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The World of the Salt Marsh is a wide-ranging exploration of the southeastern coast-its natural history, its people and their way of life, and the historic and ongoing threats to its ecological survival. Focusing on areas from Cape Hatteras, North Carolina, to Cape Canaveral, Florida, Charles Seabrook examines the ecological importance of the salt marsh, calling it \"a biological factory without equal.\" Twice-daily tides carry in a supply of nutrients that nourish vast meadows of spartina (Spartina alterniflora)-a crucial habitat for creatures ranging from tiny marine invertebrates to wading birds. The meadows provide vital nurseries for 80 percent of the seafood species, including oysters, crabs, shrimp, and a variety of finfish, and they are invaluable for storm protection, erosion prevention, and pollution filtration. Seabrook is also concerned with the plight of the people who make their living from the coast's bounty and who carry on its unique culture. Among them are Charlie Phillips, a fishmonger whose livelihood is threatened by development in McIntosh County, Georgia, and Vera Manigault of Mount Pleasant, South Carolina, a basket maker of Gullah-Geechee descent, who says that the sweetgrass needed to make her culturally significant wares is becoming scarcer. For all of the biodiversity and cultural history of the salt marshes, many still view them as vast wastelands to be drained, diked, or \"improved\" for development into highways and subdivisions. If people can better understand and appreciate these ecosystems, Seabrook contends, they are more likely to join the growing chorus of scientists, conservationists, fishermen, and coastal visitors and residents calling for protection of these truly amazing places.

Limonium bicolor , a typical recretohalophyte that lives in saline environments, excretes excessive salt to the environment through epidermal salt glands to avoid salt stress. The aim of this study was to screen for L. bicolor genes involved in salt secretion by high-throughput RNA sequencing. We established the experimental procedure of salt secretion using detached mature leaves, in which the optimal salt concentration was determined as 200 mM NaCl. The detached salt secretion system combined with Illumina deep sequencing were applied. In total, 27,311 genes were annotated using an L. bicolor database, and 2040 of these genes were differentially expressed, of which 744 were up-regulated and 1260 were down-regulated with the NaCl versus the control treatment. A gene ontology enrichment analysis indicated that genes related to ion transport, vesicles, reactive oxygen species scavenging, the abscisic acid-dependent signaling pathway and transcription factors were found to be highly expressed under NaCl treatment. We found that 102 of these genes were likely to be involved in salt secretion, which was confirmed using salt-secretion mutants. The present study identifies the candidate genes in the L. bicolor salt gland that are highly associated with salt secretion. In addition, a salt-transporting pathway is presented to explain how Na + is excreted by the salt gland in L. bicolor . These findings will shed light on the molecular mechanism of salt secretion from the salt glands of plants.

Excess soluble salts in soil (saline soils) are harmful to most plants. Salt imposes osmotic, ionic, and secondary stresses on plants. Over the past two decades, many determinants of salt tolerance and their regulatory mechanisms have been identified and characterized using molecular genetics and genomics approaches. This review describes recent progress in deciphering the mechanisms controlling ion homeostasis, cell activity responses, and epigenetic regulation in plants under salt stress. Finally, wehighlight research areas that require further research to reveal new determinants of salt tolerance in plants.

Soil salinization is a widespread hindrance that endangers agricultural production and ecological security. High salt concentrations in saline soils are primarily caused by osmotic stress, ionic toxicity and oxidative stress, which have a negative impact on plant growth and development. In order to withstand salt stress, plants have developed a series of complicated physiological and molecular mechanisms, encompassing adaptive changes in the structure and function of various plant organs, as well as the intricate signal transduction networks enabling plants to survive in high-salinity environments. This review summarizes the recent advances in salt perception under different tissues, physiological responses and signaling regulations of plant tolerance to salt stress. We also examine the current knowledge of strategies for breeding salt-tolerant plants, including the applications of omics technologies and transgenic approaches, aiming to provide the basis for the cultivation of salt-tolerant crops through molecular breeding. Finally, future research on the application of wild germplasm resources and muti-omics technologies to discover new tolerant genes as well as investigation of crosstalk among plant hormone signaling pathways to uncover plant salt tolerance mechanisms are also discussed in this review.

The effects of short-term salt stress on gas exchange and the regulation of photosynthetic electron transport were examined in Arabidopsis (Arabidopsis thaliana) and its salt-tolerant close relative Thellungiella (Thellungiella halophila). Plants cultivated on soil were challenged for 2 weeks with NaCl. Arabidopsis showed a much higher sensitivity to salt than Thellungiella; while Arabidopsis plants were unable to survive exposure to greater than 150 mM salt, Thellugiella could tolerate concentrations as high as 500 mM with only minimal effects on gas exchange. Exposure of Arabidopsis to sublethal salt concentrations resulted in stomatal closure and inhibition of CO₂ fixation. This lead to an inhibition of electron transport though photosystem II (PSII), an increase in cyclic electron flow involving only PSI, and increased nonphotochemical quenching of chlorophyll fluorescence. In contrast, in Thellungiella, although gas exchange was marginally inhibited by high salt and PSI was unaffected, there was a large increase in electron flow involving PSII. This additional electron transport activity is oxygen dependent and sensitive to the alternative oxidase inhibitor n-propyl gallate. PSII electron transport in Thellungiella showed a reduced sensitivity to 2'-iodo-6-isopropyl-3-methyl-2',4,4'-trinitrodiphenylether, an inhibitor of the cytochrome b₆f complex. At the same time, we observed a substantial up-regulation of a protein reacting with antibodies raised against the plastid terminal oxidase. No such up-regulation was seen in Arabidopsis. We conclude that in salt-stressed Thellungiella, plastid terminal oxidase acts as an alternative electron sink, accounting for up to 30% of total PSII electron flow.

Our research aims at studying the Mediterranean salt-tectonic supergiant. Its geological history includes two noncoeval peaks of salt accumulation: the Triassic and the most known Late Miocene–Messinian. Both peaks are associated with the main tectonic events in the history of the Neo-Tethys and its frame. The Triassic peak is associated with the rift-related emplacement of the Neo-Tethys, while the Messinian peak is associated with the terminal phases of its closure during collision. The author has attempted to substantiate the presence of more ancient buried salt strata in the substrate and at the margins of the Messinian salt basins. The processes of intensive folding of these strata during the collision of paleocontinents and paleomicrocontinents were accompanied by the removal of salt upward from its original location and could have contributed to the accumulation of salts at the Messinian level. This article is based on the results of the author’s long-term integrated lithological and tectonic studies within salt-bearing sedimentary basins in Russia and around the world, as well as a broad generalization of the data available on the Mediterranean region. The article summarizes and analyzes geological and tectonic information on the current distribution of Miocene and Triassic salts in the Mediterranean, as well as their relationships. In addition, the study reveals the spatial relationships between salt deposits, identifies the main morphokinetic types of salt bodies, and characterizes their features in different areas of the Mediterranean. Currently, the pattern of the initial distribution of largely residual Triassic salts has been reconstructed. A key feature of this pattern is the maximum salt deposition along paleorift systems that preceded the formation of passive margins of paleocontinents and paleomicrocontinents. Possible changes in the salt bodies during tectonokinematic transformations in the region and their distribution pattern by the beginning of the Messinian are considered. It has been concluded that the Messinian salt accumulation basins were mainly located within the inner parts of zones of the pre-Messinian distribution of Triassic salts. The collision of paleocontinents and paleomicrocontinents, which intensified at the end of the Miocene, led to a significant increase in the intensity of compression, shearing and disruption of brine-salt sedimentary complexes, widespread along their passive paleomargins. These processes were also accompanied by large-scale tectonokinematic removal of Triassic salt-bearing deposits from these complexes. All this created material prerequisites for their involvement in the allochthonous and neoautochthonous accumulation of salts at the Messinian level and served as one of the probable causes of the Messinian Salinity Crisis.

Background Alfalfa ( Medicago sativa L.) experiences many negative effects under salinity stress, which may be mediated by recurrent selection . Salt-tolerant alfalfa may display unique adaptations in association with rhizobium under salt stress. Results To elucidate inoculation effects on salt-tolerant alfalfa under salt stress, this study leveraged a salt-tolerant alfalfa population selected through two cycles of recurrent selection under high salt stress. After experiencing 120-day salt stress, mRNA was extracted from 8 random genotypes either grown in 0 or 8 dS/m salt stress with or without inoculation by Ensifer meliloti . Results showed 320 and 176 differentially expressed genes (DEGs) modulated in response to salinity stress or inoculation x salinity stress, respectively. Notable results in plants under 8 dS/m stress included upregulation of a key gene involved in the Target of Rapamycin (TOR) signaling pathway with a concomitant decrease in expression of the SNrK pathway. Inoculation of salt-stressed plants stimulated increased transcription of a sulfate-uptake gene as well as upregulation of the Lysine-27-trimethyltransferase (EZH2), Histone 3 (H3), and argonaute (AGO, a component of miRISC silencing complexes) genes related to epigenetic and post-transcriptional gene control. Conclusions Salt-tolerant alfalfa may benefit from improved activity of TOR and decreased activity of SNrK1 in salt stress, while inoculation by rhizobiumstimulates production of sulfate uptake- and other unique genes.