Assessment of the physiological performance of the invasive oriental shrimp Palaemon macrodactylus from an atypical marine population.

Since 2000, a well-established population of the invasive oriental shrimp Palaemon macrodactylus has been present in fully marine conditions in the southwestern Atlantic Ocean (~38° S). To assess the physiological performance of this atypical population restricted to fully marine conditions, we conducted a laboratory experiment in which individuals were transferred from 35 ‰S (local seawater) to 2 ‰S; 5 ‰S; 10 ‰S; 20 ‰S; 50 ‰S and 60‰ for short (6 h), medium (48 h), and long (>504 h) acclimation periods. We measured the time course response of relevant parameters in the shrimp's hemolymph; activity of Na+, K+-ATPase (NKA), and V-H+-ATPase (VHA); and muscle water content. Shrimp showed great osmoregulatory plasticity, being able to survive for long periods between 5 ‰S and 50 ‰S, whereas no individual survived after transfer to either 2 ‰S or 60 ‰S. Shrimp hyper-regulated hemolymph osmolality at 5 ‰S and 10 ‰S, hypo-regulated at 35 ‰S and 50 ‰S, and isosmoticity was close to 20 ‰S. Compared to 35 ‰S, prolonged acclimation to 5 ‰S caused a decrease in hemolymph osmolality (~34%) along with sodium and chloride concentrations (~24%); the NKA and VHA activities decreased by ~52% and ~88%, respectively, while muscle water content was tightly regulated. Our results showed that the atypical population of P. macrodactylus studied here lives in a chronic hypo-osmo-ion regulatory state and suggest that fully marine conditions contribute to its poor performance at the lower limit of salinity tolerance (<5 ‰S).

A risk assessment on Zostera chilensis, the last relict of marine angiosperms in the South-East Pacific Ocean, due to the development of the desalination industry in Chile.

Seagrasses, which are considered among the most ecologically valuable and endangered coastal ecosystems, have a narrowly limited distribution in the south-east Pacific, where Zostera chilensis is the only remaining relict. Due to water scarcity, desalination industry has grown in the last decades in the central-north coasts of Chile, which may be relevant to address in terms of potential impacts on benthic communities due to their associated high-salinity brine discharges to subtidal ecosystems. In this work, we assessed ecophysiological and cellular responses to desalination-extrapolable hypersalinity conditions on Z. chilensis. Mesocosms experiments were performed for 10 days, where plants were exposed to 3 different salinity treatments: 34 psu (control), 37 psu and 40 psu. Photosynthetic performance, H2O2 accumulation, and ascorbate content (reduced and oxidized) were measured, as well as relative gene expression of enzymes related to osmotic regulation and oxidative stress; these, at 1, 3, 6 and 10 days. Z. chilensis showed a decrease in photosynthetic parameters such as electron transport rate (ETRmax) and saturation irradiance (EkETR) under hypersalinity treatments, while non-photochemical quenching (NPQmax) presented an initial increment and a subsequent decline at 40 psu. H2O2 levels increased with hypersalinity, while ascorbate and dehydroascorbate only increased under 37 psu, although decreased along the experimental period. Increased salinities also triggered the expression of genes related to ion transport and osmolyte syntheses, but salinity-dependent up-regulated genes were mostly those related to the reactive oxygen species metabolism. The relict seagrass Z. chilensis has shown to withstand increased salinities that may be extrapolable to desalination effects in the short-term. As the latter is not fully clear in the long-term, and considering the restricted distribution and ecological importance, direct brine discharges to Z. chilensis meadows may not be recommended.

Behavioural and physiological responses to salinization and air exposure during the ontogeny of a freshwater South American snail.

Salinization is of global concern, threatening freshwater biodiversity. Salinity tolerance is highly variable and therefore needs to be evaluated on a species-specific basis. An estuarine population of Chilina dombeiana, a freshwater gastropod endemic to Chile and classified as vulnerable, has been recently found in the Biobío River's mouth, suggesting some degree of tolerance to brackish waters. This study evaluated the survival, behaviour (medium preference) and physiology of C. dombeiana when exposed to salinities higher than freshwater, thus elucidating the potential mechanisms used to survive salinization. Chilina dombeiana belongs to the Pulmonate group;, so we evaluated oxygen uptake in air and water, aiming to evaluate emersion as a potential avoidance response to a progressive salinity increase. Complete embryo development was observed for salinities ≤ 16 PSU (practical salinity units) but hatching rates above 50% were only achieved in freshwater (0 PSU). It was also found that salinity had stage-specific effects during embryonic development. In adults, acute exposure to brackish water (12 PSU) caused a decrease in oxygen consumption (compared to freshwater), in the ammonium excretion rates and in the percentage of muscular water content. Although C. dombeiana was able to take up oxygen in both mediums, survival in air decreased over time (days), which correlates with the behavioural preference to remain submerged, even at elevated salinities. Considering the survival of adults and embryos decreased as salinity increased and the lack of an avoidance behaviour or a physiological ability to maintain homeostasis at salinities higher than freshwater, our results suggest this snail could be adversely affected by salinization in the long term. Furthermore, given the ability of C. dombeiana to uptake oxygen in both mediums, it should be considered as a facultative air breather snail, rather than a strictly aquatic species.

Salty freshwater macrophytes: the effects of salinization in freshwaters upon non-halophyte aquatic plants.

Salinization is a threat that affects aquatic ecosystems worldwide. As primary producers, freshwater macrophytes are of paramount importance in these ecosystems, however, information regarding the potential impacts of salinization upon these organisms is still scarce. In this review we provide a comprehensive and updated discussion of how freshwater macrophytes deal with salinity increase in freshwaters. We reviewed the salinity tolerance of widespread non-halophyte macrophytes through an overview of salinity tolerance mechanisms, their tolerance classification, and salinity effects at different levels of organization: from individuals to ecosystems. Thus, we demonstrated that widespread macrophytes that inhabit freshwaters display efficient salinity tolerance to salinity levels between 5 and 10 g L-1, and only a few species display tolerance to salinities higher than 10 g L-1. Widespread macrophytes demonstrated salinity tolerance of approximately 5 g L-1. Widespread macrophytes demonstrated salinity tolerance of approximately 5 g L-1. Emergent, floating and submerged species showed no significant difference in salinity tolerance. Salinity stress symptoms in freshwater macrophytes are somewhat similar to those of terrestrial plants and can show up even at slight salinity increases. Salinities higher than 1 g L-1 can negatively affect both physiology and diversity of non-halophyte macrophytes and cause long-term - and not well understood - changes in freshwater ecosystems. Salinization of freshwater ecosystems, among others threats, in combination with climate change, raise concerns about the future ecological status of freshwater ecosystems and the services they can provide.

Integrated Metabolomics and Morpho-Biochemical Analyses Reveal a Better Performance of Azospirillum brasilense over Plant-Derived Biostimulants in Counteracting Salt Stress in Tomato.

Increased soil salinity is one of the main concerns in agriculture and food production, and it negatively affects plant growth and crop productivity. In order to mitigate the adverse effects of salinity stress, plant biostimulants (PBs) have been indicated as a promising approach. Indeed, these products have a beneficial effect on plants by acting on primary and secondary metabolism and by inducing the accumulation of protective molecules against oxidative stress. In this context, the present work is aimed at comparatively investigating the effects of microbial (i.e., Azospirillum brasilense) and plant-derived biostimulants in alleviating salt stress in tomato plants by adopting a multidisciplinary approach. To do so, the morphological and biochemical effects were assessed by analyzing the biomass accumulation and root characteristics, the activity of antioxidant enzymes and osmotic stress protection. Furthermore, modifications in the metabolomic profiles of both leaves and root exudates were also investigated by ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC/QTOF-MS). According to the results, biomass accumulation decreased under high salinity. However, the treatment with A. brasilense considerably improved root architecture and increased root biomass by 156% and 118% in non-saline and saline conditions, respectively. The antioxidant enzymes and proline production were enhanced in salinity stress at different levels according to the biostimulant applied. Moreover, the metabolomic analyses pointed out a wide set of processes being affected by salinity and biostimulant interactions. Crucial compounds belonging to secondary metabolism (phenylpropanoids, alkaloids and other N-containing metabolites, and membrane lipids) and phytohormones (brassinosteroids, cytokinins and methylsalicylate) showed the most pronounced modulation. Overall, our results suggest a better performance of A. brasilense in alleviating high salinity than the vegetal-derived protein hydrolysates herein evaluated.

Streptomyces spp. enhance vegetative growth of maize plants under saline stress.

Saline stress is one of the abiotic stresses that most compromises the yield of crops and can be mitigated by plant growth-promoting rhizobacteria (PGPR). This work characterized rhizobacteria isolates from the genus Streptomyces as PGPR and evaluated their role on growth and alleviation of the effects caused by saline stress in maize (Zea mays L.). Production of indolic compounds (IC), siderophores, ACC deaminase, phenazines, and promotion of plant growth were determined to characterize bacterial isolates. Salinity tolerance was accessed by culturing the Streptomyces isolates under NaCl increasing concentrations (0-300 mM). Four Streptomyces isolates exhibiting PGPR traits and salinity tolerance were selected and their effect on tolerance of maize plants to saline stress was evaluated. Plants obtained from bacterized seeds and submitted to 100 and 300 mM NaCl were used. All Streptomyces spp. produced IC and siderophores, CLV178 being the best producer of these two compounds. ACC deaminase was detected in six of the 10 isolates (CLV95, CLV97, CLV127, CLV179, CLV193, and CLV205), while phenazines were found only in CLV186 and CLV194. All isolates were tolerant to salinity, growing at concentrations up to 300 mM NaCl, with exception of CLV188. Increased concentrations of IC were detected in most of the isolates exposed to salinity. CLV97 and CLV179 significantly promoted growth of roots and leaves of maize plants and attenuated the negative effects of salinity on plant growth. Root colonization by Streptomyces spp. was confirmed in plants cultivated 20 days under saline stress.

Salt acclimation in sorghum plants by exogenous proline: physiological and biochemical changes and regulation of proline metabolism.

KEY MESSAGE: Mitigation of deleterious effects of salinity promoted by exogenous proline can be partially explained by changes in proline enzymatic metabolism and expression of specific proline-related genes. Proline accumulation is a usual response to salinity. We studied the ability of exogenous proline to mitigate the salt harmful effects in sorghum (Sorghum bicolor) leaves. Ten-day-old plants were cultivated in Hoagland's nutrient solution in either the absence or presence of salinity (NaCl at 75 mM) and sprayed with distilled water or 30 mM proline solution. Salinity deleterious effects were alleviated by exogenous proline 14 days after treatment, with a return in growth and recovery of leaf area and photosynthetic parameters. Part of the salinity response reflected an improvement in ionic homeostasis, provided by reduction in Na+ and Cl- ions and increases in K+ and Ca2+ ions as well as increases of compatible solutes. In addition, the application of proline decreased membrane damage and did not increase relative water content. Proline-treated salt-stressed plants displayed increase in proline content, a response counterbalanced by punctual modulation in proline synthesis (down-regulation of Δ1-pyrroline-5-carboxylate synthetase activity) and degradation (up-regulation of proline dehydrogenase activity) enzymes. These responses were correlated with expression of specific proline-related genes (p5cs1 and prodh). Our findings clearly show that proline treatment results in favorable changes, reducing salt-induced damage and improving salt acclimation in sorghum plants.

Four new choanoflagellate species from extreme saline environments: Indication for isolation-driven speciation exemplified by highly adapted Craspedida from salt flats in the Atacama Desert (Northern Chile).

With this study we aim to extend the knowledge on the biogeography of craspedid choanoflagellates with additional data from extreme environments. Up to now, very little is known about choanoflagellates from extreme saline environments, as most studies have focused on marine and freshwater habitats. Though previously investigated high saline ice biota communities have indicated a possible adaptation to environments with high salt concentrations. Hypersaline endorheic basins, so-called salt flats or salares from the Atacama Desert in Northern Chile provide an intense environment regarding fluctuating and extreme salinities, which allow for studies on evolutionary adaptations of protists to hypersaline conditions. This study focused on choanoflagellate species isolated from different salt flats, their morphological characteristics using light and electron microscopy, molecular marker genes (SSU and LSU rDNA) and their salinity tolerance. Here, we described four new craspedid choanoflagellate species, highly adapted to the hypersaline environment of the Atacama Desert. This study extends our knowledge on choanoflagellate phylogeny and ecology and can become the basis for further molecular studies to understand the mechanisms of adaptations. Additionally, we emphasize the need of adding additional data such as autecological characteristics to amend species definitions, which is only possible from cultivated strains. This data would support the use of molecular data originating from metagenomic analyses also in an ecological context.

Transcriptome profiling and digital gene expression analysis of genes associated with salinity resistance in peanut

Background: Soil salinity can significantly reduce crop production, but the molecular mechanism of salinity tolerance in peanut is poorly understood. A mutant (S1) with higher salinity resistance than its mutagenic parent HY22 (S3) was obtained. Transcriptome sequencing and digital gene expression (DGE) analysis were performed with leaves of S1 and S3 before and after plants were irrigated with 250 mM NaCl. Results: A total of 107,725 comprehensive transcripts were assembled into 67,738 unigenes using TIGR Gene Indices clustering tools (TGICL). All unigenes were searched against the euKaryotic Ortholog Groups (KOG), gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and these unigenes were assigned to 26 functional KOG categories, 56 GO terms, 32 KEGG groups, respectively. In total 112 differentially expressed genes (DEGs) between S1 and S3 after salinity stress were screened, among them, 86 were responsive to salinity stress in S1 and/or S3. These 86 DEGs included genes that encoded the following kinds of proteins that are known to be involved in resistance to salinity stress: late embryogenesis abundant proteins (LEAs), major intrinsic proteins (MIPs) or aquaporins, metallothioneins (MTs), lipid transfer protein (LTP), calcineurin B-like protein-interacting protein kinases (CIPKs), 9-cis-epoxycarotenoid dioxygenase (NCED) and oleosins, etc. Of these 86 DEGs, 18 could not be matched with known proteins. Conclusion: The results from this study will be useful for further research on the mechanism of salinity resistance and will provide a useful gene resource for the variety breeding of salinity resistance in peanut.

Formation of seedlings of species from the genus passiflora under saline stress / Formação de mudas de espécies do gênero passiflora sob estresse salino

The genus Passiflora of the passion fruit crop is the most important from economic point of view. However, its cultivation in the semi-arid region is at risk due to salinity problems, requiring the identification of tolerant species, which develop better in environments with salinity problems. The objective of this study was to evaluate the effects of water salinity on growth and formation of seedlings of three species from the genus Passiflora. The treatments were distributed in a completely randomized design, adopting a 5 x 3 factorial arrangement, with five levels of irrigation water salinity (ECw) of 0.3; 1.4; 2.5; 3.6 and 4.7 dS m-1 and three species of Passiflora: gibertii; cincinnata and edulis 'BRS Gigante Amarelo', with four replicates. P. edulis surpassed the others in leaf area, shoot, root and total dry matter and Dickson index of seedling quality. Irrigation water salinity inhibits the formation of seedlings evaluated by growth in height, stem diameter and shoot, root and total dry matter of the studied species of Passiflora. The interaction between ECw and the Passiflora species interfered significantly in height, root, shoot and total dry matter and Dickson quality index. ECw above 0.3 dS m-1 affects the Dickson quality index of P. gibertii more,compared with P. edulis and P. cincinnata.

O gênero Passiflora da cultura do maracujazeiro é o importante de ponto de vista econômico. No entanto, seu cultivo na região semiárida apresenta risco, devido aos problemas de salinidade, sendo necessária a identificação de espécies tolerantes, que se desenvolvam em ambientes com problemas de salinidade. Com isso, objetivouse avaliar os efeitos da salinidade das águas no crescimento e formação de mudas de três espécies do gênero Passiflora. Os tratamentos foram distribuídos em delineamento inteiramente casualizado, usando arranjo fatorial 5 x 3, com cinco níveis de salinidade da água de irrigação (CEa) de 0,3; 1,4; 2,5; 3,6 e 4,7 dS m-1 e três espécies de Passiflora: gibertii; cincinnata e edulis BRS Gigante Amarelo, com quatro repetições. Dentre as espécies, P. edulis superou as demais em área foliar, matéria seca da parte aérea, de raiz e total e índice de qualidade de mudas de Dickson. A salinidade da água de irrigação inibe a formação de mudas avaliadas pelo crescimento em altura, diâmetro do caule, massa seca das partes aérea, raiz e total, das espécies estudadas. A interação entre CEa e as espécies de Passiflora interfere significativamente na altura, massa seca das aízes, parte aérea, total e índice de qualidade de Dickson das mudas. A irrigação com CEa acima de 0,3 dS m-1 compromete mais o índice de qualidade de Dickson da espécie P. gibertii que das espécies P. edulis e P. cincinnata.

Cambios anatómicos en raíces e hipocótilos de plántulas de Prosopis ruscifolia (Fabaceae) sometidas a estrés salino / Anatomical changes in roots and hypocotyls of Prosopis ruscifolia (Fabaceae) seedlings exposed to saline stress

ResumenProsopis ruscifolia es una especie arbórea pionera en áreas inundadas o salinas. El objetivo de este trabajo fue determinar cambios anatómicos en raíces e hipocótilos de plántulas de P. ruscifolia sometidas a estrés salino, bajo condiciones controladas. Las semillas se recolectaron en bosques nativos de la Región Chaqueña Occidental de Argentina. Las semillas se sembraron sobre toallas de papel humedecidas con soluciones salinas de 100, 200 y 300 mM de NaCl y un control humedecido con agua destilada. Se sembraron cuatro repeticiones de 50 semillas cada una, correspondientes a cada tratamiento, se ubicaron en cajas plásticas herméticas dentro de cámara de siembra a 27 ºC y con fotoperíodo de 12 horas. Doce días después de la siembra, se extrajeron plántulas para estudios anatómicos. Se estudiaron 35 plántulas correspondientes a cada tratamiento. Se midieron en raíces e hipocótilos las siguientes variables anatómicas: diámetro de la raíz principal e hipocótilo (µm), espesor de la corteza (µm), número de estratos celulares en la corteza, diámetro del cilindro central (µm), diámetro de la médula (µm), número de estratos celulares en el periciclo y diámetro tangencial de los vasos (µm). Se realizó ANOVA con diámetro de la raíz o hipocótilo como variable dependiente y espesor de la corteza, número de estratos celulares en la corteza, diámetro del cilindro central, diámetro de la médula, número de estratos celulares en el periciclo, diámetro tangencial de los vasos y concentración salina como variables independientes. El diámetro de la raíz disminuyó significativamente con el aumento de la concentración salina (P < 0.0001). El espesor de la corteza redujo su espesor a 100 mM (P < 0.0001) e incrementó el número de estratos celulares que la componen (P < 0.0002). El diámetro del cilindro central se redujo a la concentración salina de 100 mM (P < 0.0001) y el diámetro de la médula y el número de estratos celulares del periciclo (P < 0.0003) disminuyó progresivamente hasta 300 mM. El diámetro tangencial de los vasos (P < 0.0001) se redujo recién a 300 mM de NaCl. Estos cambios anatómicos podrían estar relacionados con la alteración de la expansión y división celular causada por la salinidad y comprometer la formación de raíces laterales y el almacenamiento de reservas. Los hipocótilos no mostraron cambios anatómicos significativos en respuesta al incremento en la salinidad, con excepción de la variación en la posición de estomas y un incremento en el espesor de la hipodermis. Estos cambios parecen indicar el estrés hídrico impuesto por el bajo potencial osmótico causado por las sales. Las plántulas de P. ruscifolia experimentaron cambios anatómicos en respuesta a las concentraciones salinas analizadas, en rasgos vinculados al almacenamiento de reservas, a la absorción y la conducción de agua y la formación de raíces laterales.

Abstract:Prosopis ruscifolia is a pioneer tree species in flooding or saline areas. The aim of this work was to assess anatomical changes in roots and hypocotyls of P. ruscifolia seedlings induced to saline stress under controlled conditions. Seeds, collected in natural forests of Western Chaco region in Argentina, were sown on paper towels moisturized with saline solutions of 100, 200 and 300 mM of NaCl, and a control group with distilled water. Four repetitions of 50 seeds per treatment were sown, located in hermetic polystyrene boxes, and included in a seeding chamber, at 27 ºC and 12 hours photoperiod. Were studied 35 seedlings from each saline concentration; these seedlings were processed 12 days after sown to obtain microscopic samples. The anatomical variables measured in roots and hypocotyls were the following: main root diameter (µm), bark thickness (µm), number of cell strata in bark, central cylinder diameter (µm), pith diameter (µm), number of cell strata in the pericycle and the tangential diameter of vessels (µm). ANOVA analysis were performed with hypocotyl and root diameters as the dependent variable, and bark thickness (µm), number of cell strata in the bark, the central cylinder diameter (µm), the pith diameter (µm), number of cell strata in the pericycle, the tangential diameter of vessels and the saline concentration as independent variables. Results showed that the root diameter decreased with increasing saline concentrations (P < 0.0001). The bark thickness decreased at 100 mM (P < 0.0001) and the number of cell strata of bark increased to 300 mM (P < 0.0002). The central cylinder diameter decreased at 100 mM saline concentration (P < 0.0001) and the number of cell strata of the pericycle and the pith diameter reduced progressively until 300 mM. The tangential diameter of vessels decreased at 300 mM. These anatomical changes suggested alterations in the expansion and cell division caused by the salinity, and could limit lateral roots formation and reserves storage. Hypocotyls did not show significant anatomical changes in response to increasing salinity, with exception of stomata position and an increase of the hypodermis thickness. These changes indicated that the water stress imposed by low osmotic potential is caused by increasing saline concentration. The seedlings of P. ruscifolia experienced anatomical changes in response to tested saline concentrations in traits related to reserve storage, the absorption and conduction of water, and lateral roots formation. Rev. Biol. Trop. 64 (3): 1007-1017. Epub 2016 September 01.

Fish composition and species richness in eastern South American coastal lagoons: additional support for the freshwater ecoregions of the world.

The relationships between fish composition, connectivity and morphometry of 103 lagoons in nine freshwater ecoregions (FEOW) between 2·83° S and 37·64° S were evaluated in order to detect possible congruence between the gradient of species richness and similarities of assemblage composition. Most lagoons included in the study were <2 km(2) , with a maximum of 3975 km(2) in surface area. Combined surface area of all lagoons included in the study was 5411 km(2) . Number of species varied locally from one to 76. A multiple regression revealed that latitude, attributes of morphometry and connectivity, and sampling effort explained a large amount of variability in species richness. Lagoon area was a good predictor of species richness except in low latitude ecoregions, where lagoons are typically small-sized and not affected by marine immigrants, and where non-native fish species accounted for a significant portion of species richness. Relationships between species and area in small-sized lagoons (<2 km(2) ) is highly similar to the expected number in each ecoregion, with systems located between 18·27° S and 30·15° S attaining higher levels of species richness. Similarities in species composition within the primary, secondary and peripheral or marine divisions revealed strong continental biogeographic patterns only for species less tolerant or intolerant to salinity. Further support for the FEOW scheme in the eastern border of South America is therefore provided, and now includes ecotonal systems inhabited simultaneously by freshwater and marine species of fishes.

First record of the genus Jenynsia from marine water on the coast of Punta del Este, Maldonado, Uruguay (Cyprinodontiformes: Anablepidae).

The first report of the genus Jenynsia occurring in marine waters is presented here. The evolution of high salinity tolerance within Anablepidae is discussed and a hypothesis is proposed that this characteristic is a plesiomorphic trait in Jenynsia which was probably present in the common ancestor of the Anablepidae.

Detection of genes providing salinity-tolerance in rice / Detecção de genes que conferem tolerância à salinidade em planta de arroz

The present study aimed to identify salinity-tolerant genes in three cultivars (BRS-7 Taim, BRS Querência and BRS Atalanta) of Oryza sativa L. ssp. indica S. Kato and in three cultivars (BRS Bojurú, IAS 12-9 Formosa and Goyakuman) of Oryza sativa L. ssp. japonica S. Kato. Ten days after emergence seedlings were transferred to a greenhouse and placed in a 15L vessel with half strength Hoagland nutrient solution, which was changed every four days, under controlled temperature and humidity. Plants were harvested 56 days after transfer. DNA extraction was carried out by CTAB method and salinity-tolerant genes SOS and CK1 were identified by in silico research. Amplification of gene sequence was performed with in silico primers. Bands were detected by agar gel electrophoresis and visualized under ultraviolet light after staining with ethidium bromide. Gene SOS1 fragments were present in all cultivars, except in BRS Atalanta, whereas CK1 gene was present in all evaluated cultivars. Results show that salinity-tolerant genes under analysis were identified in the two sub-species.(AU)

O estudo teve como objetivo identificar genes envolvidos na tolerância à salinidade em três cultivares (BRS-7 Taim, BRS Querência e BRS Atalanta) de Oryza sativa L. ssp. indica S. Kato e em três cultivares (BRS Bojurú, IAS 12-9 Formosa e Goyakuman) de Oryza sativa L. ssp. japonica S. Kato. As plântulas foram transferidas para casa de vegetação, sob temperatura e umidade relativa controladas, dez dias após a emergência e colocadas em bacia com capacidade para 15 litros, contendo solução nutritiva de Hoagland, meia força, a qual foi mudada em intervalos de quatro dias. A coleta foi aos 56 dias após a transferência. A extração de DNA foi realizada pelo método CTAB. Os genes SOS e CK1, envolvidos na tolerância à salinidade, foram identificados por meio de pesquisa in sílico. A amplificação das sequências do gene foi realizada utilizando-se primers também desenhados in sílico. As bandas foram detectadas por eletroforese em gel de agarose e visualizadas em luz ultravioleta após coloração com brometo de etídio. Fragmentos do gene SOS1 foram encontrados em todas as cultivares, exceto para BRS Atalanta. O gene CK1 esteve presente em todas as cultivares avaliadas. Os resultados mostram que os genes estudados estão presentes em ambas as subespécies.(AU)

Detection of genes providing salinity-tolerance in rice / Detecção de genes que conferem tolerância à salinidade em planta de arroz

The present study aimed to identify salinity-tolerant genes in three cultivars (BRS-7 Taim, BRS Querência and BRS Atalanta) of Oryza sativa L. ssp. indica S. Kato and in three cultivars (BRS Bojurú, IAS 12-9 Formosa and Goyakuman) of Oryza sativa L. ssp. japonica S. Kato. Ten days after emergence seedlings were transferred to a greenhouse and placed in a 15L vessel with half strength Hoagland nutrient solution, which was changed every four days, under controlled temperature and humidity. Plants were harvested 56 days after transfer. DNA extraction was carried out by CTAB method and salinity-tolerant genes SOS and CK1 were identified by in silico research. Amplification of gene sequence was performed with in silico primers. Bands were detected by agar gel electrophoresis and visualized under ultraviolet light after staining with ethidium bromide. Gene SOS1 fragments were present in all cultivars, except in BRS Atalanta, whereas CK1 gene was present in all evaluated cultivars. Results show that salinity-tolerant genes under analysis were identified in the two sub-species.

O estudo teve como objetivo identificar genes envolvidos na tolerância à salinidade em três cultivares (BRS-7 Taim, BRS Querência e BRS Atalanta) de Oryza sativa L. ssp. indica S. Kato e em três cultivares (BRS Bojurú, IAS 12-9 Formosa e Goyakuman) de Oryza sativa L. ssp. japonica S. Kato. As plântulas foram transferidas para casa de vegetação, sob temperatura e umidade relativa controladas, dez dias após a emergência e colocadas em bacia com capacidade para 15 litros, contendo solução nutritiva de Hoagland, meia força, a qual foi mudada em intervalos de quatro dias. A coleta foi aos 56 dias após a transferência. A extração de DNA foi realizada pelo método CTAB. Os genes SOS e CK1, envolvidos na tolerância à salinidade, foram identificados por meio de pesquisa in sílico . A amplificação das sequências do gene foi realizada utilizando-se primers também desenhados in sílico. As bandas foram detectadas por eletroforese em gel de agarose e visualizadas em luz ultravioleta após coloração com brometo de etídio. Fragmentos do gene SOS1 foram encontrados em todas as cultivares, exceto para BRS Atalanta. O gene CK1 esteve presente em todas as cultivares avaliadas. Os resultados mostram que os genes estudados estão presentes em ambas as subespécies.

Osmoregulation of juvenile marine goliath grouper (Epinephelus itajara) in low-salinity water / Osmorregulación de juveniles del mero guasa juvenil (Epinephelus itajara) en aguas de baja salinidad / Osmorregulação de juvenis do peixe garupa (Epinephelus itajara) em águas de baixa salinidade

Background: goliath grouper (Epinephelus itajara) is an economically valuable marine species and an excellent candidate for domestication for aquaculture purposes. If this grouper can osmoregulate in lowsalinity water, its cultivation can provide socio-economic benefits, for both coastal communities and the mainland agricultural sector. Objective: to evaluate the osmoregulatory capacity of juvenile goliath grouper when exposed to low-salinity water. Methods: juvenile goliath grouper (Epinephelus itajara) were either directly or gradually transferred from seawater to freshwater to test osmoregulatory ability. Body weight was assessed during acclimation and blood samples were taken to measure total osmolality and electrolytes. Results: all fish survived the transfer to freshwater and were maintained for up to 12 days after termination of the acclimation trials which lasted 72 hours. Juvenile goliath grouper were hyposmotic (342-462 mosmol/kg) to seawater and hyperosmotic (272-292 mosmol/kg) to freshwater. The gills and kidneys were found to have principal roles in the osmoregulatory processes. Numerous chloride cells were found on superficial regions of the gill filament epithelium, most likely serving to eliminate the excess of electrolytes while in seawater. The kidneys had numerous nephrons to make urine and retain electrolytes while in freshwater. Conclusions: these observations lead to the conclusions that juvenile goliath grouper have the ability to osmoregulate in freshwater and should be considered a marine euryhaline species. Such adaptability opens for consideration the possibility that goliath grouper could be successfully farmed in brackish water or even in freshwater.

Antecedentes: el mero guasa Epinephelus itajara es una especie marina de gran valor comercial y un excelente candidato a domesticar con fines acuícolas. Si el mero guasa puede osmoregular en agua de baja salinidad, su cultivo puede proporcionar beneficios socio económicos, tanto para las comunidades costeras, como al sector agropecuario en tierra firme. Objetivo: evaluar el efecto en la osmoregulación de juveniles de mero guasa expuestos a aguas de baja salinidad. Métodos: juveniles de mero guasa mantenidos en agua de mar fueron transferidos directamente o de manera gradual a agua dulce para poner a prueba su capacidad osmorreguladora. Durante el proceso de aclimatación se les evaluó el peso corporal y se extrajo sangre para medir la osmolalidad total y electrolitos. Resultados: todos los peces sobrevivieron la transferencia al agua dulce y durante 12 días más, después de la finalización de los ensayos de aclimatación que tuvieron una duración de 72 horas. Juveniles de mero guasa fueron hiposmóticos (342-462 mosmol/kg) respecto al agua de mar e hiperosmóticos (272-292 mosmol/kg) respecto al agua dulce. La histología de branquias y riñones reveló que estos órganos son de gran importancia en los procesos osmorregulatorios. Un gran número de células de cloruro fueron localizadas como parte del epitelio de los filamentos branquiales; estas células trabajan para librar al cuerpo del exceso de electrolitos mientras los peces se encuentran en el mar. En el riñón se observaron numerosas nefronas y túbulos colectores para la formación de orina y retención de electrolitos; tejidos esenciales si estos peces permanecen en agua dulce. Conclusión: estas observaciones llevan a la conclusión de que los juveniles de mero guasa tienen la capacidad de osmorregular en agua dulce y debe ser considerada una especie marina eurihalina. Tal adaptabilidad supone la posibilidad de que el mero guasa podría ser cultivado en agua salobre o incluso en agua dulce.

Antecedentes: o peixe garoupa Epinephelus itajara é uma espécie marinha de muito valor comercial a qual seria ótimo ter domesticada para sua produção industrial na aquicultura. Se o peixe garoupa pode osmoregular em água de baixa salinidade, sua cultura pode proporcionar benefícios socioeconômicos, tanto para as comunidades costeiras, quanto para o sector agrícola no interior do continente. Objetivo: avaliar a osmoregulação de juvenis do peixe garoupa expostos a águas de baixa salinidade. Métodos: juvenis do peixe Garoupa mantidos no mar foram transferidos direta ou gradualmente para água doce testando assim sua capacidade osmorregulatória. Durante o processo de aclimatização, foi avaliado o peso corporal e amostras de sangue foram coletadas para medir a osmolalidade total e alguns eletrólitos. Resultados: todos os peixes sobreviveram à transferência para água doce 12 dias mais após a conclusão dos estudos de aclimatação que se fizeram durante um período de 72 horas. Juvenis do peixe garupa foram hiposmoticos (342-462 mosmol/kg) com respeito à água marinha e hiperosmóticos (272-292 mosmol/kg) com respeito à água doce. Histologia das brânquias e os rins revelaram que estes órgãos são de grande importância nos processos de osmoregulaçao. Um grande número de células de cloreto foi localizado como parte do epitélio dos filamentos branquiais; estas células trabalham no organismo para livrar o corpo do excesso de eletrólitos enquanto os peixes estão no mar. Nos rins foram observados numerosos néfrons e ductos recoletores para a formação de urina e retenção de eletrólitos; tecidos essenciais no caso de que estes peixes permaneçam em água doce. Conclusão: estas observações levam à conclusão de que os juvenis do peixe garupa tem a capacidade de osmoregular em água doce e deve ser considerado uma espécie marinha eurialina. A adaptabilidade deste peixe em água doce supõe a possibilidade de que o peixe garupa poderia ser cultivado nesta água em criadouros no interior do continente.

Genetic diversity analysis of rice cultivars (Oryza sativa L. ) differing in salinity tolerance based on RAPD and SSR markers

Thirty rice cultivars were evaluated for salinity tolerance during the seedling stage and were divided into five tolerance groups including tolerant (T), moderately tolerant (MT), moderately susceptible (MS), susceptible (S) and highly susceptible (HS) which comprised 5, 10, 9, 4 and 2 cultivars respectively. Genetic diversity of all rice cultivars was evaluated using random amplified polymorphic DNA (RAPD) and simple sequence repeats (SSR) markers. The cultivars were evaluated for polymorphisms after amplification with 20 random decamer primers and 20 SSR primer pairs. A total of 161 RAPD markers and 190 SSR alleles were produced which revealed 68.94 percent and 89.47 percent polymorphism respectively. Mean genetic similarity coefficient was 0.82 for RAPD and 0.70 for SSR. Cluster analysis based on RAPD markers was effective in grouping cultivars based on their salt tolerance ability. Group IA1, IB and IV contained three T, three S and two HS rice cultivars respectively. The MT and MS cultivars which showed similar physiological responses to salinity were resolved into two groups: Group IA2 and Group II comprising ten and eight MT/MS cultivars respectively. Cluster analysis based on SSR markers separated rice cultivars into groups based on genetic relatedness which did not correspond to salinity tolerance level. The results from this study provided some useful implications for salt tolerance breeding programs. The evaluation of genetic similarity and cluster analysis together with salt tolerance ability provides some useful guides for assisting plant breeders in selecting suitable genetically diverse parents for the crossing program.

Water salinity and initial development of yellow passion fruit

Considering the lack of information on salt tolerance of passion fruit (Passiflora edulis) seedlings, a study was carried out to evaluate the effects of water salinity on the vigor and initial growth in a completely randomized design with 8 levels of electrical conductivity of irrigation water (ECw), varying from 1.0 to 8.0 dS m-1. Salinity delayed the germination process, but relative reduction was observed only above ECw 4.43 dS m-1. Seedling vigor and growth decreased with increasing salinity, however, water at 4 dS m-1 resulted in 85% of vigor and seedlings with more than 50% growth in comparison to the lowest salinity treatment. Based on soil salinity, the passion fruit may be considered as 'moderately tolerant' to salinity during the initial phase.

Considerando-se a inexistência de indicativos de tolerância do maracujazeiro (Passiflora edulis) à salinidade, estudaram-se, no delineamento inteiramente casualizado, os efeitos de oito níveis de condutividade elétrica da água de irrigação (CEa), variando de 1,0 a 8,0 dS m-1,sobre o vigor e a formação de mudas de maracujazeiro amarelo. A salinidade retardou a germinação, mas só houve decréscimo relativo com CEa > 4,43 dS m-1; o vigor de plântulas e o crescimento foram afetados com a salinidade, todavia, água de CE de 4 dS m-1 proporcionou 85% de vigor e mudas com crescimento superior a 50% em relação ao menor nível estudado. Com base na salinidade do solo, o maracujá amarelo pode ser considerado 'moderadamente tolerante' na fase de muda.

Water salinity and initial development of yellow passion fruit

Considering the lack of information on salt tolerance of passion fruit (Passiflora edulis) seedlings, a study was carried out to evaluate the effects of water salinity on the vigor and initial growth in a completely randomized design with 8 levels of electrical conductivity of irrigation water (ECw), varying from 1.0 to 8.0 dS m-1. Salinity delayed the germination process, but relative reduction was observed only above ECw 4.43 dS m-1. Seedling vigor and growth decreased with increasing salinity, however, water at 4 dS m-1 resulted in 85% of vigor and seedlings with more than 50% growth in comparison to the lowest salinity treatment. Based on soil salinity, the passion fruit may be considered as 'moderately tolerant' to salinity during the initial phase.

Considerando-se a inexistência de indicativos de tolerância do maracujazeiro (Passiflora edulis) à salinidade, estudaram-se, no delineamento inteiramente casualizado, os efeitos de oito níveis de condutividade elétrica da água de irrigação (CEa), variando de 1,0 a 8,0 dS m-1,sobre o vigor e a formação de mudas de maracujazeiro amarelo. A salinidade retardou a germinação, mas só houve decréscimo relativo com CEa > 4,43 dS m-1; o vigor de plântulas e o crescimento foram afetados com a salinidade, todavia, água de CE de 4 dS m-1 proporcionou 85% de vigor e mudas com crescimento superior a 50% em relação ao menor nível estudado. Com base na salinidade do solo, o maracujá amarelo pode ser considerado 'moderadamente tolerante' na fase de muda.