Exogenous Melatonin Modulates the Physiological and Biochemical Mechanisms of Drought Tolerance in Tartary Buckwheat (Fagopyrum tataricum (L.) Gaertn)

Tartary buckwheat is one of the nutritious minor cereals and is grown in high-cold mountainous areas of arid and semi-arid zones where drought is a common phenomenon, potentially reducing the growth and yield. Melatonin, which is an amphiphilic low molecular weight compound, has been proven to exert significant effects in plants, under abiotic stresses, but its role in the Tartary buckwheat under drought stress remains unexplored. We evaluated the influence of melatonin supplementation on plant morphology and different physiological activities, to enhance tolerance to posed drought stress by scavenging reactive oxygen species (ROS) and alleviating lipid peroxidation. Drought stress decreased the plant growth and biomass production compared to the control. Drought also decreased Chl a, b, and the Fv/Fm ratio by 54%, 70%, and 8%, respectively, which was associated with the disorganized stomatal properties. Under drought stress, H2O2, O2•−, and malondialdehyde (MDA) contents increased by 2.30, 2.43, and 2.22-folds, respectively, which caused oxidative stress. In contrast, proline and soluble sugar content were increased by 84% and 39%, respectively. However, exogenous melatonin (100 µM) could improve plant growth by preventing ROS-induced oxidative damage by increasing photosynthesis, enzymatic antioxidants (superoxide dismutase, peroxidase, catalase, and ascorbate peroxidase), secondary metabolites like phenylalanine ammonialyase, phenolics, and flavonoids, total antioxidant scavenging (free radical DPPH scavenging), and maintaining relative water content and osmoregulation substances under water stress. Therefore, our study suggested that exogenous melatonin could accelerate drought resistance by enhancing photosynthesis and antioxidant defense in Tartary buckwheat plants.

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Nucleoredoxin Gene TaNRX1 Positively Regulates Drought Tolerance in Transgenic Wheat (Triticum aestivum L.)

Frontiers in Plant Science ◽

10.3389/fpls.2021.756338 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yunrui Zhang ◽

Jianfei Zhou ◽

Fan Wei ◽

Tianqi Song ◽

Yang Yu ◽

...

Keyword(s):

Triticum Aestivum ◽

Drought Stress ◽

Stress Tolerance ◽

Sugar Content ◽

Soluble Sugar ◽

Triticum Aestivum L ◽

Growth And Yield ◽

Regulation Mechanism ◽

Drought Stress Tolerance ◽

Relative Electrical Conductivity

Drought is the main abiotic stress factor limiting the growth and yield of wheat (Triticum aestivum L.). Therefore, improving wheat tolerance to drought stress is essential for maintaining yield. Previous studies have reported on the important role of TaNRX1 in conferring drought stress tolerance. Therefore, to elucidate the regulation mechanism by which TaNRX1 confers drought resistance in wheat, we generated TaNRX1 overexpression (OE) and RNA interference (RNAi) wheat lines. The results showed that the tolerance of the OE lines to drought stress were significantly enhanced. The survival rate, leaf chlorophyll, proline, soluble sugar content, and activities of the antioxidant enzymes (catalase, superoxide dismutase, and peroxidase) of the OE lines were higher than those of the wild type (WT); however, the relative electrical conductivity and malondialdehyde, hydrogen peroxide, and superoxide anion levels of the OE lines were lower than those of the WT; the RNAi lines showed the opposite results. RNA-seq results showed that the common differentially expressed genes of TaNRX1 OE and RNAi lines, before and after drought stress, were mainly distributed in the plant–pathogen interaction, plant hormone signal transduction, phenylpropane biosynthesis, starch and sucrose metabolism, and carbon metabolism pathways and were related to the transcription factors, including WRKY, MYB, and bHLH families. This study suggests that TaNRX1 positively regulates drought stress tolerance in wheat.

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Influence of heat stress on leaf morphology and nitrogen–carbohydrate metabolisms in two wucai (Brassica campestris L.) genotypes

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.3554 ◽

2017 ◽

Vol 86 (2) ◽

Cited By ~ 8

Author(s):

Lingyun Yuan ◽

Ling Tang ◽

Shidong Zhu ◽

Jinfeng Hou ◽

Guohu Chen ◽

...

Keyword(s):

Heat Stress ◽

Plant Growth ◽

Leaf Morphology ◽

Nitrogen Assimilation ◽

Sugar Content ◽

Soluble Sugar ◽

Physiological Mechanism ◽

Growth And Yield ◽

Metabolic Enzyme ◽

Heat Tolerant

Heat stress is a major environmental stress that limits plant growth and yield worldwide. The present study was carried out to explore the physiological mechanism of heat tolerant to provide the theoretical basis for heat-tolerant breeding. The changes of leaf morphology, anatomy, nitrogen assimilation, and carbohydrate metabolism in two wucai genotypes (WS-1, heat tolerant; WS-6, heat sensitive) grown under heat stress (40°C/30°C) for 7 days were investigated. Our results showed that heat stress hampered the plant growth and biomass accumulation in certain extent in WS-1 and WS-6. However, the inhibition extent of WS-1 was significantly smaller than WS-6. Thickness of leaf lamina, upper epidermis, and palisade mesophyll were increased by heat in WS-1, which might be contributed to the higher assimilation of photosynthates. During nitrogen assimilation, WS-1 possessed the higher nitrogen-related metabolic enzyme activities, including nitrate reductase (NR), glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH), which were reflected by higher photosynthetic nitrogen-use efficiency (PNUE) with respect to WS-6. The total amino acids level had no influence in WS-1, whereas it was reduced in WS-6 by heat. And the proline contents of both wucai genotypes were all increased to respond the heat stress. Additionally, among all treatments, the total soluble sugar content of WS-1 by heat got the highest level, including higher contents of sucrose, fructose, and starch than those of WS-6. Moreover, the metabolism efficiency of sucrose to starch in WS-1 was greater than WS-6 under heat stress, proved by higher activities of sucrose phosphate synthase (SPS), sucrose synthase (SuSy), acid invertase (AI), and amylase. These results demonstrated that leaf anatomical alterations resulted in higher nitrogen and carbon assimilation in heat-tolerant genotype WS-1, which exhibited a greater performance to resist heat stress.

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Morphological, Physiological and Biochemical Responses of Poplar Plants to Drought Stress

Journal of AgriSearch ◽

10.21921/jas.5.3.7 ◽

2018 ◽

Vol 5 (03) ◽

Author(s):

ARADHNA KUMARI ◽

IM KHAN ◽

ANIL KUMAR SINGH ◽

SANTOSH KUMAR SINGH

Keyword(s):

Water Stress ◽

Drought Stress ◽

Biochemical Parameters ◽

Sugar Content ◽

Soluble Sugar ◽

Field Capacity ◽

Drought Event ◽

Total Biomass ◽

Biochemical Responses ◽

Physiological And Biochemical

Poplar clone Kranti was selected to assess the morphological, physiological and biochemical responses under drought at different levels of water stress, as it is a common clone used to be grown in Uttarakhand for making paper and plywood. The cuttings of Populus deltoides L. (clone Kranti) were exposed to four different watering regimes (100, 75, 50 and 25% of the field capacity) and changes in physiological and biochemical parameters related with drought tolerance were recorded. Alterations in physiological (i.e. decrease in relative water content) and biochemical parameters (i.e. increase in proline and soluble sugar content and build-up of malondialdehyde by-products) occurred in all the three levels of water stress, although drought represented the major determinant. Drought treatments (75%, 50% and 25% FC) decreased plant height, radial stem diameter, harvest index, total biomass content and RWC in all the three watering regimes compared to control (100% FC). Biochemical parameters like proline, soluble sugar and MDA content increased with severity and duration of stress, which helped plants to survive under severe stress. It was analyzed that for better wood yield poplar seedlings should avail either optimum amount of water (amount nearly equal to field capacity of soil) or maximum withdrawal up to 75% of field capacity up to seedling establishment period (60 days). Furthermore, this study manifested that acclimation to drought stress is related with the rapidity, severity, and duration of the drought event of the poplar species.

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ACC Deaminase Producing PGPR Bacillus amyloliquefaciens and Agrobacterium fabrum along with Biochar Improve Wheat Productivity under Drought Stress

Agronomy ◽

10.3390/agronomy9070343 ◽

2019 ◽

Vol 9 (7) ◽

pp. 343 ◽

Cited By ~ 21

Author(s):

Muhammad Zafar-ul-Hye ◽

Subhan Danish ◽

Mazhar Abbas ◽

Maqshoof Ahmad ◽

Tariq Muhammad Munir

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Grain Yield ◽

Bacillus Amyloliquefaciens ◽

Nutrient Retention ◽

Acc Deaminase ◽

Growth And Yield ◽

Yield Traits ◽

Straw Yield ◽

Soil Application

Drought stress retards wheat plant’s vegetative growth and physiological processes and results in low productivity. A stressed plant synthesizes ethylene which inhibits root elongation; however, the enzyme 1-Aminocyclopropane-1-Carboxylate (ACC) deaminase catabolizes ethylene produced under water stress. Therefore, the ACC deaminase producing plant growth promoting rhizobacteria (PGPR) can be used to enhance crop productivity under drought stress. Biochar (BC) is an organically active and potentially nutrient-rich amendment that, when applied to the soil, can increase pore volume, cation exchange capacity and nutrient retention and bioavailability. We conducted a field experiment to study the effect of drought tolerant, ACC deaminase producing PGPR (with and without timber waste BC) on plant growth and yield parameters under drought stress. Two PGPR strains, Agrobacterium fabrum or Bacillus amyloliquefaciens were applied individually and in combination with 30 Mg ha−1 BC under three levels of irrigation, i.e., recommended four irrigations (4I), three irrigations (3I) and two irrigations (2I). Combined application of B. amyloliquefaciens and 30 Mg ha−1 BC under 3I, significantly increased growth and yield traits of wheat: grain yield (36%), straw yield (50%), biological yield (40%). The same soil application under 2I resulted in greater increases in several of the growth and yield traits: grain yield (77%), straw yield (75%), above- and below-ground biomasses (77%), as compared to control; however, no significant increases in chlorophyll a, b or total, and photosynthetic rate and stomatal conductance in response to individual inoculation of a PGPR strain (without BC) were observed. Therefore, we suggest that the combined soil application of B. amyloliquefaciens and BC more effectively mitigates drought stress and improves wheat productivity as compared to any of the individual soil applications tested in this study.

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Fungal Endophytes Promote Tomato Growth and Enhance Drought and Salt Tolerance

Plants ◽

10.3390/plants9070877 ◽

2020 ◽

Vol 9 (7) ◽

pp. 877

Author(s):

Mustafa Morsy ◽

Blake Cleckler ◽

Hayden Armuelles-Millican

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Crop Production ◽

Fungal Endophytes ◽

Fruit Yield ◽

Growth And Yield ◽

Wild Plants ◽

Penicillium Sp ◽

Drought And Salt Tolerance ◽

Tomato Growth

In a search for efficient fungal endophytes that can promote crop production and/or increase crop tolerance to abiotic stress, we isolated and tested various species harbored by wild plants. Sixty-seven endophytic fungal isolates were obtained from drought stressed, poor soil habitats, and inland high salt areas. We extensively tested the roles of Ampelomyces sp. and Penicillium sp. isolates in improving tomato growth and yield. Under greenhouse and field trails, Ampelomyces sp. and Penicillium sp. endophytes proved effective in conferring positive benefits to tomatoes placed under stress as well as under normal growing conditions. Ampelomyces sp. conferred tolerance to tomatoes placed under drought stress in addition to enhancing overall plant growth and fruit yield in comparison to non-symbiotic plants under drought stress. Penicillium sp. conferred tolerance to tomatoes placed under 300 mM salinity stress in addition to enhancing root biomass in comparison to non-symbiotic plants. Both endophytes proved efficient in enhancing plant growth, stress tolerance, recovery, and fruit yield under optimal experimental conditions in comparison to non-symbiotic plants. Field testing of tomato yield showed increased yield of symbiotic tomatoes compared to non-symbiotic ones. This data suggests that both Ampelomyces sp. and Penicillium sp. share a promising potential for improving future agricultural production, particularly with the projected changes in climate in the future.

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Microbial Diversity of Upland Rice Roots and Their Influence on Rice Growth and Drought Tolerance

Microorganisms ◽

10.3390/microorganisms8091329 ◽

2020 ◽

Vol 8 (9) ◽

pp. 1329

Author(s):

Zhiqiang Pang ◽

Ying Zhao ◽

Peng Xu ◽

Diqiu Yu

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Upland Rice ◽

Oryza Sativa L ◽

Soluble Sugar ◽

Stress Conditions ◽

Rice Roots ◽

Microbial Resources

Among abiotic stresses, drought is one of the most important factors limiting plant growth. To increase their drought tolerance and survival, most plants interact directly with a variety of microbes. Upland rice (Oryza sativa L.) is a rice ecotype that differs from irrigated ecotype rice; it is adapted to both drought-stress and aerobic conditions. However, its root microbial resources have not been explored. We isolated bacteria and fungi from roots of upland rice in Xishuangbanna, China. Four hundred sixty-two endophytic and rhizospheric isolates (337 bacteria and 125 fungi) were distributed. They were distributed among 43 genera on the basis of 16S rRNA and internal transcribed spacer (ITS) gene sequence analysis. Notably, these root microbes differed from irrigated rice root microbes in irrigated environments; for example, members of the Firmicutes phylum were enriched (by 28.54%) in the roots of the upland plants. The plant growth-promoting (PGP) potential of 217 isolates was investigated in vitro. The PGP ability of 17 endophytic and 10 rhizospheric isolates from upland rice roots was evaluated under well-irrigated and drought-stress conditions, and 9 fungal strains increased rice seedling shoot length, shoot and root fresh weight (FW), antioxidant capability, and proline (Pro) and soluble sugar contents. Our work suggests that fungi from upland rice roots can increase plant growth under irrigated and drought-stress conditions and can serve as effective microbial resources for sustainable agricultural production in arid regions.

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Supportive effect of naringenin on NaCl-induced toxicity in Carthamus tinctorius seedlings

10.21203/rs.3.rs-1050672/v1 ◽

2021 ◽

Author(s):

Shahab Hatamipoor ◽

Leila Shabani ◽

Sadegh Farhadian

Keyword(s):

Phenolic Compound ◽

Salinity Stress ◽

Plant Biomass ◽

Sugar Content ◽

Soluble Sugar ◽

Total Phenolic ◽

Enzymatic Antioxidants ◽

Total Phenolic Compound ◽

Mda Content ◽

Pre Treatment

Abstract Background The exogenous application of priming molecules to plants helps them to develop tolerance against salinity stress. In the present study, we used exogenous naringenin (0.5 mM) pretreatment before the stress in safflower seedlings under 25 mM NaCl to elucidate the role of naringenin to alleviate oxidative conditions associated with salinity complications. Results Our results showed biomass, leaf relative water content, chlorophyll content, K+ content, and K+/Na+ ratio were negatively affected by 25 mM NaCl. However, the H2O2 accumulation, malondialdehyde (MDA) content, antioxidant enzymes and Na+ content of NaCl-stressed safflower seedlings were remarkably increased. The results obtained in the present study showed the beneficial effects of the pre-treatment of naringenin in safflower seedlings under non-salinity stress condition with respect to increasing plant biomass, total phenolic compound, radical scavenging activity (RSA), soluble sugar content, proline, glutathione, enzymatic antioxidants, and K+ content. Also, the results showed that naringenin pre-treatment can (partly) be overcome NaCl-induced stress on safflower seedlings, probably due to higher accumulation of plant biomass, total phenolic compound, RSA, catalase (CAT) activity, and K+/Na+ ratio as well as lowering the H2O2 and MDA content in the leaves. Conclusions Generally, it could be concluded that, pre-treatment of naringenin before stress could partly diminish NaCl-caused oxidative stress in safflower seedlings, probably due to improvement in enzymatic and non-enzymatic antioxidant and reduced cell membrane damage.

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Arbuscular Mycorrhiza and Plant Growth-promoting Bacteria Alleviate Drought Stress in Walnut

HortScience ◽

10.21273/hortsci13961-19 ◽

2019 ◽

Vol 54 (6) ◽

pp. 1087-1092 ◽

Cited By ~ 6

Author(s):

Azadeh Behrooz ◽

Kourosh Vahdati ◽

Farhad Rejali ◽

Mahmoud Lotfi ◽

Saadat Sarikhani ◽

...

Keyword(s):

Drought Stress ◽

Plant Growth ◽

Soluble Sugar ◽

Am Fungi ◽

Total Phenolic ◽

Plant Growth Promoting Bacteria ◽

Negative Effects ◽

Total Soluble Sugar ◽

Peroxidase Enzyme ◽

Plant Growth Promoting

Drought stress is one of the main constraints limiting worldwide crop production. Arbuscular mycorrhizae (AM) and plant growth-promoting bacteria (PGPB) such as Azotobacter chroococcum and Azospirillium lipofrum have been shown to alleviate drought stress effects. Therefore, the interaction effect of AM fungi [Glomus mosseae, G. etunicatum, and a mix of these (G. mix), and PGPB bacteria (Azotobacter chroococcum + Azospirillium lipofrum)] was investigated in 1-year-old walnut seedlings (cv. Chandler) under normal and drought stress conditions. Drought stress reduced growth (plant height, root length, number of leaves, and fresh weight) and leaf nutrient content (N, P, and Zn) significantly of walnut plants. In contrast, proline, total soluble sugar, starch peroxidase enzyme activity, and total phenolic content of walnut leaves increased under this stress. Application of fungi or bacteria, and especially their simultaneous use, alleviated the negative effects of drought stress on walnut seedlings. AM fungi and PGPB increased significantly the content of some metabolites, including total phenolic content, proline level, peroxidase activity, total soluble sugar, and starch content as well as peroxidase enzyme activity. This led to an increase in walnut plant growth under the drought stress condition. Among AM fungi, G. etunicatum was more effective in reducing drought stress symptoms than either G. mosseae or the G. mix of fungi. In conclusion, use of G. etunicatum, along with PGPB, can reduce negative effects of drought stress on walnut seedlings.

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Exogenous Melatonin Counteracts NaCl-Induced Damage by Regulating the Antioxidant System, Proline and Carbohydrates Metabolism in Tomato Seedlings

International Journal of Molecular Sciences ◽

10.3390/ijms20020353 ◽

2019 ◽

Vol 20 (2) ◽

pp. 353 ◽

Cited By ~ 26

Author(s):

Manzer Siddiqui ◽

Saud Alamri ◽

Mutahhar Al-Khaishany ◽

M. Khan ◽

Abdullah Al-Amri ◽

...

Keyword(s):

Plant Growth ◽

Antioxidant System ◽

Salt Content ◽

Soluble Carbohydrates ◽

Synthetase Activity ◽

Enzymatic Antioxidants ◽

Bisphosphate Carboxylase ◽

Exogenous Melatonin ◽

Chl A ◽

Tomato Seedlings

Melatonin, a natural agent, has multiple functions in animals as well as in plants. However, its possible roles in plants under abiotic stress are not clear. Nowadays, soil salinity is a major threat to global agriculture because a high soil salt content causes multiple stresses (hyperosmotic, ionic, and oxidative). Therefore, the aim of the present study was to explore: (1) the involvement of melatonin in biosynthesis of photosynthetic pigments and in regulation of photosynthetic enzymes, such as carbonic anhydrase (CA) and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco); (2) the role of melatonin in osmoregulation by proline and carbohydrate metabolism; and (3) the function of melatonin in the antioxidant defense system under salinity. Outcomes of the study reveal that under non-saline conditions, application of melatonin (20 and 50 µM) improved plant growth, viz. shoot length, root length, shoot fresh weight (FW), root FW, shoot dry weight (DW), root DW and leaf area and physio-biochemical parameters [chlorophyll (Chl) a and b, proline (Pro) and total soluble carbohydrates (TSC) content, and increased the activity of CA and Rubisco]. However, tomato seedlings treated with NaCl exhibited enhanced Chl degradation, electrolyte leakage (EL), malondialdehyde (MDA) and reactive oxygen species (ROS; superoxide and hydrogen peroxide). ROS were detected in leaf and root. Interestingly, application of melatonin improved plant growth and reduced EL, MDA and ROS levels through upregulation of photosynthesis enzymes (CA, Rubisco), antioxidant enzymes (superoxide dismutase, catalase, glutathione reductase and ascorbate reductase) and levels of non-enzymatic antioxidants [ascorbate (ASC) and reduced glutathione (GSH)], as well as by affecting the ASC—GSH cycle. Additionally, exogenous melatonin also improved osmoregulation by increasing the content of TSC, Pro and Δ1-pyrroline-5-carboxylate synthetase activity. These results suggest that melatonin has beneficial effects on tomato seedlings growth under both stress and non-stress conditions. Melatonin’s role in tolerance to salt stress may be associated with the regulation of enzymes involved in photosynthesis, the antioxidant system, metabolism of proline and carbohydrate, and the ASC—GSH cycle. Also, melatonin could be responsible for maintaining the high ratios of GSH/GSSG and ASC/DHA.

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Transcriptome Analysis Revealed GhWOX4 Intercedes Myriad Regulatory Pathways to Modulate Drought Tolerance and Vascular Growth in Cotton

International Journal of Molecular Sciences ◽

10.3390/ijms22020898 ◽

2021 ◽

Vol 22 (2) ◽

pp. 898

Author(s):

Muhammad Sajjad ◽

Xi Wei ◽

Lisen Liu ◽

Fuguang Li ◽

Xiaoyang Ge

Keyword(s):

Transcription Factors ◽

Drought Stress ◽

Drought Tolerance ◽

Plant Growth ◽

Growth And Development ◽

Differentially Expressed ◽

Growth And Yield ◽

Regulatory Pathways ◽

Vascular Growth

Cotton is a paramount cash crop around the globe. Among all abiotic stresses, drought is a leading cause of cotton growth and yield loss. However, the molecular link between drought stress and vascular growth and development is relatively uncharted. Here, we validated a crucial role of GhWOX4, a transcription factor, modulating drought stress with that of vasculature growth in cotton. Knock-down of GhWOX4 decreased the stem width and severely compromised vascular growth and drought tolerance. Conversely, ectopic expression of GhWOX4 in Arabidopsis enhanced the tolerance to drought stress. Comparative RNAseq analysis revealed auxin responsive protein (AUX/IAA), abscisic acid (ABA), and ethylene were significantly induced. Additionally, MYC-bHLH, WRKY, MYB, homeodomain, and heat-shock transcription factors (HSF) were differentially expressed in control plants as compared to GhWOX4-silenced plants. The promotor zone of GhWOX4 was found congested with plant growth, light, and stress response related cis-elements. differentially expressed genes (DEGs) related to stress, water deprivation, and desiccation response were repressed in drought treated GhWOX4-virus-induced gene silencing (VIGS) plants as compared to control. Gene ontology (GO) functions related to cell proliferation, light response, fluid transport, and flavonoid biosynthesis were over-induced in TRV: 156-0 h/TRV: 156-1 h (control) in comparison to TRV: VIGS-0 h/TRV: VIGS-1 h (GhWOX4-silenced) plants. This study improves our context for elucidating the pivotal role of GhWOX4 transcription factors (TF), which mediates drought tolerance, plays a decisive role in plant growth and development, and is likely involved in different regulatory pathways in cotton.

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