Abscisic Acid as an Emerging Modulator of the Responses of Plants to Low Oxygen Conditions

Different environmental and developmental cues involve low oxygen conditions, particularly those associated to abiotic stress conditions. It is widely accepted that plant responses to low oxygen conditions are mainly regulated by ethylene (ET). However, interaction with other hormonal signaling pathways as gibberellins (GAs), auxin (IAA), or nitric oxide (NO) has been well-documented. In this network of interactions, abscisic acid (ABA) has always been present and regarded to as a negative regulator of the development of morphological adaptations to soil flooding: hyponastic growth, adventitious root emergence, or formation of secondary aerenchyma in different plant species. However, recent evidence points toward a positive role of this plant hormone on the modulation of plant responses to hypoxia and, more importantly, on the ability to recover during the post-hypoxic period. In this work, the involvement of ABA as an emerging regulator of plant responses to low oxygen conditions alone or in interaction with other hormones is reviewed and discussed

From Classical to Modern Computational Approaches to Identify Key Genetic Regulatory Components in Plant Biology

The selection of plant genotypes with improved productivity and tolerance to environmental constraints has always been a major concern in plant breeding. Classical approaches based on the generation of variability and selection of better phenotypes from large variant collections have improved their efficacy and processivity due to the implementation of molecular biology techniques, particularly genomics, Next Generation Sequencing and other omics such as proteomics and metabolomics. In this regard, the identification of interesting variants before they develop the phenotype trait of interest with molecular markers has advanced the breeding process of new varieties. Moreover, the correlation of phenotype or biochemical traits with gene expression or protein abundance has boosted the identification of potential new regulators of the traits of interest, using a relatively low number of variants. These important breakthrough technologies, built on top of classical approaches, will be improved in the future by including the spatial variable, allowing the identification of gene(s) involved in key processes at the tissue and cell levels

Early Molecular Responses of Tomato to Combined Moderate Water Stress and Tomato Red Spider Mite Tetranychus evansi Attack

Interaction between plants and their environment is changing as a consequence of the climate change and global warming, increasing the performance and dispersal of some pest species which become invasive species. Tetranychus evansi also known as the tomato red spider mite, is an invasive species which has been reported to increase its performance when feeding in the tomato cultivar Moneymaker (MM) under water deficit conditions. In order to clarify the underlying molecular events involved, we examined early plant molecular changes occurring on MM during T. evansi infestation alone or in combination with moderate drought stress. Hormonal profiling of MM plants showed an increase in abscisic acid (ABA) levels in drought-stressed plants while salicylic acid (SA) levels were higher in drought-stressed plants infested with T. evansi, indicating that SA is involved in the regulation of plant responses to this stress combination. Changes in the expression of ABA-dependent DREB2, NCED1, and RAB18 genes confirmed the presence of drought-dependent molecular responses in tomato plants and indicated that these responses could be modulated by the tomato red spider mite. Tomato metabolic profiling identified 42 differentially altered compounds produced by T. evansi attack, moderate drought stress, and/or their combination, reinforcing the idea of putative manipulation of tomato plant responses by tomato red spider mite. Altogether, these results indicate that the tomato red spider mite acts modulating plant responses to moderate drought stress by interfering with the ABA and SA hormonal responses, providing new insights into the early events occurring on plant biotic and abiotic stress interaction

The Role of ABA in Plant Immunity is Mediated through the PYR1 Receptor

[EN] ABA is involved in plant responses to a broad range of pathogens and exhibits complex antagonistic and synergistic relationships with salicylic acid (SA) and ethylene (ET) signaling pathways, respectively. However, the specific receptor of ABA that triggers the positive and negative responses of ABA during immune responses remains unknown. Through a reverse genetic analysis, we identified that PYR1, a member of the family of PYR/PYL/RCAR ABA receptors, is transcriptionally upregulated and specifically perceives ABA during biotic stress, initiating downstream signaling mediated by ABA-activated SnRK2 protein kinases. This exerts a damping effect on SA-mediated signaling, required for resistance to biotrophic pathogens, and simultaneously a positive control over the resistance to necrotrophic pathogens controlled by ET. We demonstrated that PYR1-mediated signaling exerted control on a priori established hormonal cross-talk between SA and ET, thereby redirecting defense outputs. Defects in ABA/PYR1 signaling activated SA biosynthesis and sensitized plants for immune priming by poising SA-responsive genes for enhanced expression. As a trade-off effect,pyr1-mediated activation of the SA pathway blunted ET perception, which is pivotal for the activation of resistance towards fungal necrotrophs. The specific perception of ABA by PYR1 represented a regulatory node, modulating different outcomes in disease resistance.This research was founded by the Spanish AEI agency by grant BIO2017-82503-R to P.L.R. and by grant RTI2018-098501-B-I00 to P.V.García-Andrade, J.; González, B.; Gonzalez-Guzman, M.; Rodríguez Egea, PL.; Vera Vera, P. (2020). The Role of ABA in Plant Immunity is Mediated through the PYR1 Receptor. International Journal of Molecular Sciences. 21(16):1-21. https://doi.org/10.3390/ijms21165852S1212116Malamy, J., Carr, J. P., Klessig, D. F., & Raskin, I. (1990). Salicylic Acid: A Likely Endogenous Signal in the Resistance Response of Tobacco to Viral Infection. Science, 250(4983), 1002-1004. doi:10.1126/science.250.4983.1002Métraux, J. P., Signer, H., Ryals, J., Ward, E., Wyss-Benz, M., Gaudin, J., … Inverardi, B. (1990). Increase in Salicylic Acid at the Onset of Systemic Acquired Resistance in Cucumber. Science, 250(4983), 1004-1006. doi:10.1126/science.250.4983.1004Glazebrook, J. (2005). Contrasting Mechanisms of Defense Against Biotrophic and Necrotrophic Pathogens. Annual Review of Phytopathology, 43(1), 205-227. doi:10.1146/annurev.phyto.43.040204.135923Verhage, A., van Wees, S. C. M., & Pieterse, C. M. J. (2010). Plant Immunity: It’s the Hormones Talking, But What Do They Say?: Figure 1. Plant Physiology, 154(2), 536-540. doi:10.1104/pp.110.161570Broekaert, W. F., Delauré, S. L., De Bolle, M. F. C., & Cammue, B. P. A. (2006). The Role of Ethylene in Host-Pathogen Interactions. Annual Review of Phytopathology, 44(1), 393-416. doi:10.1146/annurev.phyto.44.070505.143440Grant, M. R., & Jones, J. D. G. (2009). Hormone (Dis)harmony Moulds Plant Health and Disease. Science, 324(5928), 750-752. doi:10.1126/science.1173771Pieterse, C. M. J., Van der Does, D., Zamioudis, C., Leon-Reyes, A., & Van Wees, S. C. M. (2012). Hormonal Modulation of Plant Immunity. Annual Review of Cell and Developmental Biology, 28(1), 489-521. doi:10.1146/annurev-cellbio-092910-154055Thaler, J. S., & Bostock, R. M. (2004). INTERACTIONS BETWEEN ABSCISIC-ACID-MEDIATED RESPONSES AND PLANT RESISTANCE TO PATHOGENS AND INSECTS. Ecology, 85(1), 48-58. doi:10.1890/02-0710Spoel, S. H., Koornneef, A., Claessens, S. M. C., Korzelius, J. P., Van Pelt, J. A., Mueller, M. J., … Pieterse, C. M. J. (2003). NPR1 Modulates Cross-Talk between Salicylate- and Jasmonate-Dependent Defense Pathways through a Novel Function in the Cytosol. The Plant Cell, 15(3), 760-770. doi:10.1105/tpc.009159Thomma, B. P. H. J., Eggermont, K., Tierens, K. F. M.-J., & Broekaert, W. F. (1999). Requirement of Functional Ethylene-Insensitive 2Gene for Efficient Resistance of Arabidopsis to Infection by Botrytis cinerea  . Plant Physiology, 121(4), 1093-1101. doi:10.1104/pp.121.4.1093Gu, Y.-Q., Yang, C., Thara, V. K., Zhou, J., & Martin, G. B. (2000). Pti4 Is Induced by Ethylene and Salicylic Acid, and Its Product Is Phosphorylated by the Pto Kinase. The Plant Cell, 12(5), 771-785. doi:10.1105/tpc.12.5.771Berrocal-Lobo, M., Molina, A., & Solano, R. (2002). Constitutive expression ofETHYLENE-RESPONSE-FACTOR1inArabidopsisconfers resistance to several necrotrophic fungi. The Plant Journal, 29(1), 23-32. doi:10.1046/j.1365-313x.2002.01191.xDı́az, J., ten Have, A., & van Kan, J. A. L. (2002). The Role of Ethylene and Wound Signaling in Resistance of Tomato to Botrytis cinerea  . Plant Physiology, 129(3), 1341-1351. doi:10.1104/pp.001453Leslie, C. A., & Romani, R. J. (1988). Inhibition of Ethylene Biosynthesis by Salicylic Acid. Plant Physiology, 88(3), 833-837. doi:10.1104/pp.88.3.833Chen, H., Xue, L., Chintamanani, S., Germain, H., Lin, H., Cui, H., … Zhou, J.-M. (2009). ETHYLENE INSENSITIVE3 and ETHYLENE INSENSITIVE3-LIKE1 Repress SALICYLIC ACID INDUCTION DEFICIENT2 Expression to Negatively Regulate Plant Innate Immunity in Arabidopsis    . The Plant Cell, 21(8), 2527-2540. doi:10.1105/tpc.108.065193Huang, P., Dong, Z., Guo, P., Zhang, X., Qiu, Y., Li, B., … Guo, H. (2019). Salicylic Acid Suppresses Apical Hook Formation via NPR1-Mediated Repression of EIN3 and EIL1 in Arabidopsis. The Plant Cell, 32(3), 612-629. doi:10.1105/tpc.19.00658Spoel, S. H., Johnson, J. S., & Dong, X. (2007). Regulation of tradeoffs between plant defenses against pathogens with different lifestyles. Proceedings of the National Academy of Sciences, 104(47), 18842-18847. doi:10.1073/pnas.0708139104Cutler, S. R., Rodriguez, P. L., Finkelstein, R. R., & Abrams, S. R. (2010). Abscisic Acid: Emergence of a Core Signaling Network. Annual Review of Plant Biology, 61(1), 651-679. doi:10.1146/annurev-arplant-042809-112122Mauch-Mani, B., & Mauch, F. (2005). The role of abscisic acid in plant–pathogen interactions. Current Opinion in Plant Biology, 8(4), 409-414. doi:10.1016/j.pbi.2005.05.015Asselbergh, B., De Vleesschauwer, D., & Höfte, M. (2008). Global Switches and Fine-Tuning—ABA Modulates Plant Pathogen Defense. Molecular Plant-Microbe Interactions®, 21(6), 709-719. doi:10.1094/mpmi-21-6-0709Fan, J., Hill, L., Crooks, C., Doerner, P., & Lamb, C. (2009). Abscisic Acid Has a Key Role in Modulating Diverse Plant-Pathogen Interactions      . Plant Physiology, 150(4), 1750-1761. doi:10.1104/pp.109.137943Sánchez-Vallet, A., López, G., Ramos, B., Delgado-Cerezo, M., Riviere, M.-P., Llorente, F., … Molina, A. (2012). Disruption of Abscisic Acid Signaling Constitutively Activates Arabidopsis Resistance to the Necrotrophic Fungus Plectosphaerella cucumerina    . Plant Physiology, 160(4), 2109-2124. doi:10.1104/pp.112.200154Adie, B. A. T., Pérez-Pérez, J., Pérez-Pérez, M. M., Godoy, M., Sánchez-Serrano, J.-J., Schmelz, E. A., & Solano, R. (2007). ABA Is an Essential Signal for Plant Resistance to Pathogens Affecting JA Biosynthesis and the Activation of Defenses in Arabidopsis. The Plant Cell, 19(5), 1665-1681. doi:10.1105/tpc.106.048041García-Andrade, J., Ramírez, V., Flors, V., & Vera, P. (2011). Arabidopsis ocp3 mutant reveals a mechanism linking ABA and JA to pathogen-induced callose deposition. The Plant Journal, 67(5), 783-794. doi:10.1111/j.1365-313x.2011.04633.xJensen, M. K., Hagedorn, P. H., de Torres-Zabala, M., Grant, M. R., Rung, J. H., Collinge, D. B., & Lyngkjaer, M. F. (2008). Transcriptional regulation by an NAC (NAM-ATAF1,2-CUC2) transcription factor attenuates ABA signalling for efficient basal defence towardsBlumeria graminisf. sp.hordeiin Arabidopsis. The Plant Journal, 56(6), 867-880. doi:10.1111/j.1365-313x.2008.03646.xDe Torres-Zabala, M., Truman, W., Bennett, M. H., Lafforgue, G., Mansfield, J. W., Rodriguez Egea, P., … Grant, M. (2007). Pseudomonas syringae pv. tomato hijacks the Arabidopsis abscisic acid signalling pathway to cause disease. The EMBO Journal, 26(5), 1434-1443. doi:10.1038/sj.emboj.7601575Mine, A., Berens, M. L., Nobori, T., Anver, S., Fukumoto, K., Winkelmüller, T. M., … Tsuda, K. (2017). Pathogen exploitation of an abscisic acid- and jasmonate-inducible MAPK phosphatase and its interception by Arabidopsis immunity. Proceedings of the National Academy of Sciences, 114(28), 7456-7461. doi:10.1073/pnas.1702613114Peng, Z., Hu, Y., Zhang, J., Huguet-Tapia, J. C., Block, A. K., Park, S., … White, F. F. (2019). Xanthomonas translucens commandeers the host rate-limiting step in ABA biosynthesis for disease susceptibility. Proceedings of the National Academy of Sciences, 116(42), 20938-20946. doi:10.1073/pnas.1911660116Chen, W., Provart, N. J., Glazebrook, J., Katagiri, F., Chang, H.-S., Eulgem, T., … Zhu, T. (2002). Expression Profile Matrix of Arabidopsis Transcription Factor Genes Suggests Their Putative Functions in Response to Environmental Stresses[W]. The Plant Cell, 14(3), 559-574. doi:10.1105/tpc.010410Anderson, J. P., Badruzsaufari, E., Schenk, P. M., Manners, J. M., Desmond, O. J., Ehlert, C., … Kazan, K. (2004). Antagonistic Interaction between Abscisic Acid and Jasmonate-Ethylene Signaling Pathways Modulates Defense Gene Expression and Disease Resistance in Arabidopsis. The Plant Cell, 16(12), 3460-3479. doi:10.1105/tpc.104.025833Yang, Z., Tian, L., Latoszek-Green, M., Brown, D., & Wu, K. (2005). Arabidopsis ERF4 is a transcriptional repressor capable of modulating ethylene and abscisic acid responses. Plant Molecular Biology, 58(4), 585-596. doi:10.1007/s11103-005-7294-5Dittrich, M., Mueller, H. M., Bauer, H., Peirats-Llobet, M., Rodriguez, P. L., Geilfus, C.-M., … Hedrich, R. (2019). The role of Arabidopsis ABA receptors from the PYR/PYL/RCAR family in stomatal acclimation and closure signal integration. Nature Plants, 5(9), 1002-1011. doi:10.1038/s41477-019-0490-0Hubbard, K. E., Nishimura, N., Hitomi, K., Getzoff, E. D., & Schroeder, J. I. (2010). Early abscisic acid signal transduction mechanisms: newly discovered components and newly emerging questions. Genes & Development, 24(16), 1695-1708. doi:10.1101/gad.1953910Klingler, J. P., Batelli, G., & Zhu, J.-K. (2010). ABA receptors: the START of a new paradigm in phytohormone signalling. Journal of Experimental Botany, 61(12), 3199-3210. doi:10.1093/jxb/erq151Raghavendra, A. S., Gonugunta, V. K., Christmann, A., & Grill, E. (2010). ABA perception and signalling. Trends in Plant Science, 15(7), 395-401. doi:10.1016/j.tplants.2010.04.006Umezawa, T., Sugiyama, N., Mizoguchi, M., Hayashi, S., Myouga, F., Yamaguchi-Shinozaki, K., … Shinozaki, K. (2009). Type 2C protein phosphatases directly regulate abscisic acid-activated protein kinases in Arabidopsis. Proceedings of the National Academy of Sciences, 106(41), 17588-17593. doi:10.1073/pnas.0907095106Vlad, F., Rubio, S., Rodrigues, A., Sirichandra, C., Belin, C., Robert, N., … Merlot, S. (2009). Protein Phosphatases 2C Regulate the Activation of the Snf1-Related Kinase OST1 by Abscisic Acid inArabidopsis . The Plant Cell, 21(10), 3170-3184. doi:10.1105/tpc.109.069179Fujii, H., Chinnusamy, V., Rodrigues, A., Rubio, S., Antoni, R., Park, S.-Y., … Zhu, J.-K. (2009). In vitro reconstitution of an abscisic acid signalling pathway. Nature, 462(7273), 660-664. doi:10.1038/nature08599Ma, Y., Szostkiewicz, I., Korte, A., Moes, D., Yang, Y., Christmann, A., & Grill, E. (2009). Regulators of PP2C Phosphatase Activity Function as Abscisic Acid Sensors. Science, 324(5930), 1064-1068. doi:10.1126/science.1172408Park, S.-Y., Fung, P., Nishimura, N., Jensen, D. R., Fujii, H., Zhao, Y., … Cutler, S. R. (2009). Abscisic Acid Inhibits Type 2C Protein Phosphatases via the PYR/PYL Family of START Proteins. Science, 324(5930), 1068-1071. doi:10.1126/science.1173041Umezawa, T., Sugiyama, N., Takahashi, F., Anderson, J. C., Ishihama, Y., Peck, S. C., & Shinozaki, K. (2013). Genetics and Phosphoproteomics Reveal a Protein Phosphorylation Network in the Abscisic Acid Signaling Pathway in Arabidopsis thaliana. Science Signaling, 6(270). doi:10.1126/scisignal.2003509Gonzalez-Guzman, M., Pizzio, G. A., Antoni, R., Vera-Sirera, F., Merilo, E., Bassel, G. W., … Rodriguez, P. L. (2012). Arabidopsis PYR/PYL/RCAR Receptors Play a Major Role in Quantitative Regulation of Stomatal Aperture and Transcriptional Response to Abscisic Acid. The Plant Cell, 24(6), 2483-2496. doi:10.1105/tpc.112.098574González-Guzmán, M., Rodríguez, L., Lorenzo-Orts, L., Pons, C., Sarrión-Perdigones, A., Fernández, M. A., … Rodríguez, P. L. (2014). Tomato PYR/PYL/RCAR abscisic acid receptors show high expression in root, differential sensitivity to the abscisic acid agonist quinabactin, and the capability to enhance plant drought resistance. Journal of Experimental Botany, 65(15), 4451-4464. doi:10.1093/jxb/eru219Helander, J. D. M., Vaidya, A. S., & Cutler, S. R. (2016). Chemical manipulation of plant water use. Bioorganic & Medicinal Chemistry, 24(3), 493-500. doi:10.1016/j.bmc.2015.11.010Antoni, R., Gonzalez-Guzman, M., Rodriguez, L., Rodrigues, A., Pizzio, G. A., & Rodriguez, P. L. (2011). Selective Inhibition of Clade A Phosphatases Type 2C by PYR/PYL/RCAR Abscisic Acid Receptors    . Plant Physiology, 158(2), 970-980. doi:10.1104/pp.111.188623Tischer, S. V., Wunschel, C., Papacek, M., Kleigrewe, K., Hofmann, T., Christmann, A., & Grill, E. (2017). Combinatorial interaction network of abscisic acid receptors and coreceptors fromArabidopsis thaliana. Proceedings of the National Academy of Sciences, 114(38), 10280-10285. doi:10.1073/pnas.1706593114Antoni, R., Gonzalez-Guzman, M., Rodriguez, L., Peirats-Llobet, M., Pizzio, G. A., Fernandez, M. A., … Rodriguez, P. L. (2012). PYRABACTIN RESISTANCE1-LIKE8 Plays an Important Role for the Regulation of Abscisic Acid Signaling in Root      . Plant Physiology, 161(2), 931-941. doi:10.1104/pp.112.208678Fujii, H., Verslues, P. E., & Zhu, J.-K. (2007). Identification of Two Protein Kinases Required for Abscisic Acid Regulation of Seed Germination, Root Growth, and Gene Expression in Arabidopsis. The Plant Cell, 19(2), 485-494. doi:10.1105/tpc.106.048538García-Andrade, J., Ramírez, V., López, A., & Vera, P. (2013). Mediated Plastid RNA Editing in Plant Immunity. PLoS Pathogens, 9(10), e1003713. doi:10.1371/journal.ppat.1003713Rubio, S., Rodrigues, A., Saez, A., Dizon, M. B., Galle, A., Kim, T.-H., … Rodriguez, P. L. (2009). Triple Loss of Function of Protein Phosphatases Type 2C Leads to Partial Constitutive Response to Endogenous Abscisic Acid      . Plant Physiology, 150(3), 1345-1355. doi:10.1104/pp.109.137174Schweighofer, A., Hirt, H., & Meskiene, I. (2004). Plant PP2C phosphatases: emerging functions in stress signaling. Trends in Plant Science, 9(5), 236-243. doi:10.1016/j.tplants.2004.03.007Carrasco, J. L. (2003). A novel transcription factor involved in plant defense endowed with protein phosphatase activity. The EMBO Journal, 22(13), 3376-3384. doi:10.1093/emboj/cdg323Carrasco, J. L., Castelló, M. J., Naumann, K., Lassowskat, I., Navarrete-Gómez, M., Scheel, D., & Vera, P. (2014). Arabidopsis Protein Phosphatase DBP1 Nucleates a Protein Network with a Role in Regulating Plant Defense. PLoS ONE, 9(3), e90734. doi:10.1371/journal.pone.0090734Clarke, J. D., Volko, S. M., Ledford, H., Ausubel, F. M., & Dong, X. (2000). Roles of Salicylic Acid, Jasmonic Acid, and Ethylene in cpr-Induced Resistance in Arabidopsis. The Plant Cell, 12(11), 2175-2190. doi:10.1105/tpc.12.11.2175Wildermuth, M. C., Dewdney, J., Wu, G., & Ausubel, F. M. (2001). Isochorismate synthase is required to synthesize salicylic acid for plant defence. Nature, 414(6863), 562-565. doi:10.1038/35107108Garcion, C., Lohmann, A., Lamodière, E., Catinot, J., Buchala, A., Doermann, P., & Métraux, J.-P. (2008). Characterization and Biological Function of the ISOCHORISMATE SYNTHASE2 Gene of Arabidopsis. Plant Physiology, 147(3), 1279-1287. doi:10.1104/pp.108.119420Mauch-Mani, B., Baccelli, I., Luna, E., & Flors, V. (2017). Defense Priming: An Adaptive Part of Induced Resistance. Annual Review of Plant Biology, 68(1), 485-512. doi:10.1146/annurev-arplant-042916-041132Gaffney, T., Friedrich, L., Vernooij, B., Negrotto, D., Nye, G., Uknes, S., … Ryals, J. (1993). Requirement of Salicylic Acid for the Induction of Systemic Acquired Resistance. Science, 261(5122), 754-756. doi:10.1126/science.261.5122.754Cheng, W.-H., Endo, A., Zhou, L., Penney, J., Chen, H.-C., Arroyo, A., … Sheen, J. (2002). A Unique Short-Chain Dehydrogenase/Reductase in Arabidopsis Glucose Signaling and Abscisic Acid Biosynthesis and Functions. The Plant Cell, 14(11), 2723-2743. doi:10.1105/tpc.006494Koiwai, H., Nakaminami, K., Seo, M., Mitsuhashi, W., Toyomasu, T., & Koshiba, T. (2004). Tissue-Specific Localization of an Abscisic Acid Biosynthetic Enzyme, AAO3, in Arabidopsis. Plant Physiology, 134(4), 1697-1707. doi:10.1104/pp.103.036970Endo, A., Koshiba, T., Kamiya, Y., & Nambara, E. (2008). Vascular system is a node of systemic stress responses. Plant Signaling & Behavior, 3(12), 1138-1140. doi:10.4161/psb.3.12.7145Endo, A., Sawada, Y., Takahashi, H., Okamoto, M., Ikegami, K., Koiwai, H., … Nambara, E. (2008). Drought Induction of Arabidopsis 9-cis-Epoxycarotenoid Dioxygenase Occurs in Vascular Parenchyma Cells    . Plant Physiology, 147(4), 1984-1993. doi:10.1104/pp.108.116632Alvarez, M. E., Pennell, R. I., Meijer, P.-J., Ishikawa, A., Dixon, R. A., & Lamb, C. (1998). Reactive Oxygen Intermediates Mediate a Systemic Signal Network in the Establishment of Plant Immunity. Cell, 92(6), 773-784. doi:10.1016/s0092-8674(00)81405-1Yu, A., Lepere, G., Jay, F., Wang, J., Bapaume, L., Wang, Y., … Navarro, L. (2013). Dynamics and biological relevance of DNA demethylation in Arabidopsis antibacterial defense. Proceedings of the National Academy of Sciences, 110(6), 2389-2394. doi:10.1073/pnas.1211757110Flors, V., Ton, J., Van Doorn, R., Jakab, G., García-Agustín, P., & Mauch-Mani, B. (2007). Interplay between JA, SA and ABA signalling during basal and induced resistance against Pseudomonas syringae and Alternaria brassicicola. The Plant Journal, 54(1), 81-92. doi:10.1111/j.1365-313x.2007.03397.xPétriacq, P., Stassen, J. H. M., & Ton, J. (2016). Spore Density Determines Infection Strategy by the Plant Pathogenic Fungus Plectosphaerella cucumerina. Plant Physiology, 170(4), 2325-2339. doi:10.1104/pp.15.00551Koornneef, A., & Pieterse, C. M. J. (2008). Cross Talk in Defense Signaling. Plant Physiology, 146(3), 839-844. doi:10.1104/pp.107.112029Ton, J., Flors, V., & Mauch-Mani, B. (2009). The multifaceted role of ABA in disease resistance. Trends in Plant Science, 14(6), 310-317. doi:10.1016/j.tplants.2009.03.006De Vleesschauwer, D., Yang, Y., Vera Cruz, C., & Höfte, M. (2010). Abscisic Acid-Induced Resistance against the Brown Spot Pathogen Cochliobolus miyabeanus in Rice Involves MAP Kinase-Mediated Repression of Ethylene Signaling      . Plant Physiology, 152(4), 2036-2052. doi:10.1104/pp.109.152702De Torres Zabala, M., Bennett, M. H., Truman, W. H., & Grant, M. R. (2009). Antagonism between salicylic and abscisic acid reflects early host-pathogen conflict and moulds plant defence responses. The Plant Journal, 59(3), 375-386. doi:10.1111/j.1365-313x.2009.03875.xBelin, C., de Franco, P.-O., Bourbousse, C., Chaignepain, S., Schmitter, J.-M., Vavasseur, A., … Thomine, S. (2006). Identification of Features Regulating OST1 Kinase Activity and OST1 Function in Guard Cells  . Plant Physiology, 141(4), 1316-1327. doi:10.1104/pp.106.079327Planes, M. D., Niñoles, R., Rubio, L., Bissoli, G., Bueso, E., García-Sánchez, M. J., … Serrano, R. (2014). A mechanism of growth inhibition by abscisic acid in germinating seeds of Arabidopsis thaliana based on inhibition of plasma membrane H+-ATPase and decreased cytosolic pH, K+, and anions. Journal of Experimental Botany, 66(3), 813-825. doi:10.1093/jxb/eru44

New Perspectives for Electrodialytic Remediation

Electrodialytic remediation has been widely used for the recovery of different contaminants from numerous matrices, such as, for example, polluted soils, wastewater sludge, fly ash, mine tailing or harbour sediments. The electrodialytic remediation is an enhancement of the electrokinetic remediation technique, and it consists of the use of ion-exchange membranes for the control of the acid and the alkaline fronts generated in the electrochemical processes. While the standard electrodialytic cell is usually built with three-compartment configuration, it has been shown that for the remediation of matrices that require acid environment, a two-compartment cell has given satisfactory removal efficiencies with reduced energy costs. Recycling secondary batteries, with growing demand, has an increasing economic and environmental interest. This work focusses on the proposal of the electrodialytic remediation technique as a possible application for the recycling of lithium-ion cells and other secondary batteries. The recovery of valuable components, such as lithium, manganese, cobalt of phosphorous, based on current recycling processes and the characterization of solid waste is addressed.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges the financial support from the University of Malaga, project: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the funding from the University of Malaga for the postdoctoral fellowship PPIT.UMA.A.3.2.2018. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Electrodialytic Recovery of Cobalt from Spent Lithium-Ion Batteries

Contribución en congreso científicoRecycling lithium-ion batteries has an increasing interest for economic and environmental reasons. Disposal of lithium-ion batteries imposes high risk to the environment due to the toxicity of some of their essential components. In addition to this, some of these components, such as cobalt, natural graphite and phosphorus, are included in the list of critical raw materials for the European Union due to their strategic importance in the manufacturing industry. Therefore, in the recent years, numerous research studies have been focused on the development of efficient processes for battery recycling and the selective recuperation of these key components. LiCoO2 is the most common material use in current lithium-ion batteries cathodes. In the current work, an electrodialytic method is proposed for the recovery of cobalt from this kind of electrode. In a standard electrodialytic cell, the treated matrix is separated from the anode and the cathode compartments by means of ion-exchange membranes. A cation-exchange membrane (CEM) allows the passage of cations and hinders the passage of anions, while the behaviour of anion-exchange membrane (AEM) does the opposite. A three-compartment electrodialytic cell has been designed and assembled, as depicted in the figure. In the central compartment, a suspension of LiCoO2 is added. Different extracting agents, such as EDTA, HCl and HNO3, are tested to enhanced the dissolution and the selective extraction of the target metal. Dissolved cobalt-containing complexes migrate towards the cathode or the anode compartments depending on the ionic charge of the complexes. While cobalt extraction via extracting agents is an expensive treatment, as it requires the constant addition of chemicals, an efficient electrodialytic cell could allow the recirculation of the extracting agents and the economical optimization of the process.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges the financial support from the University of Malaga, project: PPIT.UMA.B5.2018/17. Villen-Guzman acknowledges the funding from the University of Malaga for the postdoctoral fellowship PPIT.UMA.A.3.2.2018. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Acid leaching of LiCoO2 enhanced by reducing agent. Model formulation and validation.

In this work, a model has been formulated to describe the complex process of LiCoO2 leaching through the participation of competing reactions in acid media including the effect of H2O2 as reducing agent. The model presented here describes the extraction of Li and Co in the presence and absence of H2O2, and it takes into account the different phenomena affecting the controlling mechanisms. In this context, the model predicts the swift from kinetic control to diffusion control. The model has been implemented and solved to simulate the leaching process. To validate the model and to estimate the model parameters, a set of 12 (in triplicate) extraction experiments were carried out varying the concentration of hydrochloric acid (within the range of 0.5–2.5 M) and hydrogen peroxide (range 0–0.6%v/v). The simulation results match fairly well with the experimental data for a wide range of conditions. Furthermore, the model can be used to predict results with different solid-liquid ratios as well as different acid and oxygen peroxide concentrations. This model could be used to design or optimize a LiCoO2 extraction process facilitating the corresponding economical balance of the treatment.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska- Curie grant agreement No. 778045 and the “Proyectos I+D+i en el marco del Programa Operativo FEDER Andalucía 2014–2020”, Project no. UMA18-FEDERJA-279. Cerrillo-Gonzalez acknowledges the FPU grant (FPU18/04295) obtained from the Spanish Ministry of Education. Funding for open access charge: Universidad de Málaga / CBUA

Alternative reducing agents for Lithium-Ion batteries recycling via hydrometallurgical process

Lithium-ion batteries (LIB) are a key factor in the transition to a decarbonised and clean energy system due to their application in the power sector and electric transport. However, a growing demand of these batteries involves two direct problems: an increase in the generation of spent LIBs as well as in the demand of raw materials. Hence, the development of efficient recycling treatment of LIBs is crucial to make them a true enabler of the green transition. Currently, the LIBs recycling process can be divided into pyrometallurgical and hydrometallurgical. The first one is based on the treatment of LIBs at high temperatures to produces metal pyrolysis and metal reduction, while the second method consists in the recovery of metals via acidic leaching. Although pyrometallurgical method is the most used in the industry, hydrometallurgical process presents a series of advantages, such as low energy consumption, high metal recovery and high product purity, that make it more promising in the search of more effective recycling method. In the hydrometallurgical process, the addition of acids and reducing agents is required to dissolve the solid particles and extract the valuable metals. The purpose of this work was to evaluate the effect of alternative reducing agent in the leaching process to maximize the amount of metal (Mn, Li, Ni, Co) recovered from a real LIBs waste. With this aim, the leaching processes were carried out using as reducing agent H2O2, Fe and NH4Cl. According to the experimental results, Fe and NH4Cl enhance the extraction yield as well as the reaction time comparing with the results obtain using H2O2.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Hydrometallurgical extraction of Li and Co from LiCoO2 particles–Experimental and Modeling

The use of lithium-ion batteries as energy storage in portable electronics and electric vehicles is increasing rapidly, which involves the consequent increase of battery waste. Hence, the development of reusing and recycling techniques is important to minimize the environmental impact of these residues and favor the circular economy goal. This paper presents experimental and modeling results for the hydrometallurgical treatment for recycling LiCoO2 cathodes from lithium-ion batteries. Previous experimental results for hydrometallurgical extraction showed that acidic leaching of LiCoO2 particles produced a non-stoichiometric extraction of lithium and cobalt. Furthermore, the maximum lithium extraction obtained experimentally seemed to be limited, reaching values of approximately 65–70%. In this paper, a physicochemical model is presented aiming to increase the understanding of the leaching process and the aforementioned limitations. The model describes the heterogeneous solid–liquid extraction mechanism and kinetics of LiCoO2 particles under a weakly reducing environment. The model presented here sets the basis for a more general theoretical framework that would describe the process under different acidic and reducing conditions. The model is validated with two sets of experiments at different conditions of acid concentration (0.1 and 2.5 M HCl) and solid to liquid ratio (5 and 50 g L−1). The COMSOL Multiphysics program was used to adjust the parameters in the kinetic model with the experimental results.This work has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 778045. Paz-Garcia acknowledges financial support from the program “Proyectos I+D+i en el marco del Programa Operativo FEDER Andalucía 2014–2020”, No. UMA18-FEDERJA-279. Cerrillo-Gonzalez acknowledges the FPU grant obtained from the Spanish Ministry of Education. The University of Malaga is acknowledged for the financial support in the postdoctoral fellowship of Villen-Guzman

Leaching of LiCoO2 using H2O2 as reductant

The growing use of Lithium-Ion batteries (LIBs) in the field of electric vehicles and renewable energy storage entails the production of toxic and environmental hazardous wastes. Furthermore, some components in these batteries are classified as Critical Raw Material due to their supply risk and economic importance. Hence, the development of more efficient process to recycle LIBs is gaining importance for economic aspects and environmental protection. In this work, the hydrometallurgical leaching process for the recovery of valuable metals from the cathode active materials of spent LIBs batteries was evaluated. Batch Experiments were carried out using LiCoO2 which is one of the most used cathodes in lithium-ion batteries. The selection of the extracting agent, its concentration, the reducing agent and the solid-liquid ratio are some of the parameters under study in this research. Hydrochloric acid was used as the extracting agent and its concentration was modified from 0.1 M to 2.5 M while solid-liquid ratio (50 g/L), temperature (25 ºC) were fixed in all of them. The percentage of metal extracted was 31% of Co and 66% of Li for 0.1 M HCl solution. Extraction with 2.5M HCl solution was similar, 35% and 71% of Co and Li, respectively, but extracted in just 90 min, unlike the 72 h in the previous test. An experiment using H2O2 as a reducing agent was also performed, reaching a high percentage of metal extracted: 93% of Co and 100% of Li for a 0.6%vol of H2O2 Although tests have been carried out using LiCoO2, the technique can be applied to different kinds of cathode from spent batteries. The results suggested that the recovery of Co and Li is viable at optimized experimental conditions. The results indicated clearly that the dissolution of LiCoO2 particles is faster and more extensive when using more acidic extracting solution and stronger reducing agents, such as hydrogen peroxide.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech