The GmXTH1 Gene Improves Drought Stress Resistance of Soybean Seedlings

Author(s):  
Ye Zhang ◽  
Han-zhu Zhang ◽  
Jia-yu Fu ◽  
Ye-yao Du ◽  
Jing Qu ◽  
...  

Abstract To study the role of GmXTH1 gene in alleviating drought stress. T4 transgenic soybean seeds with GmXTH1 gene were treated with PEG6000 at 0%, 5%, 10% and 15%, respectively. Germination potential, germination rate and germination index were measured. The results showed that the germination potential, germination rate and germination index of OEA1 and OEA2 strains overexpressed in T4 generation were significantly higher than that of control material M18. After 0d, 7d and 15d drought stress, the analysis of seedling phenotypes and root-shoot of different T4 generation transgenic soybean lines showed that under stress conditions, the growth of GmXTH1 overexpression material was generally better than that of control material M18, and the growth of GmXTH1 interference expression material was generally worse than that of control material M18, with significant differences in plant phenotypes.The root system of GmXTH1 overexpressed material was significantly developed compared with that of control material M18. The analysis of physiological and biochemical indexes showed that the relative water content and the activity of antioxidant enzymes (superoxide dismutase and peroxidase) of GmXTH1 transgenic soybean material were significantly higher than that of control material M18, and the accumulation of malondialdehyde was lower under the same stress conditions at seedling stage. Fluorescence quantitative PCR assay showed that the relative expression of GmXTH1 gene in transgenic soybean was significantly increased after drought stress.The results showed that the overexpression of GmXTH1 could increase the total root length, surface area, total projection area, root volume, average diameter, total cross number and total root tip number, thereby increasing the water intake and reducing the transpiration of water content in leaves, thus reducing the accumulation of MDA and producing more protective enzymes in a more effective and prompt way.Reducing cell membrane damage to improve drought resistance of soybean.

Genetika ◽  
2012 ◽  
Vol 44 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Ahmad Golparvar

Mode of gene action, heritability and determination of the effective breeding strategy for improvement of physiological and traits specifically in drought stress conditions is very important. Therefore, this study was conducted by using two drought susceptible and tolerant wheat cultivars. Cultivars Sakha8 (tolerant) and Pishtaz (susceptible) as parents along with F1, F2, BC1 and BC2 generations were sown in a randomized complete block design with three replications in drought stress conditions. Results of analysis of variance indicated significant difference between generations as well as degree of dominance revealed over-dominance for the both traits. Fitting simple additive-dominance model designated that this model was not able to account for changes of traits relative water content and mean of grain filling rate. It was revealed that m-d-h-i-j model for relative water content and m-d-h-i model for mean of grain filling rate are the best models. Estimation of heritability and mode of gene action indicated that selection for improvement of traits studied in stress condition and specifically in early generations have medium genetic gain. In conclusion, grain filling rate is better than relative water content as indirect selection criteria to improve plant grain yield in drought stress condition.


Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 830 ◽  
Author(s):  
Yan Liu ◽  
Xiaoli Wei

Dark septate endophytes (DSEs) are known to help host plants survive drought stress; however, how DSEs enhance host plant drought resistance under water stress conditions remains unclear. The objective of this study was to inoculate Ormosia hosiei seedlings with a DSE strain (Acrocalymma vagum) to investigate the effects of DSE inoculation on root morphology, ultrastructure, and the endogenous hormone content under drought stress conditions and to elucidate the drought resistance mechanism involved in the DSE–host-plant association. The inoculated seedlings were grown under three different soil water conditions (well watered—75% field water capacity, moderate water—55% field water capacity, or low water—35% field water capacity) for 114 days. Fresh root weight, root volume, root surface area, root fork, and root tip number were significantly higher in inoculated seedlings than in noninoculated seedlings. Furthermore, the root architecture of the inoculated seedlings changed from herringbone branching to dichotomous branching. Mitochondria and other organelles in root cells of inoculated seedlings remained largely undamaged under water stress, whereas organelles in root cells of noninoculated seedlings were severely damaged. The abscisic acid (ABA) and indole-3-acetic acid (IAA) content and IAA/ABA ratio of inoculated seedlings were significantly higher than those of noninoculated seedlings, whereas the content of gibberellic acid (GA) and the ratios of GA/ABA, zeatin riboside (ZR)/ABA, and ZR/IAA in inoculated seedlings were lower than those of noninoculated seedlings. DSE inoculation could help plants adapt to a drought stress environment by altering root morphology, reducing ultrastructural damage, and influencing the balance of endogenous hormones, which could be of great significance for the cultivation and preservation of the O. hosiei tree.


2018 ◽  
Vol 2 (2) ◽  
pp. 39-45
Author(s):  
ABDELHAKIM HATIMI ◽  
SAIDIA TAHROUCH ◽  
BRAHIM BOUIZGARNE

Hatimi A, Tahrouch S, Bouizgarne B. 2018. Effect of symbiotic association of rhizobia and endomycorrhizae from Moroccan arid littoral dunes on Acacia cyanophylla tolerance to drought. Asian J For 2: 39-45. The research on behavior of A. cyanophylla Lindl plants associated with a symbiotic indigenous endomycorrhizal fungi M, and three rhizobia isolates: two low growing isolate R1 (Bradyrhizobium sp. RCM6), and R2 (Bradyrhizobium sp. RLC3) and a fast-growing isolates R3 (Rhizobium sp. S21), originated from coastal dunes of the Souss-Massa region in drought stress conditions, was investigated in greenhouse. Results have clearly shown that the growth and nutrition of seedlings of A. cyanophylla were drastically affected after two months in drought stress conditions. However, inoculation of the symbiotic microorganisms either alone (treatments M, RMC6, R2 or R3) or as inoculums consisting of combination of the rhizobia with the endomycorrhiza (treatments MR1, MR2 or MR3) resulted in enhanced tolerance of A. cyanophylla seedlings to drought stress. At 100% of field capacity (fc), all treatments showed a significant improvement of plant growth compared to non-inoculated plants in stress conditions. In addition, we have shown that Bradyrhizobium RCM6 (R1) holds a high efficiency to improve the growth and nutrition of the host plant. Indeed, higher number of nodules/plant and higher amount of total nitrogen were recorded in the seedlings inoculated with Bradyrhizobium sp. RCM6 in comparison with plants inoculated with the two other rhizobia Bradyrhizobium sp. RLC3 (R2) and Rhizobium sp. S21 (R3), and control plants. Dual inoculation with each of the three rhizobia and the endomycorrhizal complex (M) led to higher water content (W.C) and relative water content (RWC) and a significant increase in Phosphorus content of the aerial part. While positive effects were recorded for Phosphorus, no such effects were recorded for nitrogen. However, the overall results showed the importance of the use of microorganisms in the dune coastal environment particularly adequate tripartite association: rhizobia Endomycorrhizes-A. cyanophylla in enhancing tolerance to drought stress.


2019 ◽  
Vol 1 (2) ◽  
Author(s):  
Yongji Wang

To explore the optimum temperature, light intensityand water conditions for seed germination of Siphonostegia chinensis Benth.,seed germination experiment were carried out under different temperatures(5/15, 10/20, 15/25, 20/30℃), different light intensity(14h light/10h darkness, complete darkness)and different concentrations(0%, 5%, 10%, 15%, 20%)of PEG-6000 solution. In terms of concentration, 5% PEG was regarded as the low level, 10% and 15% as the medium level, and 20% as the high level. The results showed that (1) Germination rate, germination potential, and germination index were increased with the rise of temperature. In addition, seed germination was significantly higher under the dark conditions than that with the 14h light/10h darkness. (2) No seed germination occurred when the temperature was below 10/20 ºC at 14h light/10h darkness. (3) Under 14h light/10h darkness, the germination rate, germination potential and germination index first increased and then decreased with the increase of PEG concentration. The low concentration was more beneficial to the seed germination. (4) Under the condition of complete darkness, the germination rate, germination potential and germination index decline with fluctuation with the increase of PEG concentration. Seed germination of Siphonostegia chinensis Benth. was inhibited in high concentration of PEG.


2021 ◽  
Author(s):  
Shabnam Gohari ◽  
Ali Imani ◽  
AliReza Talaei ◽  
Vahid Abdossi ◽  
Mohamad Reza Asghari

Abstract Background Almonds ( Prunus amygdalus Batsch, syn. P. dulcis (Mill.) DA Webb) is a valuable nut crops species that is widely is cultivated in arid and semi-arid regions of Iran, due to drought tolerance and dehydration under drought stress. Almonds show physiological adaptations for survival in drought stress conditions, but the degree Drought adaptation varies between cultivars. However, to date, its morphological and physiological responses to drought, and the underlying mechanisms are not well understood. This study was aimed to investigate the morphological and physiological changes of almond genotypes under drought stress. almond genotypes were planted in pots and subjected to four levels of soil water treatments: above 80% (control), 60% (light stress), and 40% (severe stress) of field capacity. Results Within the total stress period (0–30 days), almond genotypes grew rapidly in the light stress, whereas severe stress had a negative impact on growth. So that, in this study, 10 selected almond genotypes using some morphological traits such as: plant height, trunk diameter at the top of the graft, new branch growth length, leaf yellowness and some physiological indicators under drought stress conditions such as Chlorophyll index was evaluated based on SPAD criterion, relative leaf water content, measurement of chlorophyll fluorescence and Organic Osmoprotectants to identify drought-resistant and sensitive genotypes under drought stress conditions. Among the selected genotypes studied, genotype A-7-100 was the most resistant and genotype A-124-1 was the most sensitive to drought stress. Conclusions Our results show that almond genotypes adapt to drought mainly by avoidance mechanisms, and its morphological and physiological characteristics are inhibited under severe stress, However, the degree of drought adaptation varies between different cultivars. These findings might help limited water resources to be fully used for increased the percentage of kernel and finally increased the growth and yield of plants under water stress.


Author(s):  
Yufeng Xu ◽  
Miao Liu ◽  
Yuanhao Lv ◽  
Qiuli Wang ◽  
Bo Qu ◽  
...  

Aims: Global warming and biological invasion are major environmental issues faced in the world. In the study, Rorippa amphibia, a perennial invasive clone plant in northern China, was used as a material to study the germination characteristics of the seeds at different temperatures. Study Design: Germination test of R. amphibia seeds at different temperature was studied by means of laboratory culture. The germination percentage, germination index, germination potential, bud height and root length of the seeds were determined. Place and Duration of Study: Samples were collected from the west side of the swimming pool of Shenyang Agricultural University of Liaoning Province in August 2017. Experiments were done in the College of Biological Science and Technology, between October 2017 and June 2018. Methodology: The petri dish method was used in the experiment. Fifty seeds were randomly selected and soaked in distilled water for 12h. The seeds were placed in a petri dish covered with double filter paper, cultured at 10℃, 15℃, 20℃, 25℃, 30℃, 35℃ and 40℃ in light incubators for 12h darkness and 12h light (4000lux), with 3 repeats per processing. Seed germination was based on embryo root breakthrough seed coat ≥ 1 mm. During the experiment, the numbers of seed germination were recorded every day, and the filter paper was kept moist until there was no new seed germination for 2 consecutive days, which was regarded as the end of germination. The numbers of seed germination should be counted regularly every day, and the beginning and duration of germination should be recorded. The germination rate, daily germination rate, germinating potential, germinating index and vigor index of R. amphibia seeds at different temperature were calculated by measuring bud height and radicle length on the 10th day after germination. Results: The temperature range of seed germination of R. amphibia was wide, which could germinate at 15 - 40℃. Lower temperature delayed the peak period of seed germination at some extent and the germination rates of R. amphibia peak at 30 - 35℃, which were 44.67% and 50% respectively. At 35℃, germination potential and germination index were 25.33% and 29.46, reaching the maximum value. Conclusion: The reason for the wide temperature range of seed germination and the low germination rate might be the candidate method for clonal plant population establishment in temperate zone. The higher germination rate of high temperature condition suggested that clone invasive plants in temperate regions were more invasive during global warming.


Author(s):  
Thi Thanh Nhan Pham ◽  
Huu Quan Nguyen ◽  
Thi Ngoc Lan Nguyen ◽  
Xuan Tan Dao ◽  
Danh Thuong Sy ◽  
...  

The dehydration responsive element binding (DREB) is a plant protein subfamily expressed when soybean plants face abiotic stresses. These DREB proteins are also considered to activate the transcription of drought-resistant genes. In this study, we present the determined results of relationships between overexpression of Glycine max DREB2 (GmDREB2) with the transcription level of Glycine max pyrroline-5-carboxylate synthetase (GmP5CS) gene, proline accumulation and drought tolerant ability transgenic soybean plants as the basis for selection of transgenic lines with high drought tolerance. GmDREB2 was inserted into a plant transgenic vector and the 35S-GmDREB2-cmyc construct was transferred into the soybean plants by Agrobacterium-mediated transformation. Recombinant GmDREB2 protein with a molecular weight of approximately 20 kDa was expressed in four transgenic soybean lines in the T1 generation. The GmP5CS gene was shown to have significantly (P<0.05) increased expression in the T2 transgenic soybean lines and higher than compared to non-transgenic plants with considering both in well watered condition and stressed conditions were from 1.06 to 1.31-fold and 1.37 to 1.95-fold, respectively. The proline content of four transgenic soybean lines increased 155.81% to 187.42 % after five days in drought-stress conditions and increased from 180.52 % to 233.74 % after nine days under drought-stress conditions (P<0.05). Therefore, the overexpression of GmDREB2 resulted in increasing transcription level of P5CS gene, proline accumulation and drought-stress tolerance of the transgenic soybean plants. The GmDREB2 transformation into soybean plants was confirmed by the results of genetically modified lines in the T2 generation (T2-1, T2-6, T2-7, and T2-8) with higher drought tolerant ability than those of non-transgenic plants.


2019 ◽  
Vol 63 (1) ◽  
pp. 314-322
Author(s):  
C.G. Goncalves ◽  
A.C. Silva ◽  
L.R. Alves ◽  
M.R.R. Pereira ◽  
P.L. Gratao ◽  
...  

2014 ◽  
Vol 955-959 ◽  
pp. 208-212 ◽  
Author(s):  
Yan Zhao ◽  
Qing Song Yang ◽  
Shu Yang ◽  
Hong Mei Zhao ◽  
Qing Song Duan ◽  
...  

In order to study the effect of seed soaking with biogas slurry on seed germination and growth of faba beans (Vicia faba L.), the experiment was conducted. The seeds were soaked in biogas slurry for various soaking durations (0, 2, 4, 6 and 8 hours) and different concentration (0, 25, 50, 75 and 100 %) along with control to determine the optimal soaking duration and find out the best growing condition. The highest germination rate, germination potential and germination index were obtained when the faba beans seeds soaked for 4 hours in 75 % biogas slurry. Seedling growth was recorded in plants where seeds soaked for 6 hours in 75 % biogas slurry. It was concluded that the seed soaking of biogas slurry with lower concentration (25, 50 and 75 %) showed best results regarding maximum germination and enhanced growth. However, under the higher concentration (100 %) conditions of biogas slurry had a tendency of decrease on seed germination and seedling growth.


2006 ◽  
Vol 131 (2) ◽  
pp. 295-301 ◽  
Author(s):  
William L. Bauerle ◽  
William W. Inman ◽  
Jerry B. Dudley

Quantitative differences in leaf abscisic acid (ABAL) among four cultivars of red maple (Acer rubrum L.) and one freeman maple (Acer ×freemanii E. Murray) cultivar were investigated. This study tested the hypothesis that ABAL concentration can be used to compare the effects of water stress on the gas exchange response of five different maple genotypes, including four red maple cultivars [`Summer Red', `October Glory', `Autumn Flame', and `Franksred' ('Red Sunset')] and one hybridized freeman maple cultivar ['Jeffersred' ('Autumn Blaze')]. Two-year-old cloned genotypes of red maple and freeman maple were subjected to two treatments: irrigated daily to container capacity or irrigation withheld for one drought and recovery cycle. Leaf abscisic acid concentration, gas exchange, and wholetree sap flow measurements were conducted under well-watered and drought stress conditions. Over the course of the drought stress and recovery phase, net photosynthesis (Anet), stomatal conductance (gs), and transpiration (E) declined as ABAL and instantaneous water use efficiency (A/gs) increased. Until severe water stress conditions were prominent, water use was higher in `Summer Red' as compared to `October Glory'. This study found that ABAL tracked gs and that stomatal responsiveness to substrate moisture deficit is likely mediated by ABA accumulation in leaf tissue. This research demonstrates a leaf level physiological response to substrate volumetric water content that appears to depend on ABAL concentration. In addition, the evidence in this study indicates that ABAL may be used as a potential surrogate for the gs response to substrate water stress and could become part of a cultivar drought tolerance selection strategy for red maple and freeman maple.


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