Search

Background and aims: India is one of the countries being projected as the salinization hotspots in the near future. To identify novel donors imparting salt tolerance, barley mini-core collection comprising 107 Hordeum vulgare germplasm and 3 wild accessions from the Indian National Genebank were evaluated under salt stress. Methods: Barley accessions were screened under salt stress (200 mM NaCl) at early growth and the adult plant stage based on morpho-physiological traits including salt uptake parameters. Further, the possible role of candidate gene Hordeum vulgare root abundant factor (HvRAF) was studied by deciphering allelic variation and expression analysis in selected salt tolerant and susceptible accessions. Results: Analysis of variance revealed a significant effect of salinity on all traits and elucidated profound genotypic variation. Salinity caused a drastic reduction in growth and severely affected ion homeostasis resulting in decline in grain yield by 65.35% compared to control. Accessions EC0578359, EC0578251, IC0547723, EC0123148, EC0299361, EC0177250 and IC0247671 were identified as the most promising salt-tolerant genotypes. Further investigation of allelic variation in HvRAF revealed a total of 26 SNPs, of which 10 were non-synonymous, 8 were synonymous and 5 were conserved. Haplotype variant analysis indicated two major haplotypic groups (Hap 1 and Hap 2) for HvRAF, of which the Hap 2 was found to be more prevalent than Hap 1. Conclusions: Salt-tolerant phenotype exhibited the physiological basis of tolerance and upregulated expression of HvRAF, although none of the identified Hap groups could be associated with salt tolerance suggesting the governance of trait by multiple loci. [ABSTRACT FROM AUTHOR]

To fish-out novel salt-tolerance genes, metagenomic DNA of moderately saline sediments of India's largest hypersaline Sambhar Lake was cloned in fosmid. Two functionally-picked clones helped the Escherichia coli host to tolerate 0.6 M NaCl. Deep sequencing of their fosmid DNA insert revealed 32-37% of genes to encode transporters, mostly belonging to ABC (ATP-Binding Cassette)-type, but none specific to channel Na + . The complete metagenome sequence of Sambhar Lake brines, and reanalysed data of twelve other hypersaline metagenome sequences, however, have only around 5% transporter genes, suggesting metagenomic DNA fragments being biasedly-cloned during functional screening. Almost half of the ~ 40 Kb inserts in the two clones was shared, and encode several transporters, and some transposase. This advocates that these transporter-loaded DNA lengths are shuttled among microorganisms of hypersaline environments. Interestingly, one clone showed retarded growth with prominent cell disruptions in scanning electron microscopic images, when fosmid copy number was increased or transporters were NaCl-induced. Its cloned insert exclusively has three genes, encoding a structurally functional ATP-binding protein and its efflux component, whose possible overexpression led to membrane crowding and cell rupture. Thus, microorganisms thriving in hypersaline lakes have plentiful ABC transporters that are mutually shared among themselves. These novel salt tolerance genes have future agricultural biotechnological potential., Competing Interests: Declarations. Conflict of interest: The authors declare no financial or non-financial conflict of interest that is directly or indirectly related to the work submitted for publication., (© 2025. The Author(s), under exclusive licence to Springer Nature Japan KK.)

An intense black pigmented halotolerant yeast GUBPC1, was obtained from the solar salterns of Nerul, Goa-India. The isolate could tolerate 0 to 20 % NaCl. FE-SEM analysis revealed its polymorphic nature, exhibiting oval cells at higher salt concentrations and filamentous spindle like shapes at lower concentrations. Initially, the cells appear oval, yeast like in shape but gradually after 15 days of incubation, it becomes elongated and undergoes budding, exhibiting various budding patterns, from single polar bud to bipolar buds with annellidic ring, to lateral buds and eventually forming filamentous hyphae. The intracellular black pigment was identified as melanin based on ultraviolet-visible spectroscopy analysis. The molecular identification of the culture showed closest similarity with Hortaea werneckii. Plant polymer-degrading enzymatic activities such as cellulase, laccase, chitinase, xylanase, pectinase, amylase and protease were exhibited by the isolate GUBPC1. To further understand and explore its biotechnological potential, we performed whole-genome sequencing and analysis. The obtained genome size was 26.93 Mb with 686 contigs and a GC content of 53.24 %. We identified 9383 protein-coding genes, and their functional annotation revealed the presence of 435 CAZyme genes and 16 functional genes involved in secondary metabolite synthesis, thus providing a basis for its potential value in various biotechnological applications., (Copyright © 2024 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

Strain MP-1014 T , an obligate halophilic actinobacterium, was isolated from the mangrove soil of Thandavarayancholanganpettai, Tamil Nadu, India. A polyphasic approach was utilized to explore its phylogenetic position completely. The isolate was Gram-positive, filamentous, non-motile, and coccoid in older cultures. Ideal growth conditions were seen at 30 °C and pH 7.0, with 5% NaCl (W/V), and the DNA G + C content was 73.3%. The phylogenic analysis of this strain based upon 16S rRNA gene sequence revealed 97-99.8% similarity to the recognized species of the genus Isoptericola. Strain MP-1014 T exhibits the highest similarity to I. sediminis JC619 T (99.7%), I. chiayiensis KCTC19740 T (98.9%), and subsequently to I. halotolerans KCTC19646 T (98.6%), when compared with other members within the Isoptericola genus (< 98%). ANI scores of strain MP-1014 T are 86.4%, 84.2%, and 81.5% and dDDH values are 59.7%, 53.6%, and 34.8% with I. sediminis JC619 T , I. chiayiensis KCTC19740 T and I. halotolerans KCTC19646 T respectively. The major polar lipids of the strain MP-1014 T were phosphatidylinositol, phosphatidylglycerol, diphosphotidylglycerol, two unknown phospholipids, and glycolipids. The predominant respiratory menaquinones were MK 9 (H 4 ) and MK 9 (H 2 ). The major fatty acids were anteiso-C 15:0 , anteiso-C 17:0 , iso-C 14:0 , C 15:0, and C 16:0 . Also, initial genome analysis of the organism suggests it as a biostimulant for enhancing agriculture in saline environments. Based on phenotypic and genetic distinctiveness, the strain MP-1014 T represents the novel species of the genus Isoptericola assigned Isoptericola haloaureus sp. nov., is addressed by the strain MP-1014 T , given its phenotypic, phylogenetic, and hereditary uniqueness. The type strain is MP-1014 T [(NCBI = OP672482.1 = GCA&#95;036689775.1) ATCC = BAA 2646 T ; DSMZ = 29325 T ; MTCC = 13246 T ]., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)

Salinity stress is the most prominent stress impacting rice productivity worldwide. In the past, several quantitative trait loci (QTLs) for salinity tolerance had been identified in rice, however their utilization in rice breeding programs is largely confounded due to the unwanted linkage drag associated with the QTL region. Thus, it is strongly desirable to delimit the QTL region to a least possible chromosomal interval minimising any unwanted association. Addressing this, we have evaluated 68 recombinant inbred lines (RILs) derived from a cross between a salinity tolerant parent 'Kolajoha' and a salinity sensitive parent 'Ranjit' for identification of QTL(s) involved in imparting salinity tolerance at seedling stage. Genotyping by sequencing approach (GBS) was followed for SNP identification at genome wide scale. Around 3649 SNPs were identified by GBS method initially at 20% minor allele frequency. After filtering of SNPs with polymorphism with less than 10–15% of missing data, a total of 1248 SNPs were mapped to 1247 recombination points and the genetic map was constructed with a total map length of 1201.21 cM and resolution of 0.95 cM between markers. For 10 traits, a total of 23 additive QTLs were identified of which only 1 was a major QTL and 22 were minor QTLs. The average QTL interval size is about 2945 kb. Epistatic QTL mapping had identified one pair of QTLs that contribute significantly in the phenotypic variation of traits among the RILs. Total 1895 genes were identified in the QTL intervals, majority of them are located in Chr1 of rice genome between 22.09 and 38.29 Mb region. Although, this region is not very narrow, some of the genes falling in this region can be utilized for validation of QTLs in future. One differentially methylated region was found to be colocalized within the QTL intervals determined in Chr2 which indicates their potential role in epigenetic modifications in improving stress tolerance in rice. [ABSTRACT FROM AUTHOR]

Salicornia brachiata (Roxb.) is an important euhalophyte for ecological rehabilitation of salt‐affected soil. The aim of this study was to investigate the population structure of S. brachiata and evaluate its ecophysiological responses throughout its lifespan. Six different salt marshes along the Gujarat Coast, India, were visited regularly to monitor and quantify the ecophysiological responses of S. brachiata. Vegetation index analyses confirmed the dominance of halophytic vegetation at these sites. The low solute potential in shoots of S. brachiata helped plants to conserve water and use water economically under physiologically dry conditions. The accumulation of Na+ increased as the plants matured, while K+, Mg+2 and Cl− contents decreased. There was a higher proportion of inorganic solutes than organic solutes throughout the lifespan of S. brachiata. The estimated contributions of different solutes to osmotic adjustment were consistent with their accumulation levels. The estimated contribution of inorganic solutes to solute potential was significantly higher than that of organic solutes. The results indicated that the uptake of inorganic solutes generated a more negative solute potential, which helped plants to conserve water and save the energy required to synthesize the organic solutes to maintain osmotic homeostasis. The results of this study provide physiological insights into the role of inorganic solutes in the salt acclimation process and reveal aspects of the salt acclimation strategies of this euhalophyte. This information will be useful for predicting the impact of S. brachiata populations on halophytic vegetation and for designing saline‐agriculture strategies for optimum yields in degraded salt‐affected soil ecosystems. [ABSTRACT FROM AUTHOR]

Present study was conducted in the Department of Botany, Government College University, Faisalabad and Agricultural Biotechnology Research Institute, AARI, Faisalabad, Pakistan during 2010-11 to explore somaclonal variation for genetic variability and salt tolerant induction in ten varieties of wheat (Chenab-70, Punjab-76, Pasban-90, Inqulab-91, Punjab-96, Uqab-2000, AS-2002, Bhakkar-2000, LU-26S and Ufaq-2002) at four salinity levels. The somaclones of various wheat genotypes along with their parents were sown in pots having artificially developed four levels of salinity (0, 4, 8 and 12 dSm-1) using NaCl salt to study and compare different agronomic traits i.e. number of spikes per plant, number of grains per spike, 100 grain weight and yield per plant among themselves. It was observed that increase in salinity level decreased number of spikes, spikelets, 100 grain weight and yield per plant. The maximum 100 grain weight (4.45 g) in control treatment was observed in AS-2002(S) and Bhakkar-2000(S) (4.37g) followed by Inqalab-91(P) (3.55g) and Punjab-76(S) (3.49 g) as compared to other somaclones of wheat. Uqab-2000(S) was also at par with its parent Uqab-2002(S). At EC level of 4dSm-1, Inqalab- 91(S), Inqalab-91(P) and Bhakkar-2000(P) were salt tolerant. At EC 8dSm-1, Bhakkar-2000(P) and LU-26S(S) were noted as the best tolerant while at EC12dSm-1 Inqalab-91(S) was superior to all other genotypes. As far as yield per plant is concerned somaclones Inqalab-91(S) and Bhakkar-2000(P) were found salt tolerant at 8dSm-1 in yield per plant. It is concluded that wheat somaclones found superior to their mother plants may be released as a new variety after testing at national level. [ABSTRACT FROM AUTHOR]

Copyright of Tropical Ecology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Porteresia coarctata (Syn = Oryza coarctata) is a tetraploid wild rice growing abundantly in the coastal region of India and some other Asian countries. The salt tolerance property of this mangrove associate has been dealt with by a number of workers earlier. The distinct morphology and leaf architecture enabling the plant to exclude salt is a characteristic feature of Porteresia in comparison with Oryza sp. A number of genes have been isolated and characterized from Porteresia that are related to the salt-tolerance property of the plant. Evidence have accumulated that some pathways critical to salt tolerance are in operation in Porteresia of which the inositol metabolic pathway has been recently elaborated. Some of the enzymes of Porteresia have been shown to function as salt-tolerant under in vitro studies giving a clue that this wild halophytic rice may have evolved genes and proteins capable of functioning under a salt environment. Bioprospecting of such genes and proteins coupled with genomic and proteomic approaches remain an exciting area of research in evaluating this plant as a model for salt tolerance for the rice plant. [ABSTRACT FROM AUTHOR]

Imidazolium-based ionic liquids (IL) with short-alkyl side chain such as 1-ethyl-3-methyl-imidazolium chloride ([Emim]Cl) and 1-butyl-3-methyl-imidazolium chloride ([Bmim]Cl) has immense application potential including in lignocellulosic bioenergy production. But they are toxic to most microorganisms, and those isolated from different environments as IL-tolerant have salt tolerance capabilities. This study evaluates the relationship between salt and [Emim]Cl tolerance of microorganisms using different salinity sediments (2-19%) and brines (35%) of India's largest inland hypersaline lake, Sambhar in Rajasthan as the model system. While samples with 2% and 35% salinities do not yield any [Emim]Cl (100 mM) tolerant colonies, others have 6-50% colonies tolerant to the IL. Similar trend was observed with 50 mM [Bmim]Cl. Moderate halophilic isolates of genera Halomonas and Bacillus (growth in 0.7-3.0 M NaCl) isolated from the sediments could grow in as high as 375 mM [Emim]Cl, or 125 mM [Bmim]Cl facilitated by higher synthesis, and uptake of organic osmolytes; and up to 1.7-fold increased activity of active efflux pumps. [Bmim]Cl was more toxic than [Emim]Cl in all performed experiments. [Emim]Cl-adapted cells could trounce IL-induced stress. Interestingly, enrichment with 100 mM [Emim]Cl resulted in increase of IL-tolerant colonies in all sediments including the one with 2% salinity. However, the salt saturated brines (35%) do not yield any such colony even after repeated incubations. Extreme halophilic archaea, Natronomonas (growth in 3.0-4.0 M NaCl) isolated from such brines, were exceedingly sensitive to even 5 mM [Emim]Cl, or 1 mM [Bmim]Cl. Two additional extremophilic archaea, namely Haloferax and Haladaptatus were also sensitive to the tested ILs. Archaeal sensitivity is possibly due to the competitive interaction of [Emim] + with their acidic proteome (15.4-17.5% aspartic and glutamic acids, against 10.7-12.9% in bacteria) that they maintain to stabilize the high amount of K + ion accumulated by salt-in strategy. Thus, general salt adaptation strategies of moderate halophilic bacteria help them to restrain toxicity of these ILs, but extremophilic archaea are highly sensitive and demands meticulous use of these solvents to prevent environmental contamination., (Copyright © 2019 Elsevier Inc. All rights reserved.)

A haloalkaliphilic bacterium was isolated from salt-enriched soil of Mithapur, Gujarat (India) and identified as Bacillus agaradhaerens Mi-10-6₂ based on 16S rRNA sequence analysis (NCBI gene bank accession, GQ121032). The bacterium was studied for its α-amylase characteristic in the presence of organic solvents. The enzyme was quite active and it retained considerable activity in 30% (v/v) organic solvents, dodecane, decane, heptane, n-hexane, methanol, and propanol. At lower concentrations of solvents, the catalysis was quite comparable to control. Enzyme catalysis at wide range of alkanes and alcohol was an interesting finding of the study. Mi-10-6₂ amylase retained activity over a broader alkaline pH range, with the optimal pH at 10-11. Two molars of salt was optimum for catalysis in the presence of most of the tested solvents, though the enzyme retained significant activity even at 4 M salt. With dodecane, the optimum temperature shifted from 50 °C to 60 °C, while the enzyme was active up to 80 °C. Over all, the present study focused on the effect of organic solvents on an extracellular α-amylase from haloalkaliphilic bacteria under varying conditions of pH, temperature, and salt.

Purification and characterization of halotolerant, thermostable alkaline L-glutaminase from a Bacillus sp. LKG-01 (MTCC 10401), isolated from Gangotri region of Uttarakhand Himalaya, is being reported in this paper. Enzyme has been purified 49-fold from cell-free extract with 25% recovery (specific activity 584.2 U/mg protein) by (NH₄)₂SO₄ precipitation followed by anion exchange chromatography and gel filtration. Enzyme has a molecular weight of 66 kDa. L-Glutaminase is most active at pH 11.0 and stable in the pH range 8.0-11.0. Temperature optimum is 70 °C and is completely stable after 3 h pre-incubation at 50 °C. Enzyme reflects more enhanced activity with 1-20% (w/v) NaCl, which is further reduced to 80% when NaCl concentration was increased up to 25%. L-Glutaminase is almost active with K⁺, Zn²⁺, and Ni²⁺ ions and K(m) and V(max) values of 240 μM and 277.77 ± 1.1 U/mg proteins, respectively. Higher specific activity, purification fold, better halo-tolerance, and thermostability would make this enzyme more attractive for food fermentation with respect to other soil microbe derived L-glutaminase reported so far.