anthropised coastal lagoons: The Mar Menor case study

Ocean monitoring systems are designed for continuous monitoring to track their evolution and anticipate environmental issues. However, they are often based on IoT systems that offer little spatial coverage and are hard to maintain. Satellite remote sensing offers good geographical coverage but they also face several challenges to become a monitoring system. This paper introduces an easy-to-use software tool to crawl water-quality data from up to 6 satellite instruments from the ESA and NASA. Particularly, Chl-a data is deeply analyzed in terms of reliability and data coverage for a highly anthropised coastal lagoon (Mar Menor, Spain), where serious socio-environmental issues are happening. Our results show a good linear correlation between in situ data and SRS data, reaching values close to 0.9, and stating the relevance of organic matter inputs from ephemeral streams in Chl-a concentrations. Moreover, temporal granularity is increased from 5 to 1.5 days by combining SRS sources.Preprin

Efecto de una cepa de Fusarium oxysporum y de diversas levaduras sobre la nutrición férrica de plantas de pepino y tomate

Trabajo presentado en el XVI Congreso Nacional de Ciencias Hortícolas, celebrado en Córdoba del 17 al 22 de octubre de 2021,El hierro (Fe) es un micronutriente esencial para las plantas. En suelos calizos se encuentra en su forma oxidada (Fe 3+), presentando baja solubilidad y disponibilidad para las plantas. Bajo deficiencia de Fe, las plantas dicotiledóneas inducen diversas respuestas fisiológicas y morfológicas en sus raíces para facilitar así su captación y paliar los efectos que produce su deficiencia. Existen evidencias de que determinados microorganismos rizosféricos, como los que provocan la Respuesta Sistémica Inducida (ISR), pueden facilitar la nutrición férrica de las plantas. El objetivo de este trabajo ha sido, por una parte, estudiar el efecto de la cepa no patogénica de Fusarium oxysporum (FO12), posiblemente inductora de ISR, sobre el crecimiento y clorosis de plantas de tomate (Solanum lycopersicum Mill.), y sobre la colonización de raíces de pepino (Cucumis sativus L.). Por otra parte, estudiar el efecto de determinadas levaduras (Debaryomyces hansenii, Saccharomyces cerevisiae y Hansenula polymorpha) sobre diversas respuestas a la deficiencia de Fe en plantas de pepino. Los experimentos con tomate se han desarrollado en suelo calizo y los de pepino en cultivo hidropónico. Los resultados obtenidos con FO12 han mostrado su capacidad para colonizar endofiticamente las raíces de pepino y su efecto promotor del crecimiento, la concentración de clorofila y de Fe (en hojas) en plantas de tomate. Las diferentes levaduras utilizadas han causado inducción de la capacidad reductora de Fe 3+, de la acidificación de la rizosfera, y de la proliferación de pelos radicales en la zona subapical de las raíces de pepino. Estos resultados sugieren que, tanto FO12 como las diferentes levaduras utilizadas, tienen potencial como biofertilizantes de Fe.Plan Propio de la Universidad de Córdoba y Ministerio de Ciencia e Innovación

Cepa de trichoderma útil para el tratamiento y/o prevención de infecciones provocadas por microorganismos fitopatógenos

Cepa de trichoderma útil para el tratamiento y/o prevención de infecciones provocadas por microorganismos fitopatógenos. La invención se refiere a una nueva cepa de hongos perteneciente a la especie Trichoderma harzianum resistente a cobre capaz de inhibir el crecimiento de otros microorganismos, preferiblemente hongos, fitopatógenos. Por ello, se propone su uso como fertilizante y para la prevención y/o tratamiento de infecciones de plantas y/o suelos provocadas por microorganismos fitopatógenos, preferiblemente por los patotipos defoliante o no defoliante de Verticillium dahliae, agente causante de la verticilosis del olivo. Además, debido a su capacidad de resistencia a cobre, la cepa de la invención puede ser utilizada en un método de prevención y/o tratamiento de infecciones provocadas por microorganismos, preferiblemente hongos, fitopatógenos en combinación con otros agentes antifúngicos.Españ

Innate IRE1α-XBP1 activation by viral single-stranded RNA and its influence on lung cytokine production during SARS-CoV-2 pneumonia

The utilization of host-cell machinery during SARS-CoV-2 infection can overwhelm the protein-folding capacity of the endoplasmic reticulum and activate the unfolded protein response (UPR). The IRE1α-XBP1 arm of the UPR could also be activated by viral RNA via Toll-like receptors. Based on these premises, a study to gain insight into the pathogenesis of COVID-19 disease was conducted using nasopharyngeal exudates and bronchioloalveolar aspirates. The presence of the mRNA of spliced XBP1 and a high expression of cytokine mRNAs were observed during active infection. TLR8 mRNA showed an overwhelming expression in comparison with TLR7 mRNA in bronchioloalveolar aspirates of COVID-19 patients, thus suggesting the presence of monocytes and monocyte-derived dendritic cells (MDDCs). In vitro experiments in MDDCs activated with ssRNA40, a synthetic mimic of SARS-CoV-2 RNA, showed induction of XBP1 splicing and the expression of proinflammatory cytokines. These responses were blunted by the IRE1α inhibitor MKC8866, the TLR8 antagonist CU-CPT9a, and knockdown of TLR8 receptor. In contrast, the IRE1α-XBP1 activator IXA4 enhanced these responses. Based on these findings, the TLR8/IRE1α system seems to play a significant role in the induction of the proinflammatory cytokines associated with severe COVID-19 disease and might be a druggable target to control cytokine storm.This work was supported by Junta de Castilla y León/Fondo Social Europeo. Valladolid Section of Asociación Española contra el Cáncer. Fondo COVID-19 del Instituto de Salud Carlos III/Junta de Castilla y León. European Commission-NextGenerationEU, (Regulation EU 2020/2094), through CSIC’s Global Health Platform (PTI Salud Global). Plan Nacional de Salud y Farmacia Grant SAF2017-83079-R and Grant PID2020-113751RB-I00 funded by MCIN/AEI/ 10.13039/501100011033. Junta de Castilla y León/Fondo Social Europeo Grants. CSI035P17 and VA175P20. Proyecto SEAHORSE INFRARED: IR2020-1-UVA05.Peer reviewe