Novel culture chamber to evaluate in vitro plant-microbe volatile interactions: effects of Trichoderma harzianum volatiles on wheat plantlets

.The field of plant-microbe interactions mediated by Biogenic Volatile Organic Compounds (BVOCs) still faces several limitations due to the lack of reliable equipment. We present a novel device designed to evaluate in vitro plant-microbe volatile interactions, the plant-microbe VOC Chamber. It was tested by evaluating the effects exerted on wheat development by volatiles from three Trichoderma harzianum strains, a wild type and two genetically modified strains; one expressing the tri5 gene, which leads to the synthesis and emission of the volatile trichodiene, and the other by silencing the erg1 gene, impairing ergosterol production. The wild type and the erg1-silenced strain enhanced fresh weight and length of the aerial part, but reduced root dry weight. Interestingly, no differences were found between them. Conversely, the tri5-transformant strain reduced root and aerial growth compared to the control and the other strains. No differences were observed regarding chlorophyll fluorescence quantum yield and leaf chlorophyll content, suggesting that the released BVOCs do not interfere with photosynthesis. The plant-microbe VOC Chamber proved to be a simple and reliable method to evaluate the in vitro effects of microbial BVOCs on plant development, perfect for the screening of microorganisms with interesting volatile traits. Availability of data and materials The data that support the findings of this study are available from the corresponding authors (Antonio Encina and Samuel Álvarez-García) upon reasonable request. All microbiological strains used in this study will be made available to researchers upon reasonable request. VOC Chambers will be made available to researchers upon reasonable request, unless commercial agreements reached with third parties regarding the patent exploitation prohibit it (in which case the VOC Chambers should be available in the market).S

Experiencias fascinantes en la docencia de la Biología de las Plantas

[ES] “Savia Sabia” es un grupo de innovación docente integrado por docentes del Área de Fisiología Vegetal de la Universidad de León, dedicado a crear entornos educativos motivadores para la enseñanza de la Biología de las Plantas. Entre sus objetivos está la puesta en marcha de recursos de enseñanza-aprendizaje basados en la fascinación por las plantas. Desde que comenzó como grupo en 2014, su filosofía ha sido motivar el interés de los alumnos de los Grados de Biotecnología y Biología por el mundo de la Biología de las Plantas a través de actividades en las que participan directamente y desarrollan diferentes habilidades. Muchos de estos recursos han surgido a partir de la participación del grupo en el Día internacional de Fascinación por las Plantas, a través de la puesta en marcha del Taller denominado “Experimentos fascinantes con plantas”. Fruto de esta iniciativa surgió la publicación del libro “Experimentos fascinantes con plantas” y de vídeos en YouTube, que facilitaran la integración de los experimentos en la docencia propia de diversos niveles educativos. Otros proyectos han consistido en la elaboración del programa de radio “Hablando en verde”, la obra de teatro “Historia de la Biotecnología Vegetal”, la edición de mini-vídeos “Yo me quedo en casa estudiando Fisiología Vegetal”, un taller de escritura científica, así como el desarrollo de diversas experiencias de creatividad y gamificación, como “el desafío” y “retos de cine”, y más recientemente la creación de PLANTA, un juego de cartas didáctico. Todas estas iniciativas han sido valoradas muy positivamente por los estudiantes, han sido difundidas a través de ponencias y comunicaciones en congresos y otras publicaciones, y son transferibles a otras materias universitarias

Planta: un proyecto de aprendizaje basado en juegos en Fisiología Vegetal

[ES] Planta es un juego de cartas pensado como herramienta docente para introducir o repasar conceptos científicotécnicos relacionados con las plantas y su cultivo. A través de este juego se pretende alcanzar el objetivo descrito de manera sencilla, rigurosa, en un ambiente distendido y para distintos niveles de la educación. El argumento del juego es asumir el reto de hacer crecer, mantener y cosechar un cultivo afectado por diversos factores de estrés provocados por los jugadores adversarios. Durante el juego se tratan aspectos básicos del cultivo de las plantas, su fisiología, los aspectos adversos que condicionan su productividad, y los recursos disponibles para remediarlos. El primer paso del proyecto fue crear el juego en sí: mediante un proceso de ensayo y error se alcanzó una versión básica, con diseños de cartas originales, que fue probada entre los propios autores. Ello permitió afinar las reglas del juego y ajustarlas para que el desarrollo de una partida no durara más de treinta minutos. Posteriormente, se encargó una impresión profesional con la cual se realizaron diferentes sesiones con alumnos voluntarios universitarios y de bachillerato. Tras las sesiones, su opinión se recogió en una encuesta. La valoración general del juego fue muy positiva. En la actualidad el juego está en fase de protección de la propiedad intelectual. Por último, está planteada una ampliación del juego (versión avanzada) consistente en la incorporación de cartas con preguntas (de necesaria respuesta para el progreso del jugador en el juego) de conceptos clave en las diferentes asignaturas del área de Fisiología Vegetal en las que se aplique esta herramienta. En las encuestas, los alumnos expresaron de manera clara que les gustaría que el plan de ampliación se llevara a cabo y se aplicara como herramienta docente en las asignaturas del grado

Elucidating compositional factors of maize cell walls contributing to stalk strength and lodging resistance

Lodging is one of the causes of maize (Zea mays L.) production losses worldwide and, at least, the resistance to stalk lodging has been positively correlated with stalk strength. In order to elucidate the putative relationship between cell wall, stalk strength and lodging resistance, twelve maize inbreds varying in rind penetration strength and lodging resistance were characterized for cell wall composition and structure. Stepwise multiple regression indicates that H lignin subunits confer a greater rind penetration strength. Besides, the predictive model for lodging showed that a high ferulic acid content increases the resistance to lodging, whereas those of diferulates decrease it. These outcomes highlight that the strength and lodging susceptibility of maize stems may be conditioned by structural features of cell wall rather than by the net amount of cellulose, hemicelluloses and lignin. The results presented here provide biotechnological targets in breeding programs aimed at improving lodging in maize.This work was funded by Projects AGL2014−58126-R and RTC-2016−5816-2 from the Spanish Ministry of Science, Innovation and Universities. This work was also supported by the CERCA Program and the SGR program (SGR-710) from the Generalitat de Catalunya. We acknowledge financial support from the Spanish Ministry of Economy and Competitiveness, through the “Severo Ochoa Program for Centres of Excellence in R&D” 2016–2019 (SEV‐2015‐0533)”. Alba Manga-Robles’s contract was granted by the Junta de Castilla y León and the Fondo Social Europeo through “Sistema Nacional de Garantía Juvenil” Program, Universidad de León and Junta de Castilla y León predoctoral Programs. Rogelio Santiago acknowledges a postdoctoral contract “Ramón y Cajal” financed by the Ministry of Economy and Competitiveness of Spain (RYC-2012-10603).Peer reviewe

Pioneras en Ciencia

Serie: Talleres del "Día internacional de la mujer y la niña en la ciencia

Diverging cell wall strategies for drought adaptation in two maize inbreds with contrasting lodging resistance

The plant cell wall is a plastic structure of variable composition that constitutes the first line of defence against environmental challenges. Lodging and drought are two stressful conditions that severely impact maize yield. In a previous work, we characterised the cell walls of two maize inbreds, EA2024 (susceptible) and B73 (resistant) to stalk lodging. Here, we show that drought induces distinct phenotypical, physiological, cell wall, and transcriptional changes in the two inbreds, with B73 exhibiting lower tolerance to this stress than EA2024. In control conditions, EA2024 stalks had higher levels of cellulose, uronic acids and p‐coumarate than B73. However, upon drought EA2024 displayed increased levels of arabinose‐enriched polymers, such as pectin‐arabinans and arabinogalactan proteins, and a decreased lignin content. By contrast, B73 displayed a deeper rearrangement of cell walls upon drought, including modifications in lignin composition (increased S subunits and S/G ratio; decreased H subunits) and an increase of uronic acids. Drought induced more substantial changes in gene expression in B73 compared to EA2024, particularly in cell wall‐related genes, that were modulated in an inbred‐specific manner. Transcription factor enrichment assays unveiled inbred‐specific regulatory networks coordinating cell wall genes expression. Altogether, these findings reveal that B73 and EA2024 inbreds, with opposite stalk‐lodging phenotypes, undertake different cell wall modification strategies in response to drought. We propose that the specific cell wall composition conferring lodging resistance to B73, compromises its cell wall plasticity, and renders this inbred more susceptible to drought.This work was supported by the Grants AGL2014-58126-R; RTC-2016-5816-2 and PID2022-142786NB-I00 funded by MCIN/AEI/10.13039/501100011033 and ERDF “A way to make Europe” and received financial support from the CONSOLIDER-INGENIO programme (CSD2007-00036) from the Spanish Ministerio de Ciencia e Innovación. S.C. was financed with a PhD contract (PRE2019-089329) funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future”, and by SEV-2015-0533-19-1 and CEX2019-000902-S funded by MCIN/AEI/10.13039/501100011033. A.M.-R. was financed with a PhD contract from the Consejería de Educación de Castilla y León and the Fondo Social Europeo (ORDEN EDU/601/2020, July 7th). This work was also supported by the SGR programmes (2017SGR710 and 2021-SGR-01131) from the Secretaria d'Universitats i Recerca del Departament d'Empresa i Coneixement de la Generalitat de Catalunya and by the CERCA Programme/Generalitat de Catalunya. This work was financially supported by RYC2021-033414-l to R.U funded by MCIN/AEI/10.13039/501100011033 by the “European Union Next Generation EU/PRTR”. Finally, we acknowledge financial support from the Grants SEV-2015-0533-19-1 and CEX2019-000902-S funded by MCIN/AEI/10.13039/501100011033.info:eu-repo/semantics/publishedVersio

Elucidating compositional factors of maize cell walls contributing to stalk strength and lodging resistance

Lodging is one of the causes of maize (Zea mays L.) production losses worldwide and, at least, the resistance to stalk lodging has been positively correlated with stalk strength. In order to elucidate the putative relationship between cell wall, stalk strength and lodging resistance, twelve maize inbreds varying in rind penetration strength and lodging resistance were characterized for cell wall composition and structure. Stepwise multiple regression indicates that H lignin subunits confer a greater rind penetration strength. Besides, the predictive model for lodging showed that a high ferulic acid content increases the resistance to lodging, whereas those of diferulates decrease it. These outcomes highlight that the strength and lodging susceptibility of maize stems may be conditioned by structural features of cell wall rather than by the net amount of cellulose, hemicelluloses and lignin. The results presented here provide biotechnological targets in breeding programs aimed at improving lodging in maize.info:eu-repo/semantics/acceptedVersio

Diverging cell wall strategies for drought adaptation in two maize inbreds with contrasting lodging resistance

The plant cell wall is a plastic structure of variable composition that constitutes the first line of defence against environmental challenges. Lodging and drought are two stressful conditions that severely impact maize yield. In a previous work, we characterised the cell walls of two maize inbreds, EA2024 (susceptible) and B73 (resistant) to stalk lodging. Here, we show that drought induces distinct phenotypical, physiological, cell wall, and transcriptional changes in the two inbreds, with B73 exhibiting lower tolerance to this stress than EA2024. In control conditions, EA2024 stalks had higher levels of cellulose, uronic acids and p‐coumarate than B73. However, upon drought EA2024 displayed increased levels of arabinose‐enriched polymers, such as pectin‐arabinans and arabinogalactan proteins, and a decreased lignin content. By contrast, B73 displayed a deeper rearrangement of cell walls upon drought, including modifications in lignin composition (increased S subunits and S/G ratio; decreased H subunits) and an increase of uronic acids. Drought induced more substantial changes in gene expression in B73 compared to EA2024, particularly in cell wall‐related genes, that were modulated in an inbred‐specific manner. Transcription factor enrichment assays unveiled inbred‐specific regulatory networks coordinating cell wall genes expression. Altogether, these findings reveal that B73 and EA2024 inbreds, with opposite stalk‐lodging phenotypes, undertake different cell wall modification strategies in response to drought. We propose that the specific cell wall composition conferring lodging resistance to B73, compromises its cell wall plasticity, and renders this inbred more susceptible to drought