Low Salinity Tolerance Research Articles

Transcriptomic responses to extreme low salinity among locally adapted populations of Olympia oyster (Ostrea lurida).

The Olympia oyster (Ostrea lurida) is a foundation species inhabiting estuaries along the North American west coast. In California estuaries, O.lurida is adapted to local salinity regimes and populations differ in low salinity tolerance. In this study, oysters from three California populations were reared for two generations in a laboratory common garden and subsequently exposed to low salinity seawater. Comparative transcriptomics was then used to understand species-level responses to hyposmotic stress and population-level mechanisms underlying divergent salinity tolerances. Gene expression patterns indicate Olympia oysters are sensitive to hyposmotic stress: All populations respond to low salinity by up-regulating transcripts indicative of protein unfolding, DNA damage and cell cycle arrest after sub-lethal exposure. Among O.lurida populations, transcriptomic profiles differed constitutively and in response to low salinity. Despite two generations in common-garden conditions, transcripts encoding apoptosis modulators were constitutively expressed at significantly different levels in the most tolerant population. Expression of cell death regulators may facilitate cell fate decisions when salinity declines. Following low salinity exposure, oysters from the more tolerant population expressed a small number of mRNAs at significantly higher levels than less tolerant populations. Proteins encoded by these transcripts regulate ciliary activity within the mantle cavity and may function to prolong valve closure and reduce mortality in low salinity seawater. Collectively, gene expression patterns suggest sub-lethal impacts of hyposmotic stress in Olympia oysters are considerable and that even oysters with greater low salinity tolerance may be vulnerable to future freshwater flooding events.

Dietary supplementation of Haematococcus pluvialis improved the immune capacity and low salinity tolerance ability of post-larval white shrimp, Litopenaeus vannamei

A 25-days experiment was conducted to evaluate the effect of dietary Haematococcus pluvialis on growth, survival, immune response and stress tolerance ability of post-larval Litopenaeus vannamei. Post-larval white shrimp (mean initial weight 2.1 mg) were fed five isoenergic and isonitrogenous diets containing grade levels of Haematococcus pluvialis (0, 1.7, 3.3, 6.7 and 13.3 g kg−1 diet, respectively). Results indicated that 3.3 g Haematococcus pluvialis kg−1 diet increased the survival rate of post-larval white shrimp. Specific growth rate (SGR) and weight gain (WG) showed no difference among each groups. After the acute salinity stress (salinity decreased rapidly from 28‰ to 5‰), survival of shrimp fed 6.7 g Haematococcus pluvialis kg−1 diet significant higher than the control (P < 0.05), and the total antioxidant capacity (T-AOC) was increased with the increasing dietary Haematococcus pluvialis levels. The malonaldehyde (MDA) contents in whole body decreased with the increasing dietary Haematococcus pluvialis levels before and after the salinity stress. Before the salinity stress, relative mRNA levels of Caspase 3, Rho and Janus kinase (JAK) decreased in shrimp fed diets contain Haematococcus pluvialis. After the salinity stress, relative mRNA levels of anti-oxidative related genes and immune related genes decreased with the dietary Haematococcus pluvialis level increased to 3.3 g kg−1. Based on the effect of Haematococcus pluvialis on survival, salinity stress tolerance ability and the immune response of post-larval L. vannamei, the optimal level of Haematococcus pluvialis was 3.3–6.7 g kg−1 diet (100–200 mg astaxanthin kg−1 diet).

Physiological Mechanisms of Solanum tuberosum L. Plants’ Tolerance to Chloride Salinity

The mechanisms of potato (Solanum tuberosum L.) plants’ tolerance to chloride salinity were investigated in cv. Lugovskoi regionalized in Russia. Regenerated plants were produced in vitro from apical meristem and grown on half-strength Murashige and Skoog medium (0.5 MS) using a hydroponic unit in controlled-climate conditions. At the age of six weeks, the plants were exposed to salt stress (50–150 mM NaCl, 7 days). Plant response to salt stress was estimated by growth parameters (fresh and dry biomass of the aboveground and underground parts of plants, linear dimensions of shoot and root, area of leaf surface, and number of stolons) and physiological characteristics (level of photosynthetic pigments, accumulation of sodium, potassium, and calcium ions in the aboveground and underground parts of plants, content of proline, activity of antioxidant enzymes, plant tissue hydration, osmotic potential, and POL). It was found that, in response to salinity, the plants of potato, cv. Lugovskoi, showed a considerable inhibition of growth processes, reduction in chlorophyll a content, and suppression of stolon formation, which points to a rather low salinity tolerance of the cultivar. At the same time, under weak or moderate salt stress, the plants preserved water homeostasis owing to effective osmoregulation, actively accumulated proline that acted as a stress protector, and showed hardly any signs of oxidative stress. It was assumed that low salt tolerance of this cultivar depends on the inability of its root system to retain sodium ions and ensure selective ion transport to the aboveground part of the plant and on inefficiency of the system of sodium ions’ removal from the cytoplasm of leaf cells and their compartmentalization in the central vacuole with the purpose of reducing their toxic effect. The obtained results may be useful for working out a technique of improving salt tolerance of this cultivar by the methods of molecular genetics.

Intestinal proteome response to salinity stress in three tilapiine spp

Chronic salinity stress is likely to have significant impacts on organismal performance, especially near the upper bounds of the Critical Salinity maximum (CSmax), the “zone of resistance”. Some euryhaline fish species maintain stable internal osmolality over great salinity ranges, while close relatives tolerate much narrower ranges. Greater tolerance ranges have also been linked to reduced growth under optimum conditions. For example, breeding for improved growth rates in the tilapia species Oreochromis niloticus has inadvertently resulted in decreased tolerance to hypersaline water conditions. To examine changes in growth and stress tolerance at the cellular and tissue levels, high salinity acclimation challenges were conducted for three cichlid species, including the previously mentioned O. niloticus with reduced salinity tolerance, wild‐type (WT) O. mossambicus which exhibit tolerance to salt concentrations greater than seawater, and WT Astatotilapia burtoni which exhibit low salinity tolerance similar in range to the O. niloticus strain. Three intestinal sections were sampled from salinity‐challenged fish at 90% CSmax, and from control fish maintained in freshwater, and used to establish a standardized data‐independent acquisition (DIA) assay for label‐free quantitative proteomics for a large number of proteins in each species. Spectral libraries created by data‐dependent acquisition (DDA) and annotated using multiple search engines were used for DIA assay construction. Skyline and a sample training set were used for automated and manual assay curation to select and validate reproducible transitions and proteotypic peptides for protein quantitation. Salinity effects on intestinal protein expression patterns in each species were statistically evaluated and corresponding protein sets analyzed for gene ontology enrichment. The resulting data on salinity‐dependent intestinal proteome dynamics provide insight into biochemical processes controlling growth and stress tolerance.Support or Funding InformationFunded by BARD and NSF Grant IOS‐1355098This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Seasonal changes in photosynthesis, growth, nitrogen accumulation, and salinity tolerance of Chaetomorpha crassa (Cladophorales, Chlorophyceae)

Mass cultivation of the chlorophyte Chaetomorpha crassa has the potential to serve as a biological filter for the reduction of eutrophication in summertime Japanese waters. In order to clarify the suitability of C. crassa for this purpose, seasonal changes in its photosynthesis, growth, NO3–N uptake, nitrogen content, and salinity tolerance were investigated trimonthly from May 2011 to February 2012, with samples collected in Nagatsuraura Lagoon, northern Japan. Significant effects of seawater temperature on photosynthesis, growth, and nitrogen accumulation were also detected in all four seasons, and all parameters at summer temperatures (24–28 °C) were significantly greater than those at the temperatures of other seasons (8–20 °C). Moreover, compared to the other three seasons, C. crassa showed significantly higher growth rates at 16–4 psu and higher survival percentages at 8–2 psu during the summer. In conclusion, due to its high capacity for growth and nitrogen accumulation, and greater physiological tolerance of low salinity during the elevated temperature period, large-scale cultivation of C. crassa could play a significant role in the bioremediation of both saline and brackish waters during summer.

Developmental changes in low-salinity tolerance in larvae and juveniles of longtooth grouper, Epinephelus bruneus

Developmental changes in low-salinity tolerance in larvae and juveniles of longtooth grouper, Epinephelus bruneus

Comparative study on the physiological differences between three Chaetomorpha species from Japan in preparation for cultivation

High cellulose contents have been found in the thalli of species belonging to the green seaweed genus Chaetomorpha, indicating that they have high potential of cultivating for bioethanol production. The aim of this study was to produce critical information as a guide for the selection of suitable Chaetomorpha species from coastal areas of Japan for commercial cultivation. Three common Japanese Chaetomorpha species, Chaetomorpha crassa, Chaetomorpha moniligera, and Chaetomorpha spiralis, were collected from Matsushima Bay, northern Japan. A series of laboratory experiments were set up to compare photosynthesis, nutrient uptake, and growth, and tolerance of high temperature and low salinity. Compared with C. spiralis and C. moniligera, C. crassa exhibited significantly greater photosynthesis and growth, which was likely related to its greater nutrient uptake ability. In addition, C. crassa showed higher survival at high temperatures of 30 and 35 °C, and at low salinities of 8–4 psu. Therefore, due to its greater growth ability and higher physiological tolerance to high temperature and low salinity, C. crassa should be considered a suitable candidate with great potential for mass cultivation.

Salinity tolerance of marbled crayfishProcambarus fallaxf.virginalis

Eastern Europe comprises a significant part of the native ranges for indigenous crayfish species (ICS) belonging to the genus Astacus . This region has been largely overlooked by astacologists and considered relatively immune to the impacts of non-indigenous crayfish species (NICS). The recent discovery of two marbled crayfish Procambarus fallax f. virginalis populations in Ukraine has changed this view. Increased propagule pressure (mainly due to pet trade) has raised concerns of NICS which may negatively impair the ecosystems of Azov, Black and Caspian Seas and their tributaries inhabited by ICS. In this study, we provide the first insight into salinity tolerance of marbled crayfish. We performed a 155-day experiment using 5 different salinities (6, 9, 12, 15, and 18 ppt) and a freshwater control. Evaluation of survival, growth and reproduction suggests that marbled crayfish have a lower salinity tolerance than other crayfish species, which may limit their invasive potential in brackish environments. However, its ability to survive for more than 80 days at 18 ppt opens up the possibility of gradual dispersion and adaptation to brackish conditions. Our study highlights the need for further studies elucidating the potential for marbled crayfish to negatively impair these ecosystems.

Germination and growth of Atriplex prostrata and Plantago coronopus: Two strategies to survive in saline habitats

We investigated the effects of NaCl on germination, germination rate, growth, proline content, polyamine levels (putrescine, spermidine and spermine) and total polyamines in Atriplex prostrata and Plantago coronopus. The seeds collected from Brujuelo (salt marshes, Jaén, southern Spain) were germinated under control (water) and saline conditions (50, 100, and 200mM NaCl) for 20days at 25°C. Salinity decreased germination percentage and the germination rate in A. prostrata, and P. coronopus with increasing salt concentrations. In seedlings at day 6 and 10 of the experiment, both the length and fresh mass increased in A. prostrata for all saline treatments with respect to control, whereas in P. coronopus, only fresh mass increased with 50 and 100mM NaCl, indicating its lower salinity tolerance. With respect to proline, the maximum increase occurred with 200mM NaCl in A. prostrata; however in P. coronopus the values were low and without significant differences between treatments. The polyamine levels changed, in P. coronopus spermidine and spermine increased with salt, while in A. prostrata putrescine and spermidine decreased. These results indicate that the increase of proline was accompanied by a decrease of total polyamines (putrescine+spermidine+spermine) in A. prostrata while P. coronopus had high total polyamine levels with low values of proline, demonstrating that these plants use different strategies to adapt to saline environments.

Trophic sensitivity of invasive predator and native prey interactions: integrating environmental context and climate change

Summary Climate change is predicted to intensify the impacts of invasive species by enhancing their performance relative to their native counterparts. However, few studies have compared the performance of invasive predators and native prey, despite the fact that non‐native predators are well known to disrupt native communities. The ‘trophic sensitivity hypothesis’ suggests that predators are less tolerant of increasing environmental stress than their prey, whereas the ‘tolerant invaders hypothesis’ suggests that invaders are more tolerant than native species due to selection during the introduction process. It is therefore unclear how invasive predators will respond to increasing climate stressors. We coupled physiological measurements (thermal tolerance, thermal optima, salinity tolerance, predation rate) with environmental time‐series data to assess the effects of warming and extreme low salinity events on non‐native predators (gastropods) and native prey (oysters) from a coastal ecosystem. In general support of the trophic sensitivity hypothesis, we found that both non‐native predators exhibited lower thermal optima relative to native prey, lower salinity tolerance and one predator was less tolerant of warming. However, because warming tolerance was extremely high (i.e. habitat temperature is 7·9–21 °C below thermal tolerance), near‐term warming may first increase predator performance (consumption and growth rates), with negative effects on prey. Low salinity will likely produce heterogeneous effects on predator–prey interactions due to varying watershed sizes among estuaries that control the duration of low salinity events. The trophic sensitivity hypothesis may be a useful framework for understanding community responses to extreme climate change, which portends a decoupling of predator–prey interactions. However, we conclude that this hypothesis must be evaluated in environmental context and that coupling physiological metrics with in situ environmental data offers the best predictive power of near‐term climate change impacts on invaded communities. Within our study system, warming is likely to intensify the impacts of both invasive predators, which may greatly reduce the abundance of the native oyster, a species of conservation and restoration focus.

Stock assessment for eastern oyster seed production and field grow-out in Louisiana

There is little information on the performance of oyster populations from Louisiana estuaries limiting the ability to choose stocks for hatchery seed production and field grow-out. The objectives of this study were therefore to compare the mortality, growth, dermo (Perkinsus marinus) infection intensity and condition index of the progeny of wild oysters collected from three Louisiana estuaries differing in salinity regime and oysters specifically selected for dermo resistance. Progeny were deployed in cages in the field, along a salinity gradient in coastal Louisiana. Overall, salinity and temperature had major impacts on the mortality, growth, dermo infection intensity and condition index of oysters of all four stocks and a few differences between stocks could be shown at some sites. At the lowest salinity site, the progeny of wild oysters from Sister Lake, a low salinity estuarine lake, had the lowest mortality suggesting enhanced tolerance to low salinity conditions compared to the other stocks. At the highest salinity site, the progeny of wild oysters from Lake Calcasieu, a high salinity estuarine lake, had the lowest mortality during summer concomitant with increasing dermo infection intensities suggesting a better resistance to dermo disease compared to the other wild stocks and confirming an earlier finding. This initial result suggests that the stocks used are genetically differentiated with respect to low salinity tolerance as well as dermo-related mortality at high salinity and that stock selection for aquaculture grow-out or restoration effort will benefit from being site-specific and dependent on the dominant environmental conditions. Statement of relevanceAssessment of eastern oyster stocks in Louisiana or other Gulf of Mexico estuaries for seed production and field grow-out is lacking.

The extinct river shark Glyphis pagoda from the Miocene of Myanmar anda review of the fossil record of the genus Glyphis (Carcharhiniformes: Carcharhinidae).

We redescribe an extinct river shark, Glyphis pagoda (Noetling), on the basis of 20 teeth newly collected from three different Miocene localities in Myanmar. One locality is a nearshore marine deposit (Obogon Formation) whereas the other two localities represent terrestrial freshwater deposits (Irrawaddy sediments), suggesting that G. pagoda from the Irrawaddy sediments was capable of tolerating low salinity like the extant Glyphis. Glyphis pagoda likely reached up to at least 185 cm in total body length and was probably piscivorous. The fossil species occurs in rocks of Myanmar and eastern and western India and stratigraphically ranges at least from the Lower Miocene (Aquitanian) to thelower Upper Miocene (mid-Tortonian). Ithas been classified under at least eight other genera to date, along with numerous taxonomic synonyms largely stemming from the lack of understanding of the heterodonty in extant Glyphis in the original description. Our literature review suggests that known Miocene shark faunas, particularly those in India, are manifested with unreliable taxonomic identifications and outdated classifications that warrant the need for a comprehensive taxonomic review in order to evaluate the evolutionary history and diversity pattern of Miocene shark faunas. The genus Glyphis has a roughly 23-million-year-long history, and its success may be related to the evolution of its low salinity tolerance. While extant Glyphisspp. are considered to be particularly vulnerable to habitat degradation and overfishing, the fossil record of G. pagoda provides renewed perspective on the natural history of the genus that can be taken into further consideration for conservation biology of the extant forms.

Adaptation to climate change: trade-offs among responses to multiple stressors in an intertidal crustacean.

Trade‐offs may influence both physiological and evolutionary responses to co‐occurring stressors, but their effects on both plastic and adaptive responses to climate change are poorly understood. To test for genetic and physiological trade‐offs incurred in tolerating multiple stressors, we hybridized two populations of the intertidal copepod Tigriopus californicus that were divergent for both heat and salinity tolerance. Starting in the F2 generation, we selected for increased tolerance of heat, low salinity, and high salinity in replicate lines. After five generations of selection, heat‐selected lines had greater heat tolerance but lower fecundity, indicating an energetic cost to tolerance. Lines selected for increased salinity tolerance did not show evidence of adaptation to their respective environments; however, hypo‐osmotic selection lines showed substantial loss of tolerance to hyperosmotic stress. Neither of the salinity selection regimes resulted in diminished heat tolerance at ambient salinity; however, simultaneous exposure to heat and hypo‐osmotic stress led to decreased heat tolerance, implying a physiological trade‐off in tolerance to the two stressors. When we quantified the transcriptomic response to heat and salinity stress via RNA sequencing, we observed little overlap in the stress responses, suggesting the observed synergistic effects of heat and salinity stress were driven by competing energetic demands, rather than shared stress response pathways.

Efectos de la temperatura y salinidad sobre el crecimiento y supervivencia de juveniles de pargo Lutjanus guttatus

In Latin America snapper species have shown great potential for mariculture, including L. guttatus , but it is necessary to study physiological aspects regarding its production. The purpose of this study was to determine the effects of temperature (24, 29 and 34°C) and salinity (15, 25, 35, 45) on the growth and survival of juvenile L. guttatus . All experiments were performed in a recirculation system with daily 300% change of water; in cylindrical 80 L tanks, and three replicates per treatment. 360 specimens were used for the experiments. Experiments were performed with 360 specimens. The results showed that there are differences ( P < 0.05) in salinity-temperature interaction. The highest specific growth rate appeared in the treatment of 34°C and salinity of 15. The greatest gain in average body weight was obtained in the treatment of 34°C and salinity of 25. The longer survival was recorded in the treatment of 24°C and salinities of 15 to 35. The low salinity tolerance for this species found shows that L. guttatus has a high potential to grow in lagoon-estuarine systems of low salinity (15) and no more than 35.

Projected habitat loss for Atlantic herring in the Baltic Sea

Projected, climate-driven changes in rainfall patterns are expected to alter the salinity (S) of estuaries and larger brackish water bodies, such as the Baltic Sea. Some marine fish larvae are potentially more sensitive to low salinity than older stages, hence we compared the low salinity tolerance of Atlantic herring (Clupea harengus) larvae at the individual and population levels including four populations in the North and Baltic Seas. Acute low salinity tolerance was similar (S = 1.9–2.7) across populations and increased with increasing body size. Based on this physiological threshold and a regionally down-scaled climate model, spawning habitats in the northern and eastern Baltic Sea are projected to be largely unsuitable for herring by 2100. Although adaptive mechanisms may attenuate the effect in some species, the limited physiological tolerance of fish larvae will remain an important bottleneck for the persistence of marine fish populations in brackish waters undergoing climate-driven freshening.

Evolutionary mechanisms of habitat invasions, using the copepod Eurytemora affinis as a model system.

The study of the copepod Eurytemora affinis has provided unprecedented insights into mechanisms of invasive success. In this invited review, I summarize a subset of work from my laboratory to highlight key insights gained from studying E.affinis as a model system. Invasive species with brackish origins are overrepresented in freshwater habitats. The copepod E.affinis is an example of such a brackish invader, and has invaded freshwater habitats multiple times independently in recent years. These invasions were accompanied by the evolution of physiological tolerance and plasticity, increased body fluid regulation, and evolutionary shifts in ion transporter (V-type H(+) ATPase, Na(+), K(+)-ATPase) activity and expression. These evolutionary changes occurred in parallel across independent invasions in nature and in laboratory selection experiments. Selection appears to act on standing genetic variation during invasions, and maintenance of this variation is likely facilitated through 'beneficial reversal of dominance' in salinity tolerance across habitats. Expression of critical ion transporters is localized in newly discovered Crusalis leg organs. Increased freshwater tolerance is accompanied by costs to development time and greater requirements for food. High-food concentration increases low-salinity tolerance, allowing saline populations to invade freshwater habitats. Mechanisms observed here likely have relevance for other taxa undergoing fundamental niche expansions.

Host-microbe interactions as a driver of acclimation to salinity gradients in brown algal cultures.

Like most eukaryotes, brown algae live in association with bacterial communities that frequently have beneficial effects on their development. Ectocarpus is a genus of small filamentous brown algae, which comprises a strain that has recently colonized freshwater, a rare transition in this lineage. We generated an inventory of bacteria in Ectocarpus cultures and examined the effect they have on acclimation to an environmental change, that is, the transition from seawater to freshwater medium. Our results demonstrate that Ectocarpus depends on bacteria for this transition: cultures that have been deprived of their associated microbiome do not survive a transfer to freshwater, but restoring their microflora also restores the capacity to acclimate to this change. Furthermore, the transition between the two culture media strongly affects the bacterial community composition. Examining a range of other closely related algal strains, we observed that the presence of two bacterial operational taxonomic units correlated significantly with an increase in low salinity tolerance of the algal culture. Despite differences in the community composition, no indications were found for functional differences in the bacterial metagenomes predicted to be associated with algae in the salinities tested, suggesting functional redundancy in the associated bacterial community. Our study provides an example of how microbial communities may impact the acclimation and physiological response of algae to different environments, and thus possibly act as facilitators of speciation. It paves the way for functional examinations of the underlying host-microbe interactions, both in controlled laboratory and natural conditions.

Survival and growth of invasive Indo-Pacific lionfish at low salinities

Invasive Indo-Pacific lionfish [Pterois volitans (Linnaeus, 1758) and P. miles (Bennett, 1828)] are now established throughout the Western North Atlantic. Several studies have documented negative effects of lionfish on marine fauna including significant changes to reef fish community composition. Established populations of lionfish have been documented in several estuaries, and there is concern that the species may invade other low-salinity environments where they could potentially affect native fauna. To gain a better understanding of their lowsalinity tolerance, we exposed lionfish to four salinities [5, 10, 20 and 34 (control)]. No lionfish mortality was observed at salinities of 34, 20 or 10, but all fish died at salinity = 5 within 12 days. Lionfish survived for at least a month at a salinity of 10 and an average of about a week at 5. Fish started the experiment at an average mass of 127.9 g, which increased at a rate of 0.55 g per day while they were alive, regardless of salinity treatment. Our research indicated lionfish can survive salinities down to 5 for short periods and thus may penetrate and persist in a variety of estuarine habitats. Further study is needed on effects of salinity levels on early life stages (eggs, larvae).

Testing local and global stressor impacts on a coastal foundation species using an ecologically realistic framework.

Despite the abundance of literature on organismal responses to multiple environmental stressors, most studies have not matched the timing of experimental manipulations with the temporal pattern of stressors in nature. We test the interactive effects of diel-cycling hypoxia with both warming and decreased salinities using ecologically realistic exposures. Surprisingly, we found no evidence of negative synergistic effects on Olympia oyster growth; rather, we found only additive and opposing effects of hypoxia (detrimental) and warming (beneficial). We suspect that diel-cycling provided a temporal refuge that allowed physiological compensation. We also tested for latent effects of warming and hypoxia to low-salinity tolerance using a seasonal delay between stressor events. However, we did not find a latent effect, rather a threshold survival response to low salinity that was independent of early life-history exposure to warming or hypoxia. The absence of synergism is likely the result of stressor treatments that mirror the natural timing of environmental stressors. We provide environmental context for laboratory experimental data by examining field time series environmental data from four North American west coast estuaries and find heterogeneous environmental signals that characterize each estuary, suggesting that the potential stressor exposure to oysters will drastically differ over moderate spatial scales. This heterogeneity implies that efforts to conserve and restore oysters will require an adaptive approach that incorporates knowledge of local conditions. We conclude that studies of multiple environmental stressors can be greatly improved by integrating ecologically realistic exposure and timing of stressors found in nature with organismal life-history traits.

Selection of plant growth-promoting bacteria in sweet sorghum (Sorghum bicolor (L.) Moench) under the effects of salinity

Background Sorghum, a grassy non-halophyte, it is both drought and salinity tolerant, and is considered a promising crop for semiarid regions. During the last 20 years, its culture has expanded in Brazilian production by 780%, reaching 1,928,970 tons in 2009 [1]. Salinization of the soil and lack of rain are increasing constraints in semiarid regions. They predominate in northeastern Brazil. This has helped limit the production of plant biomass, which is the basis of agricultural activity. The advantages of sorghum in these conditions can be improved still further by using plant growth-promoting bacteria (PGPB) for the biological processes of nitrogen fixation, and hormone production, as well as others [2]. Endophytic bacteria can secrete up to one half of the nitrogen they fix, and plants may then assimilate the nitrogen efficiently [3]. Inoculation with Azotobacter chroococcum has been shown to attenuate stress in maize grown in saline soil [4]. In this study, we evaluated the action of PGPB on a “Wray” saccharine variety with low salinity tolerance.