Salt-tolerant Genotypes Research Articles

Assessment of morphophysiological parameters of resistance of various varieties of winter rye to chloride salinity in laboratory conditions

Determining the tolerance of cultivated plants to salts is considered important and necessary in breeding practice in areas with primary and secondary soil salinization. This article examines the effect of salinity (NaCl) in laboratory conditions on the growth and development of plants of three varieties of winter rye (Chusovaya, Yantarnaya, Alisa) and the effectiveness of early diagnosis on resistance to the stress factor. The purpose of the study was to determine the resistance of winter rye varieties to chloride salinity based on the variability of morphophysiological characteristics under simulated conditions. Based on the identified differences in indicators characterizing the growth processes of plants in vegetation vessels in the control and on the substrate with NaCl, the varieties according to resistance to salt stress are distributed in the following order: Chusovaya, Yantarnaya, Alisa. The data obtained indicate the specificity of the response of varieties to a stress factor. It is shown that for a more objective characterization of genotypes for salt tolerance, a comprehensive study of traits (seed germination, morphometric parameters of shoots and roots, chlorophyll content in leaves, plant biomass) is necessary. The results of the study can be used in the selection of initial forms for the selection of winter rye, as well as in the cultivation of the studied varieties in different agro-ecological conditions.

Interactions between Brassinosteroids and Strigolactones in Alleviating Salt Stress in Maize.

Exogenous brassinolide (BR) and strigolactones (SLs) play an important role in alleviating salt stress in maize. We studied the morphological and physiological responses of the salt-sensitive genotype PH4CV and salt-tolerant genotype Zheng58 to BR (1.65 nM), SL (1 µM), and BS (1.65 nM BR + 1 µM SL) under salt stress. Phenotypic analysis showed that salt stress significantly inhibited the growth of maize seedlings and significantly increased the content of Na+ in the roots. Exogenous hormones increased oxidase activity and decreased Na+ content in the roots and mitigated salt stress. Transcriptome analysis showed that the interaction of BR and SL is involved in photosynthesis-antenna proteins, the TCA cycle, and plant hormone signal transduction pathways. This interaction influences the expression of chlorophyll a/b-binding protein and glucose-6-phosphate isomerase 1 chloroplastic, and aconitase genes are affected. Furthermore, the application of exogenous hormones regulates the expression of genes associated with the signaling pathways of cytokinin (CK), gibberellins (GA), auxin (IAA), brassinosteroid (BR), abscisic acid (ABA), and jasmonic acid (JA). Additionally, exogenous hormones inhibit the expression of the AKT2/3 genes, which are responsible for regulating ion transduction and potassium ion influx. Four candidate genes that may regulate the seedling length of maize were screened out through WGCNA. Respective KOG notes concerned inorganic ion transport and metabolism, signal transduction mechanisms, energy production and conversion, and amino acid transport and metabolism. The findings of this study provide a foundation for the proposition that BR and SL can be employed to regulate salt stress alleviation in maize.

Evaluation of Mung Bean Accessions for Salt Tolerance Based on Germination and Seedling Traits

Ten mung bean accessions collected from Bangladesh Agricultural Research Institute were exposed to two salinity levels (control and 8 dS m−1) to observe the sensitivity of their germination and early seedling traits. The observations were recorded on germination percentage, rate of germination, coefficient of germination, shoot length, root length and seedling dry weight. The accessions, salinity levels and their interaction exhibited significant differences for all the traits. The mean performance of all the traits reduced under salt stress as compared to control. Salt tolerant accessions showed less reduction in their germination and seedling traits under salinity than the other accessions tested. Considering salt tolerance index (STI) based on seedling dry weight, the order of tolerance was BD- 6882 > BD-10022 > BD-10024 > BD-10026 > BD-10023 > BD-10027 > BD-6885 > BD-6887 > BD- 6884 > BD-6875. Based on relative total dry weight (RTDW), three accessions viz. BD-6882, BD- 10022 and BD-10024 were identified as salt tolerant and other seven as moderately salt tolerant. The identified salt tolerant accessions could be a useful stock for further breeding programs to develop salt tolerant mung bean genotype of considerable economic value. Bangladesh Agron. J. 2024, 26(2): 16-26

QTL Detection of Salt Tolerance at Soybean Seedling Stage Based on Genome-Wide Association Analysis and Linkage Analysis.

The utilization of saline land is a global challenge, and cultivating salt-tolerant soybean varieties is beneficial for improving the efficiency of saline land utilization. Exploring the genetic basis of salt-tolerant soybean varieties and developing salt-tolerant molecular markers can effectively promote the process of soybean salt-tolerant breeding. In the study, the membership function method was used to evaluate seven traits related to salt tolerance and comprehensive salt tolerance at the soybean seedling stage; genome-wide association analysis (GWAS) was performed in a natural population containing 200 soybean materials; and linkage analysis was performed in 112 recombinant inbred lines (RIL) population to detect quantitative trait loci (QTLs) of salt tolerance. In the GWAS, 147 SNPs were mapped, explaining 5.28-17.16% of phenotypic variation. In the linkage analysis, 10 QTLs were identified, which could explain 6.9-16.16% of phenotypic variation. And it was found that there were two co-located regions between the natural population and the RIL population, containing seven candidate genes of salt tolerance in soybean. In addition, one colocalization interval was found to contain qZJS-15-1, rs47665107, and rs4793412, all of which could explain more than 10% of phenotypic variation rates, making it suitable for molecular marker development. The physical positions of rs47665107 and rs47934112 were included in qZJS-15-1. Therefore, a KASP marker was designed and developed using Chr. 15:47907445, which was closely linked to the qZJS-15-1. This marker could accurately and clearly cluster the materials of salt-tolerant genotypes in the heterozygous population tested. The QTLs and KASP markers found in the study provide a theoretical and technical basis for accelerating the salt-tolerant breeding of soybean.

Physiological Phenotyping and Biochemical Characterization of Mung Bean (Vigna radiata L.) Genotypes for Salt and Drought Stress

Vigna radiata (L.) R. Wilczek, generally known as mung bean, is a crucial pulse crop in Southeast Asia that is renowned for its high nutritional value. However, its cultivation faces substantial challenges due to numerous abiotic stresses. Here, we investigate the influence of salt and drought stress on mung bean genotypes by evaluating its morpho-physiological traits and biochemical characteristics. This phenotypic analysis revealed that both salt and drought stress adversely affected mung bean, which led to reduced plant height, leaf senescence, loss of plant biomass, and premature plant death. Reactive oxygen species (ROS) production increased under these abiotic stresses. In response, to prevent damage by ROS, the plant activates defense mechanisms to scavenge ROS by producing antioxidants. This response was validated through morpho-physiological, histological, and biochemical assays that characterized KVK Puri-3 and KVK Jharsuguda-1 as salt and drought sensitive genotypes, respectively, and Pusa ratna was identified as a drought and salt tolerant genotype.

Behind the Loss of Salinity Resistance during Domestication: Alternative Eco-Physiological Strategies Are Revealed in Tomato Clade

Salinity stress impairs growth and physiological performance in tomato, which is one of the most economically important vegetables and is widely cultivated in arid and semi-arid areas of the world. Plant landraces, which are heterogeneous, local adaptations of domesticated species, offer a unique opportunity to valorize available germplasm, underpinning the productivity, resilience, and adaptive capacity of staple crops in vulnerable environments. Here, we investigated the response of fully mature tomato plants from a commercial variety, an ancestral wild relative, and a landrace under short-term salinity exposure, as well as their ability to recover upon cessation of stress. The heterogeneous panel evaluated in this study revealed different adaptative strategies to cope the stress. Our data highlighted the ability of the tomato clade to handle low and intermediate salinity stress for short-term exposure time, as well as its capacity to recover after the cessation of stress, although inter- and intraspecific variations in morphological and physiological responses to salinity were observed. Overall, the landrace and the wild type performed similarly to control conditions under low salinity, demonstrating an improved ability to maintain ionic balance. In contrast, the commercial genotype showed susceptibility and severe symptoms even under low salinity, with pronounced reductions in K+/Na+ ratio, PSII photochemical efficiency, and photosynthetic pigments. This research confirmed that improved salt tolerant genotypes can lead to substantial, positive impacts on horticultural production. While the salt tolerance mechanism of domesticated tomato was efficient under mild stress conditions, it failed at higher salinity levels.

TESTING OF WHEAT GENOTYPES FOR SALT TOLERANCE AND LEAF RUST DISEASE CAUSED BY PUCCINIA

Parameters that show a significant genotypic variation and are associated with salt tolerance may be used as rapid and economic screening criteria in breeding programs. The objective of this study was to test growth and yield components for evaluating the salt tolerance of wheat genotypes. Five genotypes of winter wheat (Triticum aestivum L.) were used in this study, that differ from their salt tolerance, which were grown in 28 dS/m saline soil, and irrigated by well water with a salinity 7.5 dS/m. The results showed that salt concentration in the soil was reduced with plant growth stages from 28 dS/m before sowing to 8, 7.5, and 7.6 dS/m for N1, N2, and N3 genotypes, respectively. Whereas approached 16 and 17 dS/m for Tumos2 and Mexipak, cultivars, respectively, at the maturity stage. Concerning germination percentage under saline conditions, wheat genotypes N1, N2, and N3 showed the highest percentages of 89, 90, and 90%, respectively, which was significantly different than wheat cultivars Tumos2 and Mexipak 79 and 83%, respectively. Statistical analysis of the data revealed that genotype N2 required a maximum days for germination 14 days, whereas cultivarTumos2 required less days for germination 12 days. For spikes formation duration growth the genotype N3 was the late 119 days, whereas for physiological maturity N1 genotype was the latest 153 days. The number of spikes per 6 m2, grains spike-1, and grain weight were reduced significantly in sensitive cultivars Tumos2 and Mexipak. Higher grain yield with N2 genotype 2739.43 g with no significant differences with the genotypes N1 and N2, and with significant differences with the rest sensitive cultivars Tumos2 and Mexipak 346.61 and 242.98 g, respectively. Therefore, we conclude that the measurements of growth and yield components may be effective criteria for screening wheat genotypes for salt tolerance. Moreover, N1, N2, and N3 genotypes were identified as the most salt-tolerant genotypes in this study, they can be utilized through appropriate selection and breeding programs for further improvement in salt tolerance of Iraqi wheat genotypes.

Effects of Salt Stress on Physiological and Agronomic Traits of Rice Genotypes with Contrasting Salt Tolerance.

Salinity is one of the major constraints to crop production. Rice is a main staple food and is highly sensitive to salinity. This study aimed to elucidate the effects of salt stress on physiological and agronomic traits of rice genotypes with contrasting salt tolerance. Six contrasting rice genotypes (DJWJ, JFX, NSIC, HKN, XD2H and HHZ), including three salt-tolerant and three salt-sensitive rice genotypes, were grown under two different salt concentrations (0 and 100 mmol L-1 NaCl solution). The results showed that growth, physiological and yield-related traits of both salt-sensitive and salt-tolerant rice were significantly affected by salt stress. In general, plant height, tiller number, dry weight and relative growth rate showed 15.7%, 11.2%, 25.2% and 24.6% more reduction in salt-sensitive rice than in salt-tolerant rice, respectively. On the contrary, antioxidant enzyme activity (superoxide dismutase, peroxidase, catalase), osmotic adjustment substances (proline, soluble protein, malondialdehyde (MDA)) and Na+ content were significantly increased under salt stress, and the increase was far higher in salt-tolerant rice except for MDA. Furthermore, grain yield and yield components significantly decreased under salt stress. Overall, the salt-sensitive rice genotypes showed a 15.3% greater reduction in grain yield, 5.1% reduction in spikelets per panicle, 7.4% reduction in grain-filling percentage and 6.1% reduction in grain weight compared to salt-tolerant genotypes under salt stress. However, a modest gap showed a decline in panicles (22.2% vs. 22.8%) and total spikelets (45.4% vs. 42.1%) between salt-sensitive and salt-tolerant rice under salinity conditions. This study revealed that the yield advantage of salt-tolerant rice was partially caused by more biomass accumulation, growth rate, strong antioxidant capacity and osmotic adjustment ability under salt stress, which contributed to more spikelets per panicle, high grain-filling percentage and grain weight. The results of this study could be helpful in understanding the physiological mechanism of contrasting rice genotypes' responses to salt stress and to the breeding of salt-tolerant rice.

Mapping Single Nucleotide Polymorphism Markers Associated with the Pre-Flowering Morphological Performance of Fenugreek under Different Levels of Salt Stress

Salinity is a significant factor restricting plant growth and production. The effect of salinity stress on different growth parameters of 111 fenugreek genotypes was examined in an experiment with three salinity levels (0, 3000, 6000 mgL−1). A completely randomized block design with two replicated pots per treatment was used. Non-significant treatment effects were observed on fresh weight (FW); however, all traits showed significant genotype-by-treatment (GxT) interactions. This GxT was reflected in substantial SNP x environment interactions. Of 492 significant SNPs associated with the measured traits, 212 SNPs were linked to the correlated traits using an arbitrary threshold of three. Several SNPs were associated with FW and dry weight, measured under the same salinity treatment. The correlation between both traits was 0.98 under the three salinity treatments. In addition, 280 SNPs with conditional neutrality effects were mapped. The identified SNPs can be used in future marker-assisted breeding programs to select salt-tolerant genotypes. The results of this research shed light on the salt-tolerant properties of fenugreek.

Differential responses of Hollyhock (Alcea rosea L.) varieties to salt stress in relation to physiological and biochemical parameters

The response of 14 Hollyhock (Alcea rosea L.) varieties to salinity were evaluated in a field experiment over two growing seasons. Carotenoid, Chl a, Chl b, total Chl, proline and MDA content, CAT, APX and GPX activity and petal and seeds yields were determined in order to investigate the mechanism of salt tolerance exhibited by Hollyhock, and too identify salt tolerant varieties. Overall, the photosynthetic pigment content,petal and seed yields were reduced by salt stress. Whereas the proline and MDA content, and the CAT, APX and GPX activities increased as salt levels increased. However, the values of the measured traits were dependent upon the on the level of salt stress, the Varietie and the interaction between the two variables. Based upon the smallest reduction in petal yield, the Masouleh variety was shown to be the most salt tolerant, when grown under severe salt stress. However, based upon the smallest reduction in seed yield, Khorrmabad was the most tolerant variety to severe salt stress. These data suggest that the selection of more salt tolerant Hollyhock genotypes may be possible based upon the wide variation in tolerance to salinity exhibited by the varieties tested.

Assessment of the salt tolerance of diverse bread wheat (Triticum aestivum L.) genotypes during the early growth stage under hydroponic culture conditions

ObjectivesSoil salinity affects the growth of crop plants, leading to reduced productivity, and is a major challenge for wheat production worldwide. Various adaptations and mitigation approaches in combination with tolerant wheat genotypes can be useful for the sustainability of crop production in saline environments. However, the development of salt-tolerant wheat genotypes is one of the best and most efficient solutions for obtaining desirable yields. Considering these issues, an investigation was carried out under hydroponic nutrient culture conditions to assess the genetic variability and selection of salt-tolerant wheat genotypes by categorizing inequitable morphophysiological and genetic variability as well as multivariate analysis. MethodsTo meet the objectives of this study, 100 wheat genotypes were tested hydroponically in 0 (control) and 15 dS m−1 salt solutions. ConclusionFor all the wheat genotypes grown under saline conditions, the shoot length (SL), root length (RL), shoot fresh weight (SFW), root fresh weight (RFW), total fresh weight (TFW), shoot dry weight (SDW), root dry weight (RDW), and total dry weight (TDW) decreased significantly. Furthermore, significant variation was observed among the genotypes in terms of their characteristics only under saline conditions. In the case of genetic diversity analysis, a high genotypic coefficient of variation (GCV), phenotypic coefficient of variation (PCV), genetic advance in the percentage of the mean (GAM) and high heritability (h2b) were recorded for all tested wheat genotypes based on the SDW, RDW and TDW. Correlation analysis for both genotypic and phenotypic relationships revealed strong positive correlations for TDW, SDW, TFW and SFW. Principal component analysis (PCA) revealed that TDW, TFW, SDW, and SFW were the most discriminative variables for the wheat genotypes, which was confirmed by discriminant function analysis (DFA). PCA-biplot analysis also revealed significant positive correlations between SDW and SFW and between TDW and TFW. Hierarchical cluster analysis was performed for ten clusters based on the relative performance of the genotypes, where the genotypes were characterized into salt-tolerant, medium-salt-tolerant, medium-salt-susceptible and salt-susceptible groups. Among the genotypes, G11, G25 and G29 under cluster VII were categorized as salt tolerant based on their outstanding performance in terms of characteristics only under saline conditions. D2 analysis proved that the wheat genotypes of this cluster were highly divergent from the other cluster genotypes; as a result, these genotypes might be utilized as parents in the development of salt-tolerant wheat genotypes. The current study concluded that SDW and TDW could be employed as criteria for selecting and defining salt-tolerant genotypes during the early growth stage of wheat.

Physiological responses, ion accumulation and yield performance of wheat (Triticum aestivum L.) to salt stress

Wheat is affected by various biotic and abiotic stresses, especially salinity, which reduces the growth and yield drastically. High salinity is a major constraint for wheat productivity in many countries, including Bangladesh. With this view, here, an experiment was conducted to observe genotypic differences in physiological, ion accumulation, agro-morphological and yield performance of wheat against different levels of salinity. Experimental variables consisted of five salt tolerant genotypes (G 20–2–2, G 20–1–2, G 13–2, G 22–2, G 9–2), one susceptible genotype (G 24–2) and one standard check variety (BARI ghom 25), which assigned to four levels of salinity with electrical conductivities control (0.3), 4, 8 and 12 dS m−1. Irrespective of genotypes, salinity stress significantly decreased the yield and yield attributes. Results of analyses based on salt tolerance indices of plant growth related and yield contributing parameters, ionic balance (Na+, K+ and Na+ /K+ ratio), and stress indicators such as chlorophyll content, photosynthetic rate (Pn), stomatal conductance (gs) and transpiration rate (Tr) revealed genotypes G 20–2–2, G 13–2 and G 20–1–2 as salt tolerant, genotype G 9–2 as moderately salt-tolerant and G 24–2 and G 22–2 as salt-sensitive genotypes. Additionally, lower accumulations of hydrogen peroxide and malondialdehyde, and higher activities of antioxidant enzymes in the salt-tolerant genotypes G 20–2–2 and G 13–2 than in the salt-sensitive genotype G 24–2 indicated reduced oxidative damage in genotypes G 20–2–2 and G 13–2 relative to that in genotype G 24–2. Collectively, our findings suggest that the optimum growth and yield of salt tolerant genotypes are associated with decreased Na+/K+ ratio, increased antioxidant enzymes activity and reduced oxidative stress.

Evaluation of Germplasm for Reproductive Stage Salinity Tolerance in Rice (Oryza sativa L.)

The current study was carried out to identify salt tolerant genotypes by screening 76 rice germplasm at reproductive stage salinity stress. The test entries were subjected to salt stress under field conditions and salinity was noted at different intervals of crop growth period i.e., 30 and 67 days after sowing and at the time of harvesting with the pH value of 5.4 and electrical conductivity of 4.3 dSm-1, 5.3 dSm-1and 7.2 dSm-1 respectively. The characters namely, salinity score, days to 50 percent flowering, plant height, panicle length, productive tillers/plant, number of filled grains/panicle, total number of grains/panicle, spikelet fertility and grain yield/plant were studied under saline conditions. Variability, heritability and genetic advance as percent of mean showed high genotypic and phenotypic coefficient of variation for grain yield plant-1indicating the presence of considerable amount of variation among the genotypes for potential yield improvement through selection. The trait grain yield per plant had high heritability coupled with high genetic advance as percent of mean indicating that it is regulated by additive gene action and therefore selection could be practiced based on phenotypic performance. Association studies under saline conditions, revealed favorable and significant correlation of grain yield per plant with days to 50% flowering, panicle length, plant height, total number of grains per panicle, number of filled grains per panicle and productive tillers per plant whereas, spikelet fertility and plant height on the other hand, recorded negative non-significant correlation, indicating the undesirable causes of salinity on plant growth and yield potential.

Salt tolerance evaluation and mini-core collection development in Miscanthus sacchariflorus and M. lutarioriparius.

Marginal lands, such as those with saline soils, have potential as alternative resources for cultivating dedicated biomass crops used in the production of renewable energy and chemicals. Optimum utilization of marginal lands can not only alleviate the competition for arable land use with primary food crops, but also contribute to bioenergy products and soil improvement. Miscanthus sacchariflorus and M. lutarioriparius are prominent perennial plants suitable for sustainable bioenergy production in saline soils. However, their responses to salt stress remain largely unexplored. In this study, we utilized 318 genotypes of M. sacchariflorus and M. lutarioriparius to assess their salt tolerance levels under 150 mM NaCl using 14 traits, and subsequently established a mini-core elite collection for salt tolerance. Our results revealed substantial variation in salt tolerance among the evaluated genotypes. Salt-tolerant genotypes exhibited significantly lower Na+ content, and K+ content was positively correlated with Na+ content. Interestingly, a few genotypes with higher Na+ levels in shoots showed improved shoot growth characteristics. This observation suggests that M. sacchariflorus and M. lutarioriparius adapt to salt stress by regulating ion homeostasis, primarily through enhanced K+ uptake, shoot Na+ exclusion, and Na+ sequestration in shoot vacuoles. To evaluate salt tolerance comprehensively, we developed an assessment value (D value) based on the membership function values of the 14 traits. We identified three highly salt-tolerant, 50 salt-tolerant, 127 moderately salt-tolerant, 117 salt-sensitive, and 21 highly salt-sensitive genotypes at the seedling stage by employing the D value. A mathematical evaluation model for salt tolerance was established for M. sacchariflorus and M. lutarioriparius at the seedling stage. Notably, the mini-core collection containing 64 genotypes developed using the Core Hunter algorithm effectively represented the overall variability of the entire collection. This mini-core collection serves as a valuable gene pool for future in-depth investigations of salt tolerance mechanisms in Miscanthus.

Investigating the genetic basis of salt-tolerance in common bean: a genome-wide association study at the early vegetative stage

Salinity poses a significant challenge to global crop productivity, affecting approximately 20% of cultivated and 33% of irrigated farmland, and this issue is on the rise. Negative impact of salinity on plant development and metabolism leads to physiological and morphological alterations mainly due to high ion concentration in tissues and the reduced water and nutrients uptake. Common bean (Phaseolus vulgaris L.), a staple food crop accounting for a substantial portion of consumed grain legumes worldwide, is highly susceptible to salt stress resulting in noticeable reduction in dry matter gain in roots and shoots even at low salt concentrations. In this study we screened a common bean panel of diversity encompassing 192 homozygous genotypes for salt tolerance at seedling stage. Phenotypic data were leveraged to identify genomic regions involved in salt stress tolerance in the species through GWAS. We detected seven significant associations between shoot dry weight and SNP markers. The candidate genes, in linkage with the regions associated to salt tolerance or harbouring the detected SNP, showed strong homology with genes known to be involved in salt tolerance in Arabidopsis. Our findings provide valuable insights onto the genetic control of salt tolerance in common bean and represent a first contribution to address the challenge of salinity-induced yield losses in this species and poses the ground to eventually breed salt tolerant common bean varieties.

A comprehensive approach for evaluating salinity stress tolerance in brinjal (Solanum melongena L.) germplasm using membership function value.

Salinity is a major stress factor affecting plant growth and development, which limits the productivity of vegetable crops. Brinjal (Solanum melongena L.), an important vegetable cultivated across the globe is susceptible to salinity stress. In the present study, the salinity tolerance response of 110 brinjal germplasm lines was evaluated at the germination stage using the membership function value (MFV). The MFV is a comprehensive index that integrates salt-tolerance indices of germination parameters. The brinjal germplasms were classified into highly salt-tolerant (>0.79), salt-tolerant (0.79-0.65), moderately salt-tolerant (0.64-0.21), salt-sensitive (0.20-0.07), and highly salt-sensitive (<0.07) based on their mean MFV. Among all the traits examined, germination percentage (0.874) and vigour index-I (0.808) were the most reliable traits for assessing salinity tolerance, showing a higher correlation with mean MFV. Furthermore, a comprehensive mathematical model was developed for evaluating the salt-tolerance of the brinjal germplasm. We validated our model by evaluating the brinjal germplasm at the seedling stage through a hydroponic experiment, and a strong positive correlation was observed between growth parameters at the germination and seedling stages. Salt-tolerant genotypes showed higher chlorophyll content, photosynthetic performance and biomass accumulation with lower canopy temperature (1.57°C) under salinity compared to susceptible genotypes (2.62°C). These findings provide valuable insights into the salinity tolerance of the brinjal germplasm, and identified potential candidates to elucidate the molecular mechanisms and develop salinity-tolerant cultivars. To our knowledge, this is the first report using a mathematical model based on MFV to evaluate the salt-tolerance of any vegetable crop.

Systematic assessment of salt tolerance based on morpho-physiological traits and genes related in inbred rice lines at the seedling stage

Abstract. Herawati R, Simarmata M, Masdar, Purwoko BS, Miswati. 2023. Systematic assessment of salt tolerance based on morpho-physiological traits and genes related in inbred rice lines at the seedling stage. Biodiversitas 24: 6256-6267. Salinity stress is an abiotic constraint that limits rice productivity. Salinity-tolerant traits are very complex and involve many genes. Therefore, it is difficult to conclude how rice plants respond to salinity stress. This study aimed to investigate the genetic potential of 19 rice genotypes for salt tolerance as well as the quantitative impacts of varying salinity stress levels on a subset of the genotypes. Salinity tolerance is identified in two stages: assessing salinity stress in nutrient solutions using 0, 5,000 (EC 7.8 dS.m-1), and 10,000 ppm (EC 15.62 dS.m-1). Gene expression analysis detected genes controlling salinity stress tolerance using two pairs of specific primers: DST (Drought Salt Tolerance) and OsAPX (ascorbate peroxidase). The results showed that all lines could survive high salinity stress up to EC 7.8 dS.m-1. Biplot is reflected in K-means grouping the 21 rice genotypes into three major groups, namely salt-sensitive (1 genotype, 4.75%), moderately salt-tolerant (2 genotypes, 9.5%), and salt-tolerant-very tolerant (18 genotypes, 85.7%). The DST and OsAPX1 genes showed both genes were expressed under salinity stress, although some lines showed smears or even did not appear at all, namely in G3 and G7. This result is consistent with the PCA analysis, where genotypes G3 and G7 are categorized as moderately tolerant. This study reveals that screening at the seedling stage combined with marker-assisted selection can identify tolerant genotypes. Furthermore, conducting field trials on soil salinity with EC &gt; 4 dS.m-1 is recommended to obtain salinity-tolerant lines as potential new varieties.

The potential application of biochar and salicylic acid to alleviate salt stress in soybean (Glycine max L.)

Salt stress has been one of the major contributor which affect soybean seed germination, its establishment, growth, and physiology stages. Utilization of strategies such as soil amendment and elicitors are of significant importance to reduce the disadvantageous effects of salt stress. In this regard, the objectives of the present study were to evaluate the effect of biochar and salicylic acid on morphological and physiological properties of soybean subjected to salinity. The first experiment was carried out based on completely randomized design with three replications including 11 soybean cultivars such as Williams, Saba, Kowsar, Tapor, Sari, Telar, Caspian, Nekador, Amir, Katol and Sahar and various levels of salinity such as 0, 2, 4, 6 dS/m of NaCl. The second experiment was performed as factorial design in a randomized complete block design with three replications consisting of treatments of biochar (0, 5 and 10 WP), salicylic acid (0, 0.5 and 1 mM), and NaCl (0, 2.5, 5, 7.5 dS/m). With respect to seed germination result, various concentrations of salt stress showed negative impact not only on all studied traits, but also varied among soybean cultivars indicating Amir cultivar as the best salt tolerant soybean genotype among others. In addition, our data exhibited that the interaction effect of biochar and salicylic acid on salt treated soybean plant were positively significant on some morphological traits such as leaf area, shoot dry/fresh weight, total dry/fresh weight and physiological attributes including chlorophyll a, flavonoid, proline contents, catalase and peroxidase activities. Moreover, the resultant data showed that the combination treatment of 5 and 10 WP of biochar and 1 mM of salicylic acid caused increase of the aforementioned parameters in order to improve their performance subjected to higher concentration of salinity. In final, it was concluded that the coupled application of biochar alongside salicylic acid was recommended as proficient strategy to mitigate the injurious influences of salt stress in soybean or other probable crops.

Comparison of expression patterns of salt tolerance-related gene HKT1;4 in bread wheat genotypes

The HKT gene family, which encodes K+ /Na+ transport proteins of cell membranes, plays a unique role in controlling plant responses to salt stress. The transcriptional activity of the HKT1;4 gene was assessed in root and leaf tissues of bread wheat genotypes (tolerant Murov 2 and sensitive Aran) that differed in salt tolerance. The HKT1;4 transcript was not found in plant leaves. A genotype-specific change in the root-specific expression of the HKT1;4 gene was observed in response to salt stress: expression of a given gene was weakened in the salt-tolerant genotype and increased in the sensitive genotype. The data could be used to improve the salt tolerance of the wheat plant. Keywords: Wheat, salinity tolerance, TaHKT1;4 gene

Comparative Transcript Profiling and Multiplex qRT-PCR Analysis Between Salt-Tolerant and Sensitive Wheat Genotypes

Identification of candidate genes combined with gene expression profiling carries importance to facilitate the molecular basis of salt stress response in plants. Here, cDNA-AFLP was used to compare the transcribed sequences among two bread and two durum wheat genotypes with different levels of salt tolerance. Transcript derived fragments (TDFs) screened on polyacrylamide gels and 36 salt stress induced unique fragments were detected in salt tolerant bread wheat genotype (Alpu cv.). The fragment size of these 36 TDFs was ranged between 99bp to 252bp. Full sequence information of 14 TDFs were obtained after cloning, then GeXP analyzer-based multiplex qRT-PCR assay was performed on leaf tissue derived from 12 TDFs. Targeted gene expression levels of two TDFs (TDF4-GT066302 and TDF11-GT066301) were showed clear upregulation in salt tolerant bread wheat genotype (Alpu cv.) and they were matched with hypothetical proteins. Especially, gene expression level of GT066301 was increased as 3.28 fold at 27th hours of salt stress for salt tolerant genotype. According to blastx similarity results, out of 14 sequenced fragments, two TDFs were closely matched with “cytochrome P450 monooxygenase” protein while four of them matched with Oryza “hypothetical” and “unknown” proteins. Outputs of this study might ensure comparative data for hypothetical protein gene expression and new useful alleles in response to salt stress in wheat.