The donor side of Photosystem II as the copper-inhibitory binding site

We have measured, under Cu (II) toxicity conditions, the oxygen-evolving capacity of spinach PS II particles in the Hill reactions H2O -> SiMo (in the presence and absence of DCMU) and H2O -> PPBQ, as well as the fluorescence induction curve of Tris-washed spinach PS II particles. Cu (II) inhibits both Hill reactions and, in the first case, the DCMU-insensitive H2O -> SiMo activity. In addition, the variable fluorescence is lowered by Cu (II). We have interpreted our results in terms of a donor side inhibition close to the reaction center. The same polarographic and fluorescence measurements carried out at different pHs indicate that Cu (II) could bind to amino acid residues that can be protonated and deprotonated. In order to reverse the Cu (II) inhibition by a posterior EDTA treatment, in experiments of preincubation of PS II particles with Cu (II) in light we have demonstrated that light is essential for the damage due to Cu (II) and that this furthermore is irreversible.This work was supported by a grant from the Spanish DGICYT (PB94-0116). J.B. Arellano was the recipient of a fellowship from the Spanish Science and Education Ministry.Peer reviewe

Diagnosis of the infection of sunflower by Orobanche cumana using multicolour fluorescence imaging

Orobanche cumana is an holoparasite and thus totally dependent on sunflower for fixed carbon. Initial stages of the infection occur in the first weeks after sowing and are critical for the establishment of a continuum between the host and the parasite vascular system. From that moment the parasite obtains its supply of water, mineral nutrients, and assimilates from the host plant. Alterations of plant metabolism can be detected using remote sensing techniques for detection of fluorescence emitted by plants. One of these indirect techniques is multicolour fluorescence imaging. In this work, we assessed the early infection of sunflower by O. cumana using multicolour fluorescence imaging and we inferred physiological processes affected in sunflower plants infected by the parasite. Ten germinated seeds of the inbred line NR5 were inoculated with population LP2013 of O. cumana. The same number of not inoculated seeds was used as control. Sunflower was planted in pots with soil mixture and grown in greenhouse at 12–22°C for 6 weeks. Multicolour fluorescence imaging was conducted 3, 4, and 5 weeks after inoculation. The two first pairs of fully expanded leaves of each sunflower plant were imaged, and, for each measure date, five fluorescence variables in inoculated plants were compared to those in the control. Three weeks after inoculation, when symptoms of infection were still not observed, decreased levels of blue and green fluorescence and increased far-red fluorescence were observed in leaves of the inoculated plants. At 4 and 5 weeks after inoculation, when inoculated plants displayed symptoms of infection by O. cumana, differences in fluorescence between inoculated plants and the controls were the same and statistically supported. These results are consistent with an increase in total chlorophyll content of sunflower plants infected by O. cumana, and a decrease in the accumulation of secondary metabolites, both related to the need of higher photosynthetic activity to supply the parasite with photosynthate. Biochemical mechanisms underlying alterations in photosynthesis must be further investigated. The results obtained showed that multicolour fluorescence imaging can be used to detect fluorescence differences in inoculated sunflower as early as 3 weeks after inoculation. Therefore, this technique can be used as a diagnostic tool for early detection of genotypes of sunflower which are susceptible or resistant to O. cumana.Financial support from the Spanish Ministry of Education and Science (AGL2010-17909), Junta de Andalucía (P12-AGR370 and P12-AGR1281) and Spanish National Research Council (20134R060).Peer Reviewe

IAA : Información y actualidad astronómica (22)

Sumario : Estrellas binarias: un matrimonio muy ventajoso.-- Mujeres y ciencia: rompiendo techos.-- La estrella más masiva.-- DECONSTRUCCIÓN Y otros ENSAYOS : Criterios termodinámicos en la evolución de agujeros negros.-- ACTUALIDAD.-- ENTRE BASTIDORES.-- CIENCIA: PILARES E INCERTIDUMBRES. Núcleos de galaxias activas .-- HISTORIAS DE ASTRONOMÍA: “Serendipia” cósmica.-- El increíble y asombroso viaje de Fotón. II Parte.-- ACTIVIDADES IAA.Esta revista se publica con la ayuda de la Acción Complementaria CCT005-06-00178 del Programa Nacional de Fomento de la Cultura Científica y Tecnológica.N

Plant biology popularisation, a challenging task: Arabidopsis versus the James Webb images

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, Portugal.Doing popular science in plant biology is not an easy task, it competes with other scientific disciplines with an enormous appeal. You show your little Arabidopsis plant and you have an astronomer next to you with pictures from the James Webb telescopes. It is a challenge that has to be tackled with imagination and knowing the very diverse formats in popularisation, the traditional and the most innovative ones: films, TV or radio programmes, talks, workshops, books, printed or digital articles, scientific monologues such as the TED talks (1) or those of the Famelab competition, small musicals, tastings of vegetable products, podcasts, blogs (2), social networks. There are also large dissemination events at local (3) or European level, such as the European Researchers' Night, the Fascination of Plants Day (4), or different International Days. Organizing events in unusual places such as bars or sport places, encourages attendance. It is also very effective to seek interdisciplinarity, even with areas that are far away from each other as science and music or visual arts. It is also necessary to reach groups traditionally forgotten by popularisation: people with functional diversity, the elderly, people at risk of social exclusion and traditionally marginalised groups, without forgetting the general public and schools at all levels to attract vocations. Collaboration with local authorities is also important. In Granada we have the “Mesa de la Ciencia” coordinated by the City Council and with the participation of academic, cultural and business entities. One of its tasks is to disseminate science and knowledge in the city. This helps to integrate science popularisation in the cultural life of Granada. From my own experience this talk will focus on different formats and venues to put the plants on centre stage and combat plant blindness. It is essential to stop seeing plants only as immobile, mute, blind living beings. If I disseminate my research in plants stress, I speak first about plant sensing of their environment and communication with other plants or between its different organs. It also attracts a lot of attention to show positive examples of stress in plants and crops, such as in wines or ornamental plants. It also works to recall historical examples of the impact of plant stress, such as the Irish famine or the Tulipomania in the Netherlands. Linking scientific facts with everyday experiences or with historical events, is an effective way to connect with the public

Científicas del área agroalimentaria. La EEZ-CSIC como ejemplo

Comunicación oral presentada en: XI Jornada de la Asociación de Mujeres Investigadoras y tecnólogas AMIT. EEZ-CSIC, Granada; 4 Marzo (2022

Estudios "in vitro" e "in vivo" del mecanismo bioquímico de acción de herbicidas carbamicos sobre la actividad fotosintética

Tesis Universidad de Granada. Facultad de Ciencias. Leída el 6 de julio de 198

Copper and photosystem II: A controversial relationship

Copper is an essential micronutrient for higher plants and algae and has a direct impact on photosynthesis. It is a constituent of the primary electron donor in photosystem I, the Cu-protein plastocyanin. Many authors have also described Cu as a constituent of photosystem II (PSII). However, high Cu concentrations inhibit the photosynthetic electron transport, especially in PSII. In addition, both Cu deficiency and Cu toxicity interfere with pigment and lipid biosynthesis and, consequently, with chloroplast ultrastructure thus negatively influencing the photosynthetic efficiency.Ministerio de Educación y Ciencia (Spain)Peer reviewe

Health status of oilseed rape plants grown under potential future climatic conditions assessed by invasive and non-invasive techniques

Environmental conditions affect many plant traits such as biochemistry, physiology, morphology, and even their distribution around the world. Human activities have increased greenhouse gas emissions, which will promote a global rise in temperatures. The impact of climate change on natural vegetation and crops is difficult to predict, making it necessary to conduct experiments that mimic potential future climate conditions. Here, oilseed rape has been grown under environmental conditions that reproduce severe and intermediate climate change, setting the current climatic conditions as a control, with the main objective of evaluating the impact of climate change on the health status of this plant of agronomic interest. For such a purpose, two approaches (invasive and non-invasive) have been applied. Invasive quantitative measurements are based on the absorbance of biochemical compounds. Non-invasive methods such as thermal, multicolor fluorescence, and hyperspectral reflectance imaging sensors rely on the spectral properties of the plants. The results revealed that climate change induced lipid peroxidation, as well as alterations in pigment composition, transpiration, photosynthesis, and secondary plant metabolism. Those changes were more drastic the more severe the climatic condition imposed. Novel vegetation indices obtained from hyperspectral reflectance and specifically tailored to detect stress in brassicas correlated with physiological traits such as lipid peroxidation and secondary plant metabolism.This work was supported by grant number RTI2018-094652-B-I00 funded by Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación: MCIN/AEI/10.13039/501100011033, and by “European Regional Development Fund, ERDF: A way of making Europe”. The free open access publication was partially funded by Consejo Superior de Investigaciones Científicas (CSIC) through the Unidad de Recursos de Información Científica para la Investigación (URICI)

Assessment of black rot in oilseed rape grown under climate change conditions using biochemical methods and computer vision

Global warming is a challenge for plants and pathogens, involving profound changes in the physiology of both contenders to adapt to the new environmental conditions and to succeed in their interaction. Studies have been conducted on the behavior of oilseed rape plants and two races (1 and 4) of the bacterium Xanthomonas campestris pv. campestris (Xcc) and their interaction to anticipate our response in the possible future climate. Symptoms caused by both races of Xcc were very similar to each other under any climatic condition assayed, although the bacterial count from infected leaves differed for each race. Climate change caused an earlier onset of Xcc symptoms by at least 3 days, linked to oxidative stress and a change in pigment composition. Xcc infection aggravated the leaf senescence already induced by climate change. To identify Xcc-infected plants early under any climatic condition, four classifying algorithms were trained with parameters obtained from the images of green fluorescence, two vegetation indices and thermography recorded on Xcc-symptomless leaves. Classification accuracies were above 0.85 out of 1.0 in all cases, with k-nearest neighbor analysis and support vector machines performing best under the tested climatic conditions.This work was supported by grant number RTI2018-094652-B-I00, funded by Ministerio de Ciencia e Innovación and Agencia Estatal de Investigación: MCIN/AEI/10.13039/501100011033/, and by “European Regional Development Fund, ERDF: A way of making Europe”; and by grant Proyecto Intramural 202340E012 funded by Consejo Superior de Investigaciones Científicas (CSIC

Thermal Imaging for Plant Stress Detection and Phenotyping

© 2020 by the authors.In the last few years, large efforts have been made to develop new methods to optimize stress detection in crop fields. Thus, plant phenotyping based on imaging techniques has become an essential tool in agriculture. In particular, leaf temperature is a valuable indicator of the physiological status of plants, responding to both biotic and abiotic stressors. Often combined with other imaging sensors and data-mining techniques, thermography is crucial in the implementation of a more automatized, precise and sustainable agriculture. However, thermal data need some corrections related to the environmental and measuring conditions in order to achieve a correct interpretation of the data. This review focuses on the state of the art of thermography applied to the detection of biotic stress. The work will also revise the most important abiotic stress factors affecting the measurements as well as practical issues that need to be considered in order to implement this technique, particularly at the field scale.This research was funded by Junta de Andalucía, grant number P12-AGR-0370, and Ministerio de Ciencia, Innovación y Universidades (MCIU) by Agencia Estatal de Investigación (AEI) and European Regional Development Fund (ERDF), grant number RTI2018-094652-B-I00.Peer reviewe