scholarly journals Diversity of Salt Tolerance During Germination in Medicago ciliaris (L.) and Medicago polymorpha (L.)

2017 ◽  
Vol 1 (1) ◽  
pp. 6-12
Author(s):  
Chérifi Khalil ◽  
ElHoussein Boufous ◽  
Abdelhamid El Mousadik

Variability of salt tolerance in eight wild populations of two annual Medicago species (Medicago ciliaris and Medicago polymorpha) was evaluated at germination stage using tree treatments of salinity: 50, 100 and 150 mM of NaCl. Results showed that germination is clearly affected by high salt stress; their germination rate doesn’t exceed 7% at 150 mM. The greatest variability in tolerance was observed at moderate salt stress (50 mM of NaCl) and the decrease in germination seems to be more accentuated in Medicago polymorpha than Medicago ciliaris. Whereas, the Tunisian population of Medicago ciliaris was the best tolerant in all ecotypes studied in this work. This population prospected on soils affected by salinity, exhibits a particular adaptability to salt environment, at least at this stage in the life cycle. This intra-specific variation in salt tolerance may be used to select genotypes particularly suitable for cultivation on lands relatively affected by salinity. On the other hand, when ungerminated seeds from NaCl treatments were transferred to distilled water, they recovered largely their germination at all the populations studied after only 2 days. This, indicate that the germination inhibition was related to osmotic stress rather than ion toxicity. In addition, seed germination in all populations tended to be extremely rapid than that observed in distilled water which indicate that this pretreatment raises dormancy.

2020 ◽  
Vol 21 (3) ◽  
pp. 1165
Author(s):  
Jiayu Luan ◽  
Jingxiang Dong ◽  
Xin Song ◽  
Jing Jiang ◽  
Huiyu Li

Salt stress inhibits normal plant growth and development by disrupting cellular water absorption and metabolism. Therefore, understanding plant salt tolerance mechanisms should provide a theoretical basis for developing salt-resistant varieties. Here, we cloned ThTrx5 from Tamarix hispida, a salt-resistant woody shrub, and generated ThTrx5-overexpressing transgenic Arabidopsis thaliana lines. Under NaCl stress, the germination rate of overexpressing ThTrx5 lines was significantly increased relative to that of the nontransgenic line; under salt stress, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione levels and root length and fresh weight values of transgenic ThTrx5 plants were significantly greater than corresponding values for wild-type plants. Moreover, with regard to the transcriptome, comparison of differential gene expression of transgenic versus nontransgenic lines at 0 h and 3 h of salt stress exposure revealed 500 and 194 differentially expressed genes (DEGs), respectively, that were mainly functionally linked to catalytic activity and binding process. Pull-down experiments showed that ThTrx bound 2-Cys peroxiredoxin BAS1-like protein that influences stress response-associated redox, hormone signal transduction, and transcription factor functions. Therefore, this work provides important insights into ThTrx5 mechanisms that promote salt tolerance in plants.


2012 ◽  
Vol 60 (4) ◽  
pp. 345-355 ◽  
Author(s):  
M. Jamil ◽  
M. Ashraf ◽  
E. Rha

Salinity reduces plant growth and yield by affecting morphological and physiological processes. To alleviate the harmful effects of salt stress various approaches involving plant hormones are used. In this study several parameters involving the measurement of cell membrane injury were used to observe whether stress tolerance could be enhanced in Chinese cabbage (B. oleracea capitata L. Chinensis group) by soaking the seeds for 10 h in distilled water (control), or in 100, 150 or 200 mg l−1 gibberellic acid (GA3). The NaCl concentrations were 0 (control), 50, 100 and 150 mM. Seed treated with GA3 showed increased water uptake and decreased electrolyte leakage as compared to that of distilled water-primed seeds even 24 h after soaking under control conditions. Seed priming with GA3 increased the final germination and the germination rate (1/t50, where t50 is the time to 50% germination) under salt stress conditions. Seed priming also alleviated the harmful effect of salt stress on cabbage in terms of fresh and dry weights. Leaf area was higher in plants raised from seeds primed with the higher GA3 concentrations as compared with those raised from seeds treated with distilled water under control conditions (without NaCl) or at 50 mM NaCl stress. The chlorophyll content increased with the NaCl concentration, especially in plants grown from seeds primed with GA3. Plants grown from GA3-primed seeds also suffered lower cellular injury both under control conditions and under NaCl stress.


2005 ◽  
Vol 45 (4) ◽  
pp. 391 ◽  
Author(s):  
B. Zhang ◽  
B. C. Jacobs ◽  
M. O'Donnell ◽  
J. Guo

Salt tolerances of 3 cultivars, Menemen puccinellia (Puccinellia ciliata Bor), Tyrrell and Dundas [tall wheatgrass, Thinopyrum ponticum (Podp.) Z. W. Liu and R. R. C. Wang], were compared with respect to their seed germination, adaptive responses to salt and waterlogging, seedling emergence, plant growth, shoot osmolality and mineral contents in a series of salt-stress experiments. An inverse normal distribution provided good fits for the time to seed germination. Under NaCl stress, 50% of the control (distilled water) seed germination rates of Menemen, Tyrrell and Dundas were achieved in 178.8, 300.9 and 296.8 mmol/L NaCl, respectively. Fifty percent of the control seedling emergence rates of these 3 cultivars were in 92.7, 107.2 and 113.5 mmol/L NaCl, respectively. The seed germination rates of these 3 cultivars under both salt and waterlogging stress were far lower than those germinated only under salt stress at the same salt level. Seed pretreatment by soaking seed in NaCl solutions greatly increased the seed germination rate under salt stress for Menemen and under both salt stress and waterlogging for Dundas. Tyrrell and Dundas were very similar in their tolerance to salt stress, and were significantly (P<0.05) more salt tolerant than Menemen in terms of seed germination and seedling emergence rate. Both shoot height and dry matter of these 3 cultivars were not statistically different among all salt stress levels during the seedling elongation period, indicating that the established plants of these 3 cultivars were very salt tolerant. The salt tolerance mechanisms of these 3 cultivars are possibly related to their abilities to maintain high osmolality in shoots by regulating high sodium and potassium contents, and reducing calcium deficiency under salt stress.


PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7291 ◽  
Author(s):  
Lei Wang ◽  
Wenjing Yao ◽  
Yao Sun ◽  
Jiying Wang ◽  
Tingbo Jiang

The WRKY transcription factor family is one of the largest groups of transcription factor in plants, playing important roles in growth, development, and biotic and abiotic stress responses. Many WRKY genes have been cloned from a variety of plant species and their functions have been analyzed. However, the studies on WRKY transcription factors in tree species under abiotic stress are still not well characterized. To understand the effects of the WRKY gene in response to abiotic stress, mRNA abundances of 102 WRKY genes in Populus simonii × P. nigra were identified by RNA sequencing under normal and salt stress conditions. The expression of 23 WRKY genes varied remarkably, in a tissue-specific manner, under salt stress. Since the WRKY56 was one of the genes significantly induced by NaCl treatment, its cDNA fragment containing an open reading frame from P. simonii × P. nigra was then cloned and transferred into Arabidopsis using the floral dip method. Under salt stress, the transgenic Arabidopsis over-expressed the WRKY56 gene, showing an increase in fresh weight, germination rate, proline content, and peroxidase and superoxide dismutase activity, when compared with the wild type. In contrast, transgenic Arabidopsis displayed a decrease in malondialdehyde content under salt stress. Overall, these results indicated that the WRKY56 gene played an important role in regulating salt tolerance in transgenic Arabidopsis.


2018 ◽  
Vol 28 (2) ◽  
pp. 140-147 ◽  
Author(s):  
Ali El-Keblawy ◽  
Naeema Al-Shamsi ◽  
Kareem Mosa

AbstractHabitat-indifferent species that can grow well in both saline and non-saline soils offer a good opportunity for studying seed dormancy and salt tolerance during germination. Here, we assess interactive effects of maternal habitat and incubation conditions on salt tolerance during germination of the habitat-indifferent halophyte Suaeda vermiculata, a common perennial shrub of the arid Arabian deserts. Seeds collected from saline and non-saline habitats were germinated at six salinity levels (0–500 mM NaCl) and incubated at three temperatures and under two light regimes. Studied germination attributes were final germination, germination rate index (GRI) and germination recovery of non-germinated seeds when transferred to distilled water. The results showed insignificant difference in salt tolerance between seeds of the two habitat types at the lower salinities. At higher salinities (400 and 500 mM NaCl), germination of the saline habitat seeds was almost inhibited, but that of non-saline habitat seeds reached various levels depending on light and temperature. Both higher temperatures and darkness resulted in significant reductions of the final germination at the higher salinities. Seeds of the two habitats that did not germinate in the different treatments recovered their germination when transferred to distilled water, indicating that these seeds maintained their viability in saline solution and were able germinate upon the arrival of suitable conditions. Seeds of the two habitats germinated within 2 days at the lower salinities and GRI decreased with the increase in salinity level. Such reduction was obvious for seeds of the saline habitat. Recovery was faster for seeds of the saline habitats, especially for those incubated at higher salinities and in the dark. The difference in dormancy and germination attributes of seeds of the two habitat types reflects ecological adaptations for survival in salt marshes of arid deserts.


2011 ◽  
Vol 1 (1) ◽  
pp. 6-12 ◽  
Author(s):  
Chérifi Khalil ◽  
ElHoussein Boufous ◽  
Abdelhamid El Mousadik

2021 ◽  
Vol 22 (14) ◽  
pp. 7578
Author(s):  
Myeong-Hyeon Min ◽  
Thant Zin Maung ◽  
Yuan Cao ◽  
Rungnapa Phitaktansakul ◽  
Gang-Seob Lee ◽  
...  

Betaine aldehyde dehydrogenase 1 (BADH1), a paralog of the fragrance gene BADH2, is known to be associated with salt stress through the accumulation of synthesized glycine betaine (GB), which is involved in the response to abiotic stresses. Despite the unclear association between BADH1 and salt stress, we observed the responses of eight phenotypic characteristics (germination percentage (GP), germination energy (GE), germination index (GI), mean germination time (MGT), germination rate (GR), shoot length (SL), root length (RL), and total dry weight (TDW)) to salt stress during the germination stage of 475 rice accessions to investigate their association with BADH1 haplotypes. We found a total of 116 SNPs and 77 InDels in the whole BADH1 gene region, representing 39 haplotypes. Twenty-nine haplotypes representing 27 mutated alleles (two InDels and 25 SNPs) were highly (p < 0.05) associated with salt stress, including the five SNPs that have been previously reported to be associated with salt tolerance. We observed three predominant haplotypes associated with salt tolerance, Hap_2, Hap_18, and Hap_23, which were Indica specific, indicating a comparatively high number of rice accessions among the associated haplotypes. Eight plant parameters (phenotypes) also showed clear responses to salt stress, and except for MGT (mean germination time), all were positively correlated with each other. Different signatures of domestication for BADH1 were detected in cultivated rice by identifying the highest and lowest Tajima’s D values of two major cultivated ecotypes (Temperate Japonica and Indica). Our findings on these significant associations and BADH1 evolution to plant traits can be useful for future research development related to its gene expression.


2021 ◽  
Author(s):  
Qishen Gu ◽  
Huifeng Ke ◽  
Chenchen Liu ◽  
Xing Lv ◽  
Zhengwen Sun ◽  
...  

Abstract Key message Two candidate genes GhGASA1 and GhADC2 playing negative roles by modulating the GA and PA signaling pathway, respectively, were identified in a major QTL for germination under salt stress.The successful transition of a seed into a seedling is the prerequisite for plant propagation and crop yield. Germination is a vulnerable stage in a plant’s life cycle which is strongly affected by environmental conditions, such as salinity. In this study, we identified a novel stable quantitative trait locus (QTL) qRGR-A04-1 associated with relative germination rate (RGR) after treatment with salt stress based on a high-density genetic map under phytotron and filed conditions, with LOD values of 6.65-16.83 and 6.11-12.63% of phenotypic variations in all five environment tests. Two candidate genes with significantly differential expression between two parents were finally identified through RNA-seq and qRT-PCR analyses. Further functional analyses showed that GhGASA1- and GhADC2-overexpression lines were more sensitive to salt stress than wild-type in Arabidopsis through regulating the transcript levels of gibberellic acid (GA) and polyamine (PA) -related genes implicating in GA and PA biosynthesis with reducing the accumulation of GA and PA under salt stress, respectively. Virus-induced gene silencing analysis showed that TRV:GASA1 and TRV:ADC2 displayed more tolerant to salt stress by increasing the expression of GA-synthesis genes and decreasing the H2O2 content, respectively. Taken together, our results suggested that QTL qRGR-A04-1 and its harbored two genes, GhGASA1 and GhADC2, were promising candidates for salt tolerance improvement in cotton.


2021 ◽  
Vol 22 (7) ◽  
pp. 3475
Author(s):  
Yi Zhang ◽  
Jianzi Huang ◽  
Qiongzhao Hou ◽  
Yujuan Liu ◽  
Jun Wang ◽  
...  

Salt stress is a major increasing threat to global agriculture. Pongamia (Millettia pinnata), a semi-mangrove, is a good model to study the molecular mechanism of plant adaptation to the saline environment. Calcium signaling pathways play critical roles in the model plants such as Arabidopsis in responding to salt stress, but little is known about their function in Pongamia. Here, we have isolated and characterized a salt-responsive MpCML40, a calmodulin-like (CML) gene from Pongamia. MpCML40 protein has 140 amino acids and is homologous with Arabidopsis AtCML40. MpCML40 contains four EF-hand motifs and a bipartite NLS (Nuclear Localization Signal) and localizes both at the plasma membrane and in the nucleus. MpCML40 was highly induced after salt treatment, especially in Pongamia roots. Heterologous expression of MpCML40 in yeast cells improved their salt tolerance. The 35S::MpCML40 transgenic Arabidopsis highly enhanced seed germination rate and root length under salt and osmotic stresses. The transgenic plants had a higher level of proline and a lower level of MDA (malondialdehyde) under normal and stress conditions, which suggested that heterologous expression of MpCML40 contributed to proline accumulation to improve salt tolerance and protect plants from the ROS (reactive oxygen species) destructive effects. Furthermore, we did not observe any measurable discrepancies in the development and growth between the transgenic plants and wild-type plants under normal growth conditions. Our results suggest that MpCML40 is an important positive regulator in response to salt stress and of potential application in producing salt-tolerant crops.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Mohammad Nauman Khan ◽  
Yanhui Li ◽  
Zaid Khan ◽  
Linlin Chen ◽  
Jiahao Liu ◽  
...  

Abstract Background Salinity is a big threat to agriculture by limiting crop production. Nanopriming (seed priming with nanomaterials) is an emerged approach to improve plant stress tolerance; however, our knowledge about the underlying mechanisms is limited. Results Herein, we used cerium oxide nanoparticles (nanoceria) to prime rapeseeds and investigated the possible mechanisms behind nanoceria improved rapeseed salt tolerance. We synthesized and characterized polyacrylic acid coated nanoceria (PNC, 8.5 ± 0.2 nm, −43.3 ± 6.3 mV) and monitored its distribution in different tissues of the seed during the imbibition period (1, 3, 8 h priming). Our results showed that compared with the no nanoparticle control, PNC nanopriming improved germination rate (12%) and biomass (41%) in rapeseeds (Brassica napus) under salt stress (200 mM NaCl). During the priming hours, PNC were located mostly in the seed coat, nevertheless the intensity of PNC in cotyledon and radicle was increased alongside with the increase of priming hours. During the priming hours, the amount of the absorbed water (52%, 14%, 12% increase at 1, 3, 8 h priming, respectively) and the activities of α-amylase were significantly higher (175%, 309%, 295% increase at 1, 3, 8 h priming, respectively) in PNC treatment than the control. PNC primed rapeseeds showed significantly lower content of MDA, H2O2, and •O2− in both shoot and root than the control under salt stress. Also, under salt stress, PNC nanopriming enabled significantly higher K+ retention (29%) and significantly lower Na+ accumulation (18.5%) and Na+/K+ ratio (37%) than the control. Conclusions Our results suggested that besides the more absorbed water and higher α-amylase activities, PNC nanopriming improves salt tolerance in rapeseeds through alleviating oxidative damage and maintaining Na+/K+ ratio. It adds more knowledge regarding the mechanisms underlying nanopriming improved plant salt tolerance. Graphical abstract


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