Combined genomics to discover genes associated with tolerance to soil carbonate.

Carbonate-rich soils limit plant performance and crop production. Previously, local adaptation to carbonated soils was detected in wild Arabidopsis thaliana accessions, allowing the selection of two demes with contrasting phenotypes: A1 (carbonate tolerant, c+) and T6 (carbonate sensitive, c-). Here, A1(c+) and T6(c - ) seedlings were grown hydroponically under control (pH 5.9) and bicarbonate conditions (10 mM NaHCO3 , pH 8.3) to obtain ionomic profiles and conduct transcriptomic analysis. In parallel, A1(c+) and T6(c - ) parental lines and their progeny were cultivated on carbonated soil to evaluate fitness and segregation patterns. To understand the genetic architecture beyond the contrasted phenotypes, a bulk segregant analysis sequencing (BSA-Seq) was performed. Transcriptomics revealed 208 root and 2503 leaf differentially expressed genes in A1(c+) versus T6(c - ) comparison under bicarbonate stress, mainly involved in iron, nitrogen and carbon metabolism, hormones and glycosylates biosynthesis. Based on A1(c+) and T6(c - ) genome contrasts and BSA-Seq analysis, 69 genes were associated with carbonate tolerance. Comparative analysis of genomics and transcriptomics discovered a final set of 18 genes involved in bicarbonate stress responses that may have relevant roles in soil carbonate tolerance.

A genome-wide association study identifies novel players in Na and Fe homeostasis in Arabidopsis thaliana under alkaline-salinity stress.

In nature, multiple stress factors occur simultaneously. The screening of natural diversity panels and subsequent Genome-Wide Association Studies (GWAS) is a powerful approach to identify genetic components of various stress responses. Here, the nutritional status variation of a set of 270 natural accessions of Arabidopsis thaliana grown on a natural saline-carbonated soil is evaluated. We report significant natural variation on leaf Na (LNa) and Fe (LFe) concentrations in the studied accessions. Allelic variation in the NINJA and YUC8 genes is associated with LNa diversity, and variation in the ALA3 is associated with LFe diversity. The allelic variation detected in these three genes leads to changes in their mRNA expression and correlates with plant differential growth performance when plants are exposed to alkaline salinity treatment under hydroponic conditions. We propose that YUC8 and NINJA expression patters regulate auxin and jasmonic signaling pathways affecting plant tolerance to alkaline salinity. Finally, we describe an impairment in growth and leaf Fe acquisition associated with differences in root expression of ALA3, encoding a phospholipid translocase active in plasma membrane and the trans Golgi network which directly interacts with proteins essential for the trafficking of PIN auxin transporters, reinforcing the role of phytohormonal processes in regulating ion homeostasis under alkaline salinity.

Genome-Wide Association Study Reveals Key Genes for Differential Lead Accumulation and Tolerance in Natural Arabidopsis thaliana Accessions.

Soil contamination by lead (Pb) has become one of the major ecological threats to the environment. Understanding the mechanisms of Pb transport and deposition in plants is of great importance to achieve a global Pb reduction. We exposed a collection of 360 Arabidopsis thaliana natural accessions to a Pb-polluted soil. Germination rates, growth, and leaf Pb concentrations showed extensive variation among accessions. These phenotypic data were subjected to genome wide association studies (GWAs) and we found a significant association on chromosome 1 for low leaf Pb accumulation. Genes associated with significant SNP markers were evaluated and we selected EXTENSIN18 (EXT18) and TLC (TRAM-LAG1-CLN8) as candidates for having a role in Pb homeostasis. Six Pb-tolerant accessions, three of them exhibiting low leaf Pb content, and three of them with high leaf Pb content; two Pb-sensitive accessions; two knockout T-DNA lines of GWAs candidate genes (ext18, tlc); and Col-0 were screened under control and high-Pb conditions. The relative expression of EXT18, TLC, and other genes described for being involved in Pb tolerance was also evaluated. Analysis of Darwinian fitness, root and leaf ionome, and TEM images revealed that Pb-tolerant accessions employ two opposing strategies: (1) low translocation of Pb and its accumulation into root cell walls and vacuoles, or (2) high translocation of Pb and its efflux to inactive organelles or intracellular spaces. Plants using the first strategy exhibited higher expression of EXT18 and HMA3, thicker root cell walls and Pb vacuolar sequestration, suggesting that these genes may contribute to the deposition of Pb in the roots. On the other hand, plants translocating high amounts of Pb showed upregulation of TLC and ABC transporters, indicating that these plants were able to properly efflux Pb in the aerial tissues. We conclude that EXT18 and TLC upregulation enhances Pb tolerance promoting its sequestration: EXT18 favors the thickening of the cell walls improving Pb accumulation in roots and decreasing its toxicity, while TLC facilitates the formation of dictyosome vesicles and the Pb encapsulation in leaves. These findings are relevant for the design of phytoremediation strategies and environment restoration.

Severe knee injuries among karate athletes ranking towards the Tokyo Olympic Games: a retrospective study.

BACKGROUND: Injury prevention strategies should be built upon data about the more frequent injuries in each specific sport. Therefore, this study aimed to describe the lifetime prevalence and characteristics of severe knee injuries among world-class karatekas. METHODS: A retrospective study based on a face-to-face survey was conducted. Participants were athletes who competed in World Karate Senior Championships in Madrid 2018, which was a tournament with the highest value to rank athletes to the Tokyo Olympic Games. A questionnaire was used to collect retrospective information on the prevalence and characteristics of severe knee injuries that occurred along elite karatekas sport careers. Odds Ratio (OR) were calculated to identify the association of sex and karate modality (kata / kumite) with severe knee injury risk. RESULTS: Out of the 293 athletes surveyed (23.4±4.0 years; 137 female), 71 (24.2%) had suffered a serious knee injury at some point of their careers, without a statistically significant difference between male and female athletes. There was no difference between the percentage of injuries that took place during training (54.9%) or during competition (45.1%) both in male and female athletes. Kumite athletes suffered more knee injuries during competition than training. The most common injury mechanism for both genders was a pivoting or dodging movement (36.4% in males and 39.5% in females). CONCLUSIONS: The information presented in this study about the prevalence and characteristics (mechanism, anatomical location, moment, time off) of the severe knee injuries in elite karatekas could be useful to design prevention programs to be implemented among karate athletes.

Identifying the Specific Root Microbiome of the Hyperaccumulator Noccaea brachypetala Growing in Non-metalliferous Soils.

Noccaea brachypetala is a close relative of Noccaea caerulescens, a model plant species used in metal hyperaccumulation studies. In a previous survey in the Catalan Pyrenees, we found two occidental and two oriental N. brachypetala populations growing on non-metalliferous soils, with accumulated high concentrations of Cd and Zn. Our hypothesis was that the microbiome companion of the plant roots may influence the ability of these plants to absorb metals. We performed high-throughput sequencing of the bacterial and fungal communities in the rhizosphere soil and rhizoplane fractions. The rhizobiomes and shoot ionomes of N. brachypetala plants were analyzed along with those from other non-hyperaccumulator Brassicaceae species found at the same sampling locations. The analyses revealed that microbiome richness and relative abundance tended to increase in N. brachypetala plants compared to non-hyperaccumulator species, regardless of plant location. We confirmed that the root compartment is a key factor in describing the community composition linked to the cohabiting Brassicaceae species, and the rhizoplane fraction contained the specific and rare taxa associated with each species. N. brachypetala plants harbored a similar relative abundance of fungi compared to the other plant hosts, but there was a notable reduction in some specific taxa. Additionally, we observed an enrichment in the hyperaccumulator rhizoplane of previously described metal-tolerant bacteria and bacteria involved in nitrogen cycling. The bacteria involved in the nitrogen cycle could contribute indirectly to the hyperaccumulator phenotype by improving soil quality and fertility. Our results indicate that N. brachypetala captures a particular prokaryotic community from the soil. This particular prokaryotic community may benefit the extraction of metal ions and/or improve plant nutrition. Our research identified satellite groups associated with the root niche of a hyperaccumulator plant that may assist in improving biological strategies in heavy metal remediation.

Transcriptomics Reveals Fast Changes in Salicylate and Jasmonate Signaling Pathways in Shoots of Carbonate-Tolerant Arabidopsis thaliana under Bicarbonate Exposure.

High bicarbonate concentrations of calcareous soils with high pH can affect crop performance due to different constraints. Among these, Fe deficiency has mostly been studied. The ability to mobilize sparingly soluble Fe is a key factor for tolerance. Here, a comparative transcriptomic analysis was performed with two naturally selected Arabidopsis thaliana demes, the carbonate-tolerant A1(c+) and the sensitive T6(c-). Analyses of plants exposed to either pH stress alone (pH 5.9 vs. pH 8.3) or to alkalinity caused by 10 mM NaHCO3 (pH 8.3) confirmed better growth and nutrient homeostasis of A1(c+) under alkaline conditions. RNA-sequencing (RNA-seq) revealed that bicarbonate quickly (3 h) induced Fe deficiency-related genes in T6(c-) leaves. Contrastingly, in A1(c+), initial changes concerned receptor-like proteins (RLP), jasmonate (JA) and salicylate (SA) pathways, methionine-derived glucosinolates (GS), sulfur starvation, starch degradation, and cell cycle. Our results suggest that leaves of carbonate-tolerant plants do not sense iron deficiency as fast as sensitive ones. This is in line with a more efficient Fe translocation to aerial parts. In A1(c+) leaves, the activation of other genes related to stress perception, signal transduction, GS, sulfur acquisition, and cell cycle precedes the induction of iron homeostasis mechanisms yielding an efficient response to bicarbonate stress.

Soil carbonate drives local adaptation in Arabidopsis thaliana.

High soil carbonate limits crop performance especially in semiarid or arid climates. To understand how plants adapt to such soils, we explored natural variation in tolerance to soil carbonate in small local populations (demes) of Arabidopsis thaliana growing on soils differing in carbonate content. Reciprocal field-based transplants on soils with elevated carbonate (+C) and without carbonate (-C) over several years revealed that demes native to (+C) soils showed higher fitness than those native to (-C) soils when both were grown together on carbonate-rich soil. This supports the role of soil carbonate as a driving factor for local adaptation. Analyses of contrasting demes revealed key mechanisms associated with these fitness differences. Under controlled conditions, plants from the tolerant deme A1(+C) native to (+C) soil were more resistant to both elevated carbonate and iron deficiency than plants from the sensitive T6(-C) deme native to (-C) soil. Resistance of A1(+C) to elevated carbonate was associated with higher root extrusion of both protons and coumarin-type phenolics. Tolerant A1(+C) also had better Ca-exclusion than sensitive T6(-C) . We conclude that Arabidopsis demes are locally adapted in their native habitat to soils with moderately elevated carbonate. This adaptation is associated with both enhanced iron acquisition and calcium exclusion.

Cadmium hampers salt tolerance of Sesuvium portulacastrum.

It is well known that salinity reduces cadmium toxicity in halophytes. However, the possible interference of Cd with the mechanisms of salt tolerance is poorly explored. The aim of this study was to see whether Cd affects salt tolerance mechanisms in the halophyte Sesuvium portulacastrum. S. portulacastrum plants obtained from cuttings were grown in hydroponics for 3 weeks and then exposed to low (0.09 mM) or moderate (200 mM) NaCl concentrations, alone or in combination with 25 µM CdCl2. Microscopy observation revealed two strategies of salt tolerance: euhalophytism and secretion of salt by bladder cells. Cadmium exposure hardly influenced the total leaf Na+ concentrations. However, Cd supply delayed the salt-induced upregulation of AHA1 (plasma membrane H+-ATPase 1) and SOS1 (plasma membrane Na+ transporter "Salt Overly Sensitive 1"), genes that are essential for salt tolerance. Moreover, Cd induced the activation of BADH, coding for betaine aldehyde dehydrogenase, indicating enhanced osmotic stress due to Cd. Sodium-green fluorescence in protoplasts from plants grown with low or high NaCl, alone or in combination with Cd, revealed higher Na+ concentrations in the cytoplasm of Cd-exposed plants. Taken together the results indicate interference of Cd with salt tolerance mechanisms in S. portulacastrum. This may have consequences for the efficient use of halophytes in phytoremediation of Cd-contaminated saline soils.

[EVALUATION OF THE EFFICIENCY OF CLEANING THE AIR BETWEEN TWO METHODS OF MAKING IN PATIENTS WITH AEROSOL CHRONIC OBSTRUCTIVE PULMONARY DISEASE]. / Evaluación de la eficacia en la limpieza de la vía aérea entre dos métodos de toma de aerosolterapia en pacientes con enfermedad pulmonar obstructiva croníca.

INTRODUCTION: Chronic Obstructive Pulmonary Disease (COPD) is a condition which requires, among others, the administration of bronchodilators and anti-inflammatory drugs to control the disease. They help to keep the airways clear and prevent the buildup of fluid and mucus. Inhalation is the most widely used form of administrating the medication because of its local and rapid action which normally is done by aerosol therapy. The objective of this study is to evaluate the effectiveness of two aerosol methods in clearing the airways of COPD patients, admitted with an exacerbation due to their disease. It also aims to evaluate its effects on the length of stay, oxygen saturation, dyspnea, autonomy and complications. METHODS: Randomized clinical trial. Traditional method (control group) and positive expiratory vibrating device (intervention group): two ways to deliver aerosol were compared. The following outcome variables were considered: length of stay, days of fever, oxygen saturation, need for NIV or VM, the basic activities of daily living index autonomy (Barthel), dyspnea (Borg scale) and peak-flow. RESULTS: 39 patients were included. Regarding hospital stay, patients in the intervention group spend an average of one day less in hospital. Also in this group there were fewer readmissions. No statistically significant differences were found in the remaining variables. CONCLUSIONS: The inhalation treatment with a vibrating device with positive exhalation, appears to reduce the length of stay and prevent readmissions. It is important to continue research on non-pharmacological interventions as to achieve the prevention of relapses.

Evaluación de la eficacia en la limpieza de la vía aérea entre dos métodos de toma de aerosolterapia en pacientes con enfermedad pulmonar obstructiva crónica / Evaluation of the efficiency of cleaning the air between two methods of making in patients with aerosol chronic obstructive pulmonary disease

Introducción. La enfermedad pulmonar obstructiva crónica (EPOC) es un trastorno que requiere la administración de medicación broncodilatadora y antiinflamatoria, entre otras, como uno de los cuidados de la enfermedad. Ayudan a mantener la limpieza de la vía aérea y a evitar recaídas por el acúmulo de secreciones. La vía inhalatoria, por su acción local y rápida, es la más usada para la aplicación de estos fármacos, que habitualmente se realiza en forma de aerosolterapia. El objetivo de este estudio es evaluar la eficacia en la limpieza de la vía aérea entre dos métodos de administración de aerosolterapia en pacientes con EPOC ingresados por una exacerbación de su enfermedad. También se pretende evaluar su efecto sobre los días de estancia, saturación de oxígeno, grado de disnea, autonomía y complicaciones. Método. Ensayo clínico aleatorizado. Se compararon dos formas de administrar aerosolterapia: método tradicional (grupo control) y dispositivo vibratorio con espiración positiva (grupo intervención). Se consideraron las siguientes variables resultado: días de estancia, días con fiebre, saturación de oxígeno, necesidad de VMNI o VM, las actividades básicas de la vida diaria, grado de autonomía (Barthel), grado de disnea (Escala de Borg) y pico flujo. Resultados. Se incluyeron 39 pacientes. En cuanto a los días de ingreso, los pacientes del grupo intervención presentaban de media un día menos de ingreso. También en este grupo hubo menos reingresos. No se encontraron diferencias estadísticamente significativas en el resto de las variables. Conclusiones. El tratamiento inhalatorio con un dispositivo vibratorio con espiración positiva parece reducir los días de estancia y prevenir los reingresos. Es importante seguir investigando sobre intervenciones no farmacológicas que consigan prevenir sus recaídas (AU)

Introduction. Chronic Obstructive Pulmonary Disease (COPD) is a condition which requires, among others, the administration of bronchodilators and anti-inflammatory drugs to control the disease. They help to keep the airways clear and prevent the buildup of fluid and mucus. Inhalation is the most widely used form of administrating the medication because of its local and rapid action which normally is done by aerosol therapy. The objective of this study is to evaluate the effectiveness of two aerosol methods in clearing the airways of COPD patients, admitted with an exacerbation due to their disease. It also aims to evaluate its effects on the length of stay, oxygen saturation, dyspnea, autonomy and complications. Methods. Randomized clinical trial. Traditional method (control group) and positive expiratory vibrating device (intervention group): two ways to deliver aerosol were compared. The following outcome variables were considered: length of stay, days of fever, oxygen saturation, need for NIV or VM, the basic activities of daily living index autonomy (Barthel), dyspnea (Borg scale) and peak-flow. Results. 39 patients were included. Regarding hospital stay, patients in the intervention group spend an average of one day less in hospital. Also in this group there were fewer readmissions. No statistically significant differences were found in the remaining variables. Conclusions. The inhalation treatment with a vibrating device with positive exhalation, appears to reduce the length of stay and prevent readmissions. It is important to continue research on non-pharmacological interventions as to achieve the prevention of relapses (AU)