Regulación de la homeostasis iónica por los complejos TORC1 y TORC2

[ES] Estudio a nivel molecular de la relación de la ruta TOR con la H+-ATPasa en levadura. Caracterización de sus complejos y determinar su relación con otras funciones celulares como el transporte de iones y la regulación del citoesqueleto.[EN] Study (molecular level) of the relationship between pathway TOR and H+-ATPase in yeast. Characterization of the complex and determine its relationship to other cellular functions such as ion transport and regulation of cytoskeleton.Cabedo López, M. (2012). Regulación de la homeostasis iónica por los complejos TORC1 y TORC2. http://hdl.handle.net/10251/17985Archivo delegad

Caracterización de la regulación de la protón ATPasa PMA1 por parte de la ruta TOR en levadura "Saccharomyces cerevisiae"

[CA] El present treball pretén caracteritzar la regulació de la protó ATPasa PMA1 per part de la ruta TOR en el llevat S. cerevisiae. La ruta de senyalització depenent de la proteïna quinasa TOR és la principal responsable del control del creixement cel·lular en presència de nutrients. La H+-ATPasa es la responsable de la formació del gradient electroquímic de la membrana plasmàtica. La seva activitat correlaciona amb el creixement cel·lular i s’activa, principalment, per glucosa. Donat que la protó ATPasa s’activa per nutrients i que la proteïna TOR és responsable de la regulació en funció de l’estat de nutrients de la cèl·lula, es pot establir la hipòtesis que a nivell molecular ha d’haver una interconnexió entre aquestes dues rutes. En el present treball s'ha estudiat la protó ATPasa de rent (PMA1) a tres nivells diferents (expressió del gen, quantitat de proteïna i activitat de la proteïna). Donat que la proteïna TOR pot formar part de dos complexos diferents (TORC1 i TORC2) i que cada un té una funció diferent i unes dianes de regulació diferents, hem emprat mutants amb al·lels termosensibles per a TORC1 o TORC2 així com amb cèl·lules tractades amb rapamicina (inhibició específica de TORC1). Les nostres anàlisis han permès determinar que tant l’expressió del gen com la quantitat i l’activitat de la proteïna cau respecte als controls al inhibir TORC1. Quan s'inhibeix TORC2, l’efecte sobre la protó ATPasa es perceptible, però molt lleuger, i no es pot descartar que es tracte d’un efecte indirecte. Per tant, es pot concloure que TORC1 activa l’expressió del gen PMA1, que codifica la H+-ATPasa de membrana plasmàtica en Saccharomyces cerevisiae.[ES] El presente trabajo pretende caracterizar la regulación de la protón ATPasa PMA1 por parte de la ruta TOR en levadura S. cerevisiae. La ruta de señalización dependiente de la proteína quinasa TOR es la principal responsable del control del crecimiento celular en presencia de nutrientes. La H+-ATPasa es la responsable de la formación del gradiente electroquímico de la membrana plasmática. Su actividad correlaciona con el crecimiento celular y se activa, principalmente, por glucosa. Dado que la protón ATPasa se activa por nutrientes y TOR es responsable de la regulación en función del estado nutricional de la célula, podemos plantear la hipótesis que a nivel molecular debe haber una interconexión entre estas dos rutas. En el presente trabajo hemos estudiado la protón ATPasa de levadura (PMA1) a tres niveles diferentes (expresión del gen, cantidad de proteína y actividad de la proteína). Puesto que la proteína TOR puede formar parte de dos complejos diferentes (TORC1 y TORC2) y que cada uno tiene una función diferente y unas dianas de regulación diferentes, hemos utilizado mutantes con alelos termosensible para TORC1 o TORC2 así como con células tratadas con rapamicina (inhibición específica de TORC1). Tras los análisis hemos determinado que tanto la expresión del gen como la cantidad y actividad de la protón ATPasa disminuye respecto a los controles cuando inhibimos TORC1. Cuando inhibimos el complejo TORC2, el efecto sobre la protón ATPasa es perceptible, pero muy ligero, y no podemos descartar que se trate de un efecto indirecto. Por tanto, podemos concluir que TORC1 activa la expresión del gen PMA1 que codifica la H+- ATPasa de membrana plasmática en Saccharomyces cerevisiae.[EN] This work aims at characterizing the TOR dependent regulation of the plasma membrane H+-ATPase PMA1 in the baker’s yeast S. cerevisiae. The signalling pathway dependent on the TOR protein kinase is the main controller of cell growth in the presence of nutrients. The H+-ATPase is the responsible of forming the plasma membrane electrochemical gradient. Its activity correlates with cell growth, and is activated, mainly, by glucose. Given that the H+-ATPasa is activated by nutrients and that TOR is in charge of the regulation depending on the cell nutritional status, we can propose the hypothesis that at the molecular level there must be a cross talk between these two pathways. In the present work we have studied the H+ ATPase of yeast (PMA1) at three different levels (gene expression, amount of protein and protein activity). As TOR can be found in two different protein complexes (TORC1 y TORC2) and that each one has a different role and different targets, we have used mutants carrying thermosensitive alleles for TORC1 or TORC2 as well as cells treated with rapamycin (specific inhibition of TORC1). Our analysis have determined that gene expression, and therefore amount and H+-ATPase activity is decreased compared to control cells upon inhibition of TORC1. Inhibition of TORC2 has a much lesser effect and we cannot discard that is due to an indirect effect. Therfore, we can concluye that TORC1 activates the expresión.Cabedo López, M. (2010). Caracterización de la regulación de la protón ATPasa PMA1 por parte de la ruta TOR en levadura "Saccharomyces cerevisiae". http://hdl.handle.net/10251/18485.Archivo delegad

Zoophytophagous mites can trigger plant‐genotype specific defensive responses affecting potential prey beyond predation: the case of Euseius stipulatus and Tetranychus urticae in citrus

Background Zoophytophagous predators can trigger plant defenses affecting prey populations beyond predation. Euseius stipulatus is a presumed zoophytophagous phytoseiid common in citrus. The response of citrus to one of its potential prey, Tetranychus urticae, is genotype dependent, with Citrus reshni and C. aurantium exhibiting extreme susceptibility and resistance, respectively. Volatile blends produced upon infestation affected the behavior of these two mites. We wondered whether E. stipulatus could trigger similar responses. Results Euseius stipulatus triggered genotype‐dependent defense responses in citrus. Whereas C. aurantium upregulated the Jasmonic Acid, Salicylic Acid and flavonoids defensive pathways, C. reshni upregulated JA only. Likewise, different volatile blends were induced. These blends were exploited by E. stipulatus to select less‐defended plants (i.e., those in which higher pest densities are expected) and, interestingly, did not prevent T. urticae from choosing E. stipulatus‐infested plants. To the best of our knowledge, this is the first time that this type of response has been described for a zoophytophagous phytoseiid. Conclusion The observed responses could affect herbivore populations through plant‐mediated effects. Although further research is needed to fully characterize them and include other arthropods in the system, these results open opportunities for more sustainable and effective pest control methods (i.e., combining semiochemicals and biological control

Role of the yeast multidrug transporter Qdr2 in cation homeostasis and the oxidative stress response

We have identified QDR2 in a screening for genes able to confer tolerance to sodium and/or lithium stress upon overexpression. Qdr2 is a multidrug transporter of the major facilitator superfamily, originally described for its ability to transport the antimalarial drug quinidine and the herbicide barban. To identify its physiological substrate, we have screened for phenotypes dependent on QDR2 and found that Qdr2 is able to transport monovalent and divalent cations with poor selectivity, as shown by growth tests and the determination of internal cation content. Moreover, strains overexpressing or lacking QDR2 also exhibit phenotypes when reactive oxygen species- producing agents, such as hydrogen peroxide or menadione were added to the growth medium. We have also found that the presence of copper and hydrogen peroxide repress the expression of QDR2. In addition, the copper uptake of a qdr2 mutant strain is similar to a wild type, but the extrusion is clearly impaired. Based on our results, we propose that free divalent copper is the main physiological substrate of Qdr2. As copper is a substrate for several redox reactions that occur within the cytoplasm, its function in copper homeostasis explains its role in the oxidative stress response.This work was supported by grants PAID-06-10-1496 of the Universitat Politècnica de València (Valencia, Spain), PROMETEO/2010/038 of the ‘Consellería de Educación’ (Valencia, Spain), by grant BFU2011-30197-C03-03 and by grant BFU2011-22526 from the Ministerio de Ciencia e Innovación (Madrid, Spain)

Molecular characterization of Cardinium, Rickettsia, Spiroplasma and Wolbachia in mite species from citrus orchards

Tetranychidae spider mites are considered key citrus pests in some production areas, especially Tetranychus urticae Koch. Over the past decades, pesticide overuse seems to have promoted T. urticae population selection in citrus orchards. However, the microbiota has also been pointed out as a plausible explanation for population structure or plant host specialisation observed in several arthropod species. In this work, we have determined the incidence of Cardinium, Rickettsia, Spiroplasma and Wolbachia as representatives of major distorter bacteria genera in Aplonobia histricina (Berlese), Eutetranychus banksi (McGregor), Eutetranychus orientalis (Klein), Panonychus citri (McGregor), Tetranychus evansi Baker and Pritchard, Tetranychus turkestani Ugarov and Nikolskii, and T. urticae populations from Spanish citrus orchards. Only Wolbachia was detected by PCR. The multilocus alignment approach and phylogenetic inference indicated that all detected Wolbachia belong to supergroup B. The deep analysis of each 16S rDNA, ftsZ and wsp gene sequences allowed identifying several phylogenetically diferent Wolbachia sequences. It probably indicates the presence of several diferent races or strains, all of them belonging to supergroup B. The wsp sequence typing analysis unveiled the presence of the two already identifed alleles (61 and 370) and allowed to contribute with fve new alleles, supporting the presence of diferent but related B-races in the studied mite populations. The results are discussed and related to T. urticae population structure, previously observed in Spanish citrus orchards

The olfactive responses of Tetranychus urticae natural enemies in citrus depend on plant genotype, prey presence, and their diet specialization

[EN] Sour orange, Citrus aurantium, displays higher constitutive and earlier inducible direct defenses against the two-spotted spider mite, Tetranychus urticae, than Cleopatra mandarin, Citrus reshni. Moreover, herbivore-induced plant volatiles (HIPVs) produced by sour orange upon infestation can induce resistance in Cleopatra mandarin but not vice versa. Because the role of these HIPVs in indirect resistance remains ignored, we have carried out a series of behavioral assays with three predatory mites with different levels of specialization on this herbivore, from strict entomophagy to omnivory. We have further characterized the volatile blend associated with T. urticae, which interestingly includes the HIPV methyl salicylate, as well as that produced by induced Cleopatra mandarin plants. Although a preference for less defended plants with presumably higher prey densities (i.e., C. reshni) was expected, this was not always the case. Because predators' responses changed with diet width, with omnivore predators responding to both HIPVs and prey-related odors and specialized ones mostly to prey, our results reveal that these responses depend on plant genotype, prey presence and predator diet specialization. As the different volatile blends produced by infested sour orange, induced Cleopatra mandarin and T. urticae itself are attractive to T. urticae natural enemies but not to the herbivore, they may provide clues to develop new more sustainable tools to manipulate these agriculturally relevant species.The research leading to these results was partially funded by the Spanish Ministry of Economy and Competitiveness (AGL2014-55616-C3; AGL2015-64990-2R). The authors thank M. Piquer (UJI) for technical assistance. MC received a pre-doctoral fellowship from the Spanish Ministry of Economy and Competitiveness (BES-2015-074570), and MP was the recipient of a research fellowship from INIA, Spain (subprogram DOC INIA-CCAA).Cabedo López, M.; Cruz-Miralles, J.; Vacas, S.; Navarro-Llopis, V.; Pérez-Hedo, M.; Flors, V.; Jaques, JA. (2019). The olfactive responses of Tetranychus urticae natural enemies in citrus depend on plant genotype, prey presence, and their diet specialization. Journal of Pest Science. 92(3):1165-1177. https://doi.org/10.1007/s10340-019-01107-7S1165117792

From virus resistance to arthropod susceptibility

Resumen de la ponencia presentada en el Annual Meeting on Crop-arthropod-microorganism interactions (CAMo), celabrado en Ljubljana, January 31st to February 2nd, 201

Plant defense responses triggered by phytoseiid predatory mites (Mesostigmata: Phytoseiidae) are species-specific, depend on plant genotype and may not be related to direct plant feeding

Zoophytophagous arthropods can elicit plant defense responses affecting potential prey beyond predation. Phytophagy prevails as the main trigger for these responses, as in the case of Euseius stipulatus (Athias-Henriot) (Mesostigmata: Phytoseiidae), a predator occurring in citrus. Because other triggers cannot be excluded, our aim was to examine whether other phytoseiids co-occurring with E. stipulatus but not engaged in plant feeding [Neoseiulus californicus (McGregor) and Phytoseiulus persimilis Athias-Henriot] could induce similar responses (in terms of herbivore induced plant volatiles, HIPVs, and main defensive pathways), and how these affected the behavior of conspecifics and the shared prey, Tetranychus urticae Koch (Prostigmata: Tetranychidae). N. californicus triggered plant genotype-specific defense responses, including the production of different HIPVs compared to clean plants. However, we could not observe these effects for P. persimilis. T. urticae avoided better protected plants, because of stronger direct or indirect defense. As plants with weaker direct defense levels should offer higher prey densities, and those harboring conspecific predators represent higher risk of cannibalism, predators were expected to behave similarly. However, they did not. Our results demonstrate that plant defense triggered by phytoseiids is species-specific, depend on plant genotype and can be triggered by non-feeding activities. As N. californicus is a highly efficient predator used worldwide, further studies with this species are needed. Likewise, cineol, one of the volatiles identified in the blends triggered by this phytoseiid, could be used to manipulate the prey. These studies could pave the way for a more efficient use of phytoseiids in agroecosystems

L'hort escolar com a ferramenta multidisciplinària per a l’aprenentatge actiu i cooperatiu de les Ciències Naturals.

Treball Final de Màster Universitari en Professor/a d'Educació Secundària Obligatòria i Batxillerat, Formació Professional i Ensenyaments d'Idiomes. Codi: SAP139. Curs: 2016/2017Amb aquest treball final de màster pretenem posar en pràctica les idees i recursos que hem anat adquirint durant el període de formació com a futur s docents. Es pretén aplicar els no us corrents de l’educació perquè l’ensenyança estiga basada en l’experiència, la inda gació i l’aprenentatge constructivista. Així, el docent serà el guia que ajude l’alumne a arribar al coneixement. Per aquestes raons, he dissenyat uns materials didàctics basats en un hort escolar on els alumnes i els professors treballaran diferents aspe ctes i continguts de l’assignatura de Biologia i Geologia, així com també es pot fer arribar a altres departament s del centre. Utilitzant diverses metodologies i formes de treball en equip, els alumn es s’encarregaran de la cura de l’hort escolar i a més , s ervirà d’espai d’investigació i estudi per als continguts del currículum