Nuclear protein phosphatases with Kelch-repeat domains modulate the response to brassinosteroids in Arabidopsis

Perception of the plant steroid hormone brassinolide (BL) by the membrane-associated receptor kinase BRI1 triggers the dephosphorylation and accumulation in the nucleus of the transcriptional modulators BES1 and BZR1. We identified bsu1-1D as a dominant suppressor of bri1 in A abidopsis. BSU1 encodes a nuclear-localized serine-threonine protein phosphatase with an N-terminal Kelch-repeat domain, and is preferentially expressed in elongating cells. BSU1 is able to modulate the phosphorylation state of BES1, counter acting the action of the glycogen synthase kinase-3 BIN2, and leading to inc eased steady-state levels of dephosphorylated BES1. BSU1 belongs to a small gene family; loss-of-function analyses unravel the extent of functional overlap among members of the family and confirm the role of these phosphatases in the control of cell elongation by BL. Our data indicate that BES1 is subject to antagonistic phosphorylation and dephosphorylation reactions in the nucleus, which fine-tune the amplitude of the response to BL.Fil: Mora Garcia, Santiago. Salk Institute. Plant Biology Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Howard Hughes Medical Institute; Estados UnidosFil: Vert, Gregory. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Yin, Yanhai. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Caño Delgado, Ana. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Cheong, Hyeonsook. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Chory, Joanne. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados Unido

The physiology of plant responses to drought

Altres ajuts: CERCA Programme/Generalitat de Catalunya Fundación Tatiana Pérez de Guzmán el BuenoDrought alone causes more annual loss in crop yield than all pathogens combined. To adapt to moisture gradients in soil, plants alter their physiology, modify root growth and architecture, and close stomata on their aboveground segments. These tissue-specific responses modify the flux of cellular signals, resulting in early flowering or stunted growth and, often, reduced yield. Physiological and molecular analyses of the model plant Arabidopsis thaliana have identified phytohormone signaling as key for regulating the response to drought or water insufficiency. Here we discuss how engineering hormone signaling in specific cells and cellular domains can facilitate improved plant responses to drought. We explore current knowledge and future questions central to the quest to produce high-yield, drought-resistant crop

Evaluación de la posición, la integración y la resorción de los injertos de huesos empleados en el tratamiento quirúrgico de los sujetos con inestabilidad glenohumeral anteroinferior y defectos óseos glenoideos

de hueso en el hombro, ya sea en la glena, en el húmero o en ambos. La existencia de estos defectos óseos aumenta el riesgo de fracaso de las técnicas de reparación artroscópica en las que sólo se reparan partes blandas, siendo en estos casos necesario añadir un injerto de hueso. Este puede proceder bien de la coracoides del propio paciente (procedimiento de Latarjet) como de la cresta iliaca del paciente (autoinjerto) o bien ser de banco de hueso (aloinjerto). El éxito de estos procedimientos depende del correcto posicionamiento del injerto y de su integración con el hueso huésped. Por ello es fundamental, en primer lugar, describir un sistema de evaluación que sea preciso y reproducible en la evaluación del posicionamiento del injerto. Este sistema se encuentra descrito para los procedimientos de Latarjet pero no para el procedimiento de bloque óseo artroscópico. Este ha sido, por tanto, uno de los objetivos del estudio. En segundo lugar, tal y como decíamos previamente, la posición e integración de los injertos es fundamental para el éxito de los procedimientos de aporte óseo. Dado que se han descrito distintas técnicas e injertos es preciso conocer si estos logran tasas de buen posicionamiento e integración del injerto y, por tanto, son efectivos en la restauración de la superficie glenoidea a corto y medio plazo

CCD Strömgren photometry of young reddened clusters

The capabilities of CCD uvby photometry for the study of reddened young clusters are investigated. Observations of four fields in the direction of the clusters Basel 1, Berkeley 86, NGC 6704, and NGC 6756, with a total of 1665 stars measured in at least the y and b bands, produce new estimates for the clusters parameters. The results are compared to those from previously published studies in different photometric systems showing good agreement in the values of color excess and distance modulus, with the exception of NGC 6756, for which an essentially larger distance is found. Furthermore, the ages estimated for this cluster, Basel 1, and NGC 6704 are found to be higher than previously assumed, in particular for the last one. The presence of red giants as cluster members is suggested in Basel 1, NGC 6704, and NGC 6756.Consejería de Educacion y Ciencia Junta de Andalucí

Brassinosteroids en route

Brassinosteroid (BR) hormones promote root growth by controlling meristem size and cell elongation, but the mechanism of BR transport remains elusive. A new study shows that BR precursors move via intercellular pores called plasmodesmata to modulate BR cellular levels and their signaling functions

Analysis of metabolic dynamics during drought stress in Arabidopsis plants

Altres ajuts: we acknowledge support from the CERCA Programme/Generalitat de CatalunyaDrought is a major cause of agricultural losses worldwide. Climate change will intensify drought episodes threatening agricultural sustainability. Gaining insights into drought response mechanisms is vital for crop adaptation to climate emergency. To date, only few studies report comprehensive analyses of plant metabolic adaptation to drought. Here, we present a multifactorial metabolomic study of early-mid drought stages in the model plant Arabidopsis thaliana. We sampled root and shoot tissues of plants subjected to water withholding over a six-day time course, including brassinosteroids receptor mutants previously reported to show drought tolerance phenotypes. Furthermore, we sequenced the root transcriptome at basal and after 5 days drought, allowing direct correlation between metabolic and transcriptomic changes and the multi-omics integration. Significant abiotic stress signatures were already activated at basal conditions in a vascular-specific receptor overexpression (BRL3ox). These were also rapidly mobilized under drought, revealing a systemic adaptation strategy driven from inner tissues of the plant. Overall, this dataset provides a significant asset to study drought metabolic adaptation and allows its analysis from multiple perspective

BRL1 and BRL3 are novel brassinosteroid receptors that function in vascular differentiation in Arabidopsis

Plant steroid hormones, brassinosteroids (BRs), are perceived by the plasma membrane-localized leucine-rich-repeat-receptor kinase BRI1. Based on sequence similarity, we have identified three members of the BRI1 family, named BRL1, BRL2 and BRL3. BRL1 and BRL3, but not BRL2, encode functional BR receptors that bind brassinolide, the most active BR, with high affinity. In agreement, only BRL1 and BRL3 can rescue bri1 mutants when expressed under the control of the BRI1 promoter. While BRI1 is ubiquitously expressed in growing cells, the expression of BRL1 and BRL3 is restricted to non-overlapping subsets of vascular cells. Loss-of-function of brl1 causes abnormal phloem:xylem differentiation ratios and enhances the vascular defects of a weak bri1 mutant. bri1 brl1 brl3 triple mutants enhance bri1 dwarfism and also exhibit abnormal vascular differentiation. Thus, Arabidopsis contains a small number of BR receptors that have specific functions in cell growth and vascular differentiation.Fil: Caño Delgado, Ana. Salk Institute. Plant Biology Laboratory; Estados Unidos. Howard Hughes Medical Institute; Estados UnidosFil: Yin, Yanhai. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Yu, Cong. University of Michigan; Estados UnidosFil: Vafeados, Dionne. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados UnidosFil: Mora Garcia, Santiago. Howard Hughes Medical Institute; Estados Unidos. Salk Institute. Plant Biology Laboratory; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Cheng, Jin Chen. University of Michigan; Estados UnidosFil: Nam, Kyoung Hee. University of Michigan; Estados UnidosFil: Li, Jianming. University of Michigan; Estados UnidosFil: Chory, Joanne. Salk Institute. Plant Biology Laboratory; Estados Unidos. Howard Hughes Medical Institute; Estados Unido

BRAVO self-confined expression through WOX5 in the Arabidopsis root stem-cell niche

In animals and plants, stem-cell niches are local microenvironments that are tightly regulated to preserve their unique identity while communicating with adjacent cells that will give rise to specialized cell types. In the primary root of Arabidopsis thaliana, two transcription factors, BRAVO and WOX5, among others, are expressed in the stem-cell niche. Intriguingly, BRAVO, a repressor of quiescent center divisions, confines its own gene expression to the stem-cell niche, as evidenced in a bravo mutant background. Here, we propose through mathematical modeling that BRAVO confines its own expression domain to the stem-cell niche by attenuating a WOX5-dependent diffusible activator of BRAVO. This negative feedback drives WOX5 activity to be spatially restricted as well. The results show that WOX5 diffusion and sequestration by binding to BRAVO are sufficient to drive the experimentally observed confined BRAVO expression at the stem-cell niche. We propose that the attenuation of a diffusible activator can be a general mechanism acting at other stem-cell niches to spatially confine genetic activity to a small region while maintaining signaling within them and with the surrounding cells

Drought resistance by engineering plant tissue-specific responses

Altres ajuts: CERCA Programme/Generalitat de CatalunyaDrought is the primary cause of agricultural loss globally, and represents a major threat to food security. Currently, plant biotechnology stands as one of the most promising fields when it comes to developing crops that are able to produce high yields in water-limited conditions. From studies of Arabidopsis thaliana whole plants, the main response mechanisms to drought stress have been uncovered, and multiple drought resistance genes have already been engineered into crops. So far, most plants with enhanced drought resistance have displayed reduced crop yield, meaning that there is still a need to search for novel approaches that can uncouple drought resistance from plant growth. Our laboratory has recently shown that the receptors of brassinosteroid (BR) hormones use tissue-specific pathways to mediate different developmental responses during root growth. In Arabidopsis, we found that increasing BR receptors in the vascular plant tissues confers resistance to drought without penalizing growth, opening up an exceptional opportunity to investigate the mechanisms that confer drought resistance with cellular specificity in plants. In this review, we provide an overview of the most promising phenotypical drought traits that could be improved biotechnologically to obtain drought-tolerant cereals. In addition, we discuss how current genome editing technologies could help to identify and manipulate novel genes that might grant resistance to drought stress. In the upcoming years, we expect that sustainable solutions for enhancing crop production in water-limited environments will be identified through joint efforts