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17 pages, 4794 KiB

Open AccessArticle

Components of the Phenylpropanoid Pathway in the Implementation of the Protective Effect of Sodium Nitroprusside on Wheat under Salinity

by Dilara Maslennikova, Sergey Ivanov, Svetlana Petrova, Guzel Burkhanova, Igor Maksimov and Oksana Lastochkina

Plants 2023, 12(11), 2123; https://doi.org/10.3390/plants12112123 - 26 May 2023

Cited by 2 | Viewed by 902

Abstract

Nitric oxide (NO) is a multifunctional, gaseous signaling molecule implicated in both physiological and protective responses to biotic and abiotic stresses, including salinity. In this work, we studied the effects of 200 µM exogenous sodium nitroprusside (SNP, a donor of NO) on the [...] Read more.

Nitric oxide (NO) is a multifunctional, gaseous signaling molecule implicated in both physiological and protective responses to biotic and abiotic stresses, including salinity. In this work, we studied the effects of 200 µM exogenous sodium nitroprusside (SNP, a donor of NO) on the components of the phenylpropanoid pathway, such as lignin and salicylic acid (SA), and its relationship with wheat seedling growth under normal and salinity (2% NaCl) conditions. It was established that exogenous SNP contributed to the accumulation of endogenous SA and increased the level of transcription of the pathogenesis-related protein 1 (PR1) gene. It was found that endogenous SA played an important role in the growth-stimulating effect of SNP, as evidenced by the growth parameters. In addition, under the influence of SNP, the activation of phenylalanine ammonia lyase (PAL), tyrosine ammonia lyase (TAL), and peroxidase (POD), an increase in the level of transcription of the TaPAL and TaPRX genes, and the acceleration of lignin accumulation in the cell walls of roots were revealed. Such an increase in the barrier properties of the cell walls during the period of preadaptation played an important role in protection against salinity stress. Salinity led to significant SA accumulation and lignin deposition in the roots, strong activation of TAL, PAL, and POD, and suppression of seedling growth. Pretreatment with SNP under salinity conditions resulted in additional lignification of the root cell walls, decreased stress-induced endogenous SA generation, and lower PAL, TAL, and POD activities in comparison to untreated stressed plants. Thus, the obtained data suggested that during pretreatment with SNP, phenylpropanoid metabolism was activated (i.e., lignin and SA), which contributed to reducing the negative effects of salinity stress, as evidenced by the improved plant growth parameters. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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22 pages, 6940 KiB

Open AccessArticle

Effect of Seed Priming with Endophytic Bacillus subtilis on Some Physio-Biochemical Parameters of Two Wheat Varieties Exposed to Drought after Selective Herbicide Application

by Oksana Lastochkina, Albina Yakupova, Irina Avtushenko, Artem Lastochkin and Ruslan Yuldashev

Plants 2023, 12(8), 1724; https://doi.org/10.3390/plants12081724 - 20 Apr 2023

Cited by 8 | Viewed by 1540

Abstract

Wheat plants are frequently exposed to combined herbicide and drought stress (HDS) which induces complex responses negatively, affects productivity, and is becoming more exacerbated with current climate change. In this work, we studied the influence of seed priming with endophytic bacteria Bacillus subtilis [...] Read more.

Wheat plants are frequently exposed to combined herbicide and drought stress (HDS) which induces complex responses negatively, affects productivity, and is becoming more exacerbated with current climate change. In this work, we studied the influence of seed priming with endophytic bacteria Bacillus subtilis (strains 104 and 26D) on growth and tolerance of two wheat (Triticum aestivum L.) varieties (E70—drought tolerant; SY—drought susceptible) exposed to soil drought after application of selective herbicide Sekator^® Turbo in pot experiments under controlled conditions; 17-day-old plants sprayed with herbicide and after 3 days were subjected to soil drought by stopping irrigating the plants for 7 days with subsequent resumption of normal irrigation (recovery). Additionally, the growth of tested strains (104, 26D) in the presence of different concentrations of herbicide Sekator^® Turbo and drought (PEG-6000) were evaluated. It was established that both strains are herbicide and drought tolerant and capable to improve seed germination and early seedlings’ growth under different herbicide and drought stress degrees. The results of pot experiments showed that HDS exposure declined growth (plant length, biomass), photosynthetic pigments (chlorophyll a and b), leaf area, and increased lipid peroxidation (LPO) and proline accumulation in plants, demonstrating higher damaging effects for SY variety. Strains 104 and 26D mitigated (in different levels) such negative impacts of HDS on growth of both varieties by increasing length of roots and shoots, biomass, photosynthetic pigments (chlorophyll a and b), and leaf area, reducing stress-caused LPO (i.e., malondialdehyde), and regulating proline biosynthesis, as well as contributing to a faster recovery of growth, photosynthetic pigments, and redox-status of plants in post-stress period in comparison with non-primed plants. These ultimately manifested in forming a better grain yield of both varieties primed with 104, 26D, and exposed to HDS. Thus, both strains 104 and 26D (which are herbicide and drought tolerant) may be used as seed priming agents to improve wheat HDS tolerance and grain yield; however, strain 104 more effectively protected plants of E70, while strain 26D—plants of SY. Further research should be focused on understanding the mechanisms that determine the strain and variety-specificity of endophytic symbiosis and the role of bacteria in the modulation of physiological states of primed plants under stress conditions, including HDS. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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22 pages, 2204 KiB

Open AccessArticle

Appropriate Application Methods for Salicylic Acid and Plant Nutrients Combinations to Promote Morpho-Physiological Traits, Production, and Water Use Efficiency of Wheat under Normal and Deficit Irrigation in an Arid Climate

by Majed Alotaibi, Salah El-Hendawy, Nabil Mohammed, Bazel Alsamin and Yahya Refay

Plants 2023, 12(6), 1368; https://doi.org/10.3390/plants12061368 - 19 Mar 2023

Cited by 3 | Viewed by 1752

Abstract

Freshwater shortage and inadequate nutrient management are the two major challenges for sustainable wheat production in arid agro-ecosystems. Relatively little is known about the positive roles of the application methods for the combination of salicylic acid (SA) and plant nutrients in sustaining wheat [...] Read more.

Freshwater shortage and inadequate nutrient management are the two major challenges for sustainable wheat production in arid agro-ecosystems. Relatively little is known about the positive roles of the application methods for the combination of salicylic acid (SA) and plant nutrients in sustaining wheat production under arid climatic conditions. A two-year field study was undertaken to assess the impact of seven treatments for the integrated application of SA, macronutrients, and micronutrients on the morpho-physiological traits, yield, and irrigation water use efficiency (IWUE) of wheat subjected to full (FL) and limited (LM) irrigation regimes. The results showed that the LM regime caused a significant reduction in different plant growth traits, relative water content, chlorophyll pigments, yield components, and yield, while a significant increase was observed in IWUE. The sole application of SA or co-application with micronutrients through soil did not significantly affect the studied traits under the FL regime, while they achieved some improvement over untreated plants under the LM regime. Based on the different multivariate analyses, the soil and foliar applications for the combinations of SA and micronutrients, as well as a foliar application for the combinations of SA, macronutrients, and micronutrients were identified as an efficient option for mitigating the negative impacts of water deficit stress and enhancing the growth and production of wheat under normal conditions. In conclusion, the results obtained herein indicated that the co-application of SA and macro- and micronutrients is an effective option to greatly enhance and improve the growth and production of wheat crops in water-scarce countries of arid regions, such as Saudi Arabia, while an appropriate application method for this combination was required for positive effects. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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24 pages, 2367 KiB

Open AccessArticle

Integrating Application Methods and Concentrations of Salicylic Acid as an Avenue to Enhance Growth, Production, and Water Use Efficiency of Wheat under Full and Deficit Irrigation in Arid Countries

by Nabil Mohammed, Salah El-Hendawy, Bazel Alsamin, Muhammad Mubushar and Yaser Hassan Dewir

Plants 2023, 12(5), 1019; https://doi.org/10.3390/plants12051019 - 23 Feb 2023

Cited by 3 | Viewed by 1821

Abstract

As water deficit in arid countries has already become the norm rather than the exception, water conservation in crop production processes has become very critical. Therefore, it is urgent to develop feasible strategies to achieve this goal. Exogenous application of salicylic acid (SA) [...] Read more.

As water deficit in arid countries has already become the norm rather than the exception, water conservation in crop production processes has become very critical. Therefore, it is urgent to develop feasible strategies to achieve this goal. Exogenous application of salicylic acid (SA) has been proposed as one of the effective and economical strategies for mitigating water deficit in plants. However, the recommendations concerning the proper application methods (AMs) and the optimal concentrations (Cons) of SA under field conditions seem contradictory. Here, a two-year field study was conducted to compare the effects of twelve combinations of AMs and Cons on the vegetative growth, physiological parameters, yield, and irrigation water use efficiency (IWUE) of wheat under full (FL) and limited (LM) irrigation regimes. These combinations included seed soaking in purified water (S₀), 0.5 mM SA (S₁), and 1.0 mM SA (S₂); foliar spray of SA at concentrations of 1.0 mM (F₁), 2.0 mM (F₂), and 3.0 mM (F₃); and combinations of S₁ and S₂ with F₁ (S₁F₁ and S₂F₁), F₂ (S₁F₂ and S₂F₂), and F₃ (S₁F₃ and S₂F₃). The results showed that the LM regime caused a significant reduction in all vegetative growth, physiological, and yield parameters, while it led to an increase in IWUE. The application of SA through seed soaking, foliar application, and a combination of both methods increased all of the studied parameters in all the evaluated times, resulting in higher values for all parameters than the treatment without SA (S₀). The multivariate analyses, including principal component analysis and heatmapping, identified the foliar application method with 1–3 mM SA alone or in combination with seed soaking with 0.5 mM SA as the best treatments for the optimal performance of wheat under both irrigation regimes. Overall, our results indicated that exogenous application of SA has the potential to greatly improve growth, yield, and IWUE under limited water application, while optimal coupling combinations of AMs and Cons were required for positive effects in field conditions. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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13 pages, 8440 KiB

Open AccessArticle

The Effect of an Extremely Low-Frequency Electromagnetic Field on the Drought Sensitivity of Wheat Plants

by N. S. Mshenskaya, M. A. Grinberg, E. A. Kalyasova, V. A. Vodeneev, N. V. Ilin, N. N. Slyunyaev, E. A. Mareev and Y. V. Sinitsyna

Plants 2023, 12(4), 826; https://doi.org/10.3390/plants12040826 - 13 Feb 2023

Cited by 4 | Viewed by 2550

Abstract

Extremely low-frequency magnetic fields are thought to be capable of modulating the resistance of plants to adverse factors, particularly drought. Magnetic fields in this frequency range occur in nature in connection with so-called Schumann resonances, excited by lightning discharges in the Earth–ionosphere cavity. [...] Read more.

Extremely low-frequency magnetic fields are thought to be capable of modulating the resistance of plants to adverse factors, particularly drought. Magnetic fields in this frequency range occur in nature in connection with so-called Schumann resonances, excited by lightning discharges in the Earth–ionosphere cavity. The aim of this work was to identify the influence of a magnetic field with a frequency of 14.3 Hz (which corresponds to the second Schumann harmonic) on the transpiration and photosynthesis of wheat plants under the influence of drought. The activity of photosynthesis processes, the crop water stress index, relative water content and leaf area were determined during drought intensification. At the end of the experiment, on the 12th day of drought, the length, and fresh and dry weight of wheat shoots were measured. The results obtained indicate a protective effect of the magnetic field on plants in unfavorable drought conditions; the magnetic field delayed the development of harmful changes in the transpiration and photosynthesis processes for several days. At the same time, in the absence of the stressor (drought), the effect of the electromagnetic field was not detected, except for a decrease in relative transpiration. In favorable conditions, there were only minimal modifications of the photosynthetic processes and transpiration by the magnetic field. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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29 pages, 6823 KiB

Open AccessArticle

The Response of Chromosomally Engineered Durum Wheat-Thinopyrum ponticum Recombinant Lines to the Application of Heat and Water-Deficit Stresses: Effects on Physiological, Biochemical and Yield-Related Traits

by Gloria Giovenali, Ljiljana Kuzmanović, Alessandra Capoccioni and Carla Ceoloni

Plants 2023, 12(4), 704; https://doi.org/10.3390/plants12040704 - 05 Feb 2023

Cited by 1 | Viewed by 1141

Abstract

Abiotic stress occurrence and magnitude are alarmingly intensifying worldwide. In the Mediterranean basin, heat waves and precipitation scarcity heavily affect major crops such as durum wheat (DW). In the search for tolerant genotypes, the identification of genes/QTL in wild wheat relatives, naturally adapted [...] Read more.

Abiotic stress occurrence and magnitude are alarmingly intensifying worldwide. In the Mediterranean basin, heat waves and precipitation scarcity heavily affect major crops such as durum wheat (DW). In the search for tolerant genotypes, the identification of genes/QTL in wild wheat relatives, naturally adapted to harsh environments, represents a useful strategy. We tested three DW-Thinopyrum ponticum recombinant lines (R5+, R112+, R23+), their control sibs lacking any alien introgression, and the heat-tolerant cv. Margherita for their physiological, biochemical and yield response to heat stress (HS) application at anthesis, also in combination with water-deficit stress applied from booting until maturity. Under HS, R5+ and R112+ (23%- and 28%-long 7el₁L Th. ponticum chromosome segment distally inserted on DW 7AL, respectively) showed remarkable stability of the yield-related traits; in turn, R23+ (40%-long 7el₁L segment), despite a decreased grain yield, exhibited a greater spike fertility index and proline content in spike than its control sib. Under water-deficit + HS, R5+ showed the highest increment in water use efficiency and in flag leaf proline content, accompanied by the lowest yield penalty even vs. Margherita. This research confirms the value of harnessing wild gene pools to enhance DW stress tolerance and represents a starting point for elucidating the mechanisms of Thinopyrum spp. contribution to this relevant breeding target. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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18 pages, 1654 KiB

Open AccessArticle

The Chlorophyll Fluorescence Parameter F_v/F_m Correlates with Loss of Grain Yield after Severe Drought in Three Wheat Genotypes Grown at Two CO₂ Concentrations

by Søren Gjedde Sommer, Eusun Han, Xiangnan Li, Eva Rosenqvist and Fulai Liu

Plants 2023, 12(3), 436; https://doi.org/10.3390/plants12030436 - 18 Jan 2023

Cited by 12 | Viewed by 2584

Abstract

Three genotypes of wheat grown at two CO₂ concentrations were used in a drought experiment, where water was withheld from the pots at anthesis until stomatal conductance (g_s) dropped below 10% of the control and photosynthesis (A) approached zero. The [...] Read more.

Three genotypes of wheat grown at two CO₂ concentrations were used in a drought experiment, where water was withheld from the pots at anthesis until stomatal conductance (g_s) dropped below 10% of the control and photosynthesis (A) approached zero. The genotypes had different leaf area (Gladius < LM19 < LM62) and while photosynthesis and shoot growth were boosted by elevated CO₂, the water use and drying rate were more determined by canopy size than by stomatal density and conductance. The genotypes responded differently regarding number of fertile tillers, seeds per spike and 1000 kernel weight and, surprisingly, the largest genotype (LM62) with high water use showed the lowest relative decrease in grain yield. The maximum photochemical efficiency of photosystem II (F_v/F_m) was only affected on the last day of the drought when the stomata were almost closed although some variation in A was still seen between the genotypes. A close correlation was found between F_v/F_m and % loss of grain yield. It indicates that the precise final physiological stress level measured by F_v/F_m at anthesis/early kernel filling could effectively predict percentage final yield loss, and LM62 was slightly less stressed than the other genotypes, due to only a small discrepancy in finalising the drying period. Therefore, F_v/F_m can be used as a proxy for estimating the yield performance of wheat after severe drought at anthesis. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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21 pages, 4615 KiB

Open AccessArticle

Morpho-Physiological and Hormonal Response of Winter Wheat Varieties to Drought Stress at Stem Elongation and Anthesis Stages

by Jurica Duvnjak, Ante Lončarić, Lidija Brkljačić, Dunja Šamec, Hrvoje Šarčević, Branka Salopek-Sondi and Valentina Španić

Plants 2023, 12(3), 418; https://doi.org/10.3390/plants12030418 - 17 Jan 2023

Cited by 6 | Viewed by 2412

Abstract

Drought stress can significantly reduce wheat growth and development as well as grain yield. This study investigated morpho-physiological and hormonal (abscisic (ABA) and salicylic (SA) acids) responses of six winter wheat varieties during stem elongation and anthesis stage as well grain yield-related traits [...] Read more.

Drought stress can significantly reduce wheat growth and development as well as grain yield. This study investigated morpho-physiological and hormonal (abscisic (ABA) and salicylic (SA) acids) responses of six winter wheat varieties during stem elongation and anthesis stage as well grain yield-related traits were measured after harvest. To examine drought response, plants were exposed to moderate non-lethal drought stress by withholding watering for 45 and 65% of the volumetric soil moisture content (VSMC) for 14 days at separate experiments for each of those two growth stages. During the stem elongation phase, ABA was increased, confirming the stress status of plants, and SA showed a tendency to increase, suggesting their role as stress hormones in the regulation of stress response, such as the increase in the number of leaves and tillers in drought stress conditions, and further keeping turgor pressure and osmotic adjustment in leaves. At the anthesis stage, heavier drought stress resulted in ABA accumulation in flag leaves that generated an integrated response of maturation, where ABA was not positively correlated with any of investigated traits. After harvest, the variety Bubnjar, followed by Pepeljuga and Anđelka, did not significantly decrease the number of grains per ear and 1000 kernel weight (except Anđelka) in drought treatments, thus, declaring them more tolerant to drought. On the other hand, Rujana, Fifi, and particularly Silvija experienced the highest reduction in grain yield-related traits, considering them drought-sensitive varieties. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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19 pages, 2148 KiB

Open AccessArticle

Phenotypic and Genotypic Diversity of Roots Response to Salt in Durum Wheat Seedlings

by Ieva Urbanavičiūtė, Luca Bonfiglioli and Mario A. Pagnotta

Plants 2023, 12(2), 412; https://doi.org/10.3390/plants12020412 - 16 Jan 2023

Cited by 4 | Viewed by 1892

Abstract

Soil salinity is a serious threat to food production now and in the near future. In this study, the root system of six durum wheat genotypes, including one highly salt-tolerant (J. Khetifa) used as a check genotype, was evaluated, by a high-throughput phenotyping [...] Read more.

Soil salinity is a serious threat to food production now and in the near future. In this study, the root system of six durum wheat genotypes, including one highly salt-tolerant (J. Khetifa) used as a check genotype, was evaluated, by a high-throughput phenotyping system, under control and salt conditions at the seedling stage. Genotyping was performed using 11 SSR markers closely linked with genome regions associated with root traits. Based on phenotypic cluster analysis, genotypes were grouped differently under control and salt conditions. Under control conditions, genotypes were clustered mainly due to a root angle, while under salt stress, genotypes were grouped according to their capacity to maintain higher roots length, volume, and surface area, as J. Khetifa, Sebatel, and Azeghar. SSR analysis identified a total of 42 alleles, with an average of about three alleles per marker. Moreover, quite a high number of Private alleles in total, 18 were obtained. The UPGMA phenogram of the Nei (1972) genetic distance clusters for 11 SSR markers and all phenotypic data under control conditions discriminate genotypes almost into the same groups. The study revealed as the combination of high-throughput systems for phenotyping with SSR markers for genotyping it’s a useful tool to provide important data for the selection of suitable parental lines for salt-tolerance breeding. Nevertheless, the narrow root angle, which is an important trait in drought tolerance, is not a good indicator of salt tolerance. Instated for salt tolerance is more important the amount of roots. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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20 pages, 6369 KiB

Open AccessArticle

Spermine-Salicylic Acid Interplay Restrains Salt Toxicity in Wheat (Triticum aestivum L.)

by Neveen B. Talaat and Alaa M. A. Hanafy

Plants 2023, 12(2), 352; https://doi.org/10.3390/plants12020352 - 12 Jan 2023

Cited by 6 | Viewed by 1566

Abstract

Spermine (SPM) and salicylic acid (SA) are plant growth regulators, eliciting specific responses against salt toxicity. In this study, the potential role of 30 mgL⁻¹ SPM and/or 100 mgL⁻¹ SA in preventing salt damage was investigated. Wheat plants were grown under [...] Read more.

Spermine (SPM) and salicylic acid (SA) are plant growth regulators, eliciting specific responses against salt toxicity. In this study, the potential role of 30 mgL⁻¹ SPM and/or 100 mgL⁻¹ SA in preventing salt damage was investigated. Wheat plants were grown under non-saline or saline conditions (6.0 and 12.0 dS m⁻¹) with and without SA and/or SPM foliar applications. Exogenously applied SA and/or SPM alleviated the inhibition of plant growth and productivity under saline conditions by increasing Calvin cycle enzyme activity. Foliage applications also improved ascorbate peroxidase, monodehydroascorbate reductase, dehydroascorbate reductase, and glutathione reductase activities, which effectively scavenged hydrogen peroxide and superoxide radicals in stressed plants. Furthermore, foliar treatments increased antioxidants such as ascorbate and glutathione, which effectively detoxified reactive oxygen species (ROS). Exogenous applications also increased N, P, and K⁺ acquisition, roots’ ATP content, and H⁺-pump activity, accompanied by significantly lower Na⁺ accumulation in stressed plants. Under saline environments, exogenous SA and/or SPM applications raised endogenous SA and SPM levels. Co-application of SA and SPM gave the best response. The newly discovered data suggest that the increased activities of Calvin cycle enzymes, root H⁺-pump, and antioxidant defense machinery in treated plants are a mechanism for salt tolerance. Therefore, combining the use of SA and SPM can be a superior method for reducing salt toxicity in sustainable agricultural systems. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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19 pages, 2429 KiB

Open AccessArticle

Role of Endogenous Salicylic Acid as a Hormonal Intermediate in the Bacterial Endophyte Bacillus subtilis-Induced Protection of Wheat Genotypes Contrasting in Drought Susceptibility under Dehydration

by Oksana Lastochkina, Sergey Ivanov, Svetlana Petrova, Darya Garshina, Alsu Lubyanova, Ruslan Yuldashev, Bulat Kuluev, Evgenia Zaikina, Dilara Maslennikova, Chulpan Allagulova, Irina Avtushenko, Albina Yakupova and Rashit Farkhutdinov

Plants 2022, 11(23), 3365; https://doi.org/10.3390/plants11233365 - 03 Dec 2022

Cited by 5 | Viewed by 1766

Abstract

Endophytic Bacillus subtilis is a non-pathogenic beneficial bacterium which promotes plant growth and tolerance to abiotic stresses, including drought. However, the underlying physiological mechanisms are not well understood. In this study, the potential role that endogenous salicylic acid (SA) plays in regulating endophytic [...] Read more.

Endophytic Bacillus subtilis is a non-pathogenic beneficial bacterium which promotes plant growth and tolerance to abiotic stresses, including drought. However, the underlying physiological mechanisms are not well understood. In this study, the potential role that endogenous salicylic acid (SA) plays in regulating endophytic B. subtilis-mediated drought tolerance in wheat (Triticum aestivum L.) was examined. The study was conducted on genotypes with contrasting levels of intrinsic drought tolerance (drought-tolerant (DT) cv. Ekada70; drought-susceptible (DS) cv. Salavat Yulaev). It was revealed that B. subtilis 10-4 promoted endogenous SA accumulation and increased the relative level of transcripts of the PR-1 gene, a marker of the SA-dependent defense pathway, but two wheat cultivars responded differently, with the highest levels exhibited in DT wheat seedlings. These had a positive correlation with the ability of strain 10-4 to effectively protect DT wheat seedlings against drought injury by decreasing osmotic and oxidative damages (i.e., proline, water holding capacity (WHC), and malondialdehyde (MDA)). However, the use of the SA biosynthesis inhibitor 1-aminobenzotriazole prevented endogenous SA accumulation under normal conditions and the maintenance of its increased level under stress as well as abolished the effects of B. subtilis treatment. Particularly, the suppression of strain 10-4-induced effects on proline and WHC, which are both contributing factors to dehydration tolerance, was found. Moreover, the prevention of strain 10-4-induced wheat tolerance to the adverse impacts of drought, as judged by the degree of membrane lipid peroxidation (MDA) and plant growth (length, biomass), was revealed. Thus, these data provide an argument in favor of a key role of endogenous SA as a hormone intermediate in triggering the defense responses by B. subtilis 10-4, which also afford the foundation for the development of the bacterial-induced tolerance of these two different wheat genotypes under dehydration. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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24 pages, 7776 KiB

Open AccessArticle

Transcriptome and Proteome Co-Profiling Offers an Understanding of Pre-Harvest Sprouting (PHS) Molecular Mechanisms in Wheat (Triticum aestivum)

by Sang Yong Park, Woo Joo Jung, Geul Bang, Heeyoun Hwang and Jae Yoon Kim

Plants 2022, 11(21), 2807; https://doi.org/10.3390/plants11212807 - 22 Oct 2022

Cited by 3 | Viewed by 1800

Abstract

While wheat (Triticum aestivum L.) is a widely grown and enjoyed crop, the diverse and complex global situation and climate are exacerbating the instability of its supply. In particular, pre-harvest sprouting (PHS) is one of the major abiotic stresses that frequently occurs [...] Read more.

While wheat (Triticum aestivum L.) is a widely grown and enjoyed crop, the diverse and complex global situation and climate are exacerbating the instability of its supply. In particular, pre-harvest sprouting (PHS) is one of the major abiotic stresses that frequently occurs due to irregular climate conditions, causing serious damage to wheat and its quality. In this study, transcriptomic analysis with RNA-seq and proteomic analysis with LC-MS/MS were performed in PHS-treated spikes from two wheat cultivars presenting PHS sensitivity and tolerance, respectively. A total of 13,154 differentially expressed genes (DEGs) and 706 differentially expressed proteins (DEPs) were identified in four comparison groups between the susceptible/tolerant cultivars. Gene function and correlation analysis were performed to determine the co-profiled genes and proteins affected by PHS treatment. In the functional annotation of each comparative group, similar functions were confirmed in each cultivar under PHS treatment; however, in Keumgang PHS+7 (K7) vs. Woori PHS+7 (W7), functional annotations presented clear differences in the ”spliceosome” and ”proteasome” pathways. In addition, our results indicate that alternative splicing and ubiquitin–proteasome support the regulation of germination and seed dormancy. This study provides an advanced understanding of the functions involved in transcription and translation related to PHS mechanisms, thus enabling specific proposals for the further analysis of germination and seed dormancy mechanisms and pathways in wheat. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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25 pages, 18722 KiB

Open AccessArticle

Genome-Wide Identification and Expression Analysis of the Zinc Finger Protein Gene Subfamilies under Drought Stress in Triticum aestivum

by Zhaoming Wu, Shenghai Shen, Yueduo Wang, Weiqi Tao, Ziqi Zhao, Xiangli Hu and Pei Yu

Plants 2022, 11(19), 2511; https://doi.org/10.3390/plants11192511 - 26 Sep 2022

Cited by 5 | Viewed by 2070

Abstract

The zinc finger protein (ZFP) family is one of plants’ most diverse family of transcription factors. These proteins with finger-like structural domains have been shown to play a critical role in plant responses to abiotic stresses such as drought. This study aimed to [...] Read more.

The zinc finger protein (ZFP) family is one of plants’ most diverse family of transcription factors. These proteins with finger-like structural domains have been shown to play a critical role in plant responses to abiotic stresses such as drought. This study aimed to systematically characterize Triticum aestivum ZFPs (TaZFPs) and understand their roles under drought stress. A total of 9 TaC2H2, 38 TaC3HC4, 79 TaCCCH, and 143 TaPHD were identified, which were divided into 4, 7, 12, and 14 distinct subgroups based on their phylogenetic relationships, respectively. Segmental duplication dominated the evolution of four subfamilies and made important contributions to the large-scale amplification of gene families. Syntenic relationships, gene duplications, and Ka/Ks result consistently indicate a potential strong purifying selection on TaZFPs. Additionally, TaZFPs have various abiotic stress-associated cis-acting regulatory elements and have tissue-specific expression patterns showing different responses to drought and heat stress. Therefore, these genes may play multiple functions in plant growth and stress resistance responses. This is the first comprehensive genome-wide analysis of ZFP gene families in T. aestivum to elucidate the basis of their function and resistance mechanisms, providing a reference for precise manipulation of genetic engineering for drought resistance in T. aestivum. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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18 pages, 4733 KiB

Open AccessArticle

Impacts of Drought Stress and Mycorrhizal Inoculation on the Performance of Two Spring Wheat Cultivars

by Caroline Pons and Caroline Müller

Plants 2022, 11(17), 2187; https://doi.org/10.3390/plants11172187 - 24 Aug 2022

Cited by 4 | Viewed by 1974

Abstract

Cereal production is becoming challenging, given ongoing climate change. Arbuscular mycorrhizal fungi (AMF) are discussed to mitigate effects of drought for plants and enhance nutrient uptake. Thus, we investigated the impacts of drought and mycorrhiza on the growth and allocation patterns of two [...] Read more.

Cereal production is becoming challenging, given ongoing climate change. Arbuscular mycorrhizal fungi (AMF) are discussed to mitigate effects of drought for plants and enhance nutrient uptake. Thus, we investigated the impacts of drought and mycorrhiza on the growth and allocation patterns of two cultivars of spring wheat (Triticum aestivum). Plants were grown under three irrigation regimes (well-watered, continuous or pulsed drought) and in three substrates (absence or presence of one or three AMF species). Applied water use efficiency (WUE_applied), harvest index (HI) and contents of carbon (C), nitrogen (N) and phosphorous (P) were determined when grains were watery ripe. When grains were hard, again, WUE_applied, HI and the thousand-kernel weight were measured. The WUE_applied and HI were lowest in plants under pulsed drought stress at the second harvest, while the thousand-kernel weight was lower in mycorrhized compared to non-mycorrhized plants. The C/N ratio dropped with increasing drought stress but was enhanced by mycorrhiza, while the P content was surprisingly unaffected by mycorrhiza. The total root length colonization was higher in substrates with the AMF mix, but overall, fungal presence could not alleviate the effects of drought. Our results highlight the complexity of responses to challenging environments in this highly domesticated species. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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22 pages, 1199 KiB

Open AccessArticle

Transpirational Leaf Cooling Effect Did Not Contribute Equally to Biomass Retention in Wheat Genotypes under High Temperature

by Helen Bramley, S. R. W. M. Chandima J. K. Ranawana, Jairo A. Palta, Katia Stefanova and Kadambot H. M. Siddique

Plants 2022, 11(16), 2174; https://doi.org/10.3390/plants11162174 - 21 Aug 2022

Cited by 3 | Viewed by 1753

Abstract

High temperature and water deficit are the most critical yield-limiting environmental factors for wheat in rainfed environments. It is important to understand the heat avoidance mechanisms and their associations with leaf morpho-physiological traits that allow crops to stay cool and retain high biomass [...] Read more.

High temperature and water deficit are the most critical yield-limiting environmental factors for wheat in rainfed environments. It is important to understand the heat avoidance mechanisms and their associations with leaf morpho-physiological traits that allow crops to stay cool and retain high biomass under warm and dry conditions. We examined 20 morpho-physiologically diverse wheat genotypes under ambient and elevated temperatures (T_air) to investigate whether increased water use leads to high biomass retention due to increased leaf cooling. An experiment was conducted under well-watered conditions in two partially controlled glasshouses. We measured plant transpiration (T_r), leaf temperature (T_leaf), vapor pressure deficit (VPD), and associated leaf morpho-physiological characteristics. High water use and leaf cooling increased biomass retention under high temperatures, but increased use did not always increase biomass retention. Some genotypes maintained biomass, irrespective of water use, possibly through mechanisms other than leaf cooling, indicating their adaptation under water shortage. Genotypic differences in leaf cooling capacity did not always correlate with T_r (VPD) response. In summary, the contribution of high water use or the leaf cooling effect on biomass retention under high temperature is genotype-dependent and possibly due to variations in leaf morpho-physiological traits. These findings are useful for breeding programs to develop climate resilient wheat cultivars. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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15 pages, 854 KiB

Open AccessArticle

Oxidative Stress Mitigation by Chitosan Nanoparticles in Durum Wheat Also Affects Phytochemicals and Technological Quality of Bran and Semolina

by Valentina Picchi, Antonella Calzone, Serena Gobbi, Sara Paccani, Roberto Lo Scalzo, Alessandra Marti and Franco Faoro

Plants 2022, 11(15), 2021; https://doi.org/10.3390/plants11152021 - 03 Aug 2022

Cited by 1 | Viewed by 1354

Abstract

In our previous work, durum wheat cv. Fabulis was grown over two consecutive seasons (2016–2017 and 2017–2018) in an experimental field in the north of Italy. With the aim of mitigating oxidative stress, plants were subjected to four treatments (deionized water, CHT 0.05 [...] Read more.

In our previous work, durum wheat cv. Fabulis was grown over two consecutive seasons (2016–2017 and 2017–2018) in an experimental field in the north of Italy. With the aim of mitigating oxidative stress, plants were subjected to four treatments (deionized water, CHT 0.05 mg/mL, CHT-NPs, and CHT-NPs-NAC) three times during the experiment. Chitosan nanoparticles (CHT-NPs) reduced symptom severity on wheat leaves and positively influenced the final grain yield. The present work aimed at investigating whether CHT treatments and particularly N-acetyl cysteine (NAC)-loaded or -unloaded CHT-NPs, while triggering plant defense mechanisms, might also vary the nutritional and technological quality of grains. For this purpose, the grains harvested from the previous experiment were analyzed for their content in phytochemicals and for their technological properties. The results showed that CHT increased the polyphenol and tocopherol content and the reducing capacity of bran and semolina, even if the positive effect of the nano-formulation remained still unclear and slightly varied between the two years of cultivation. The positive effect against oxidative stress induced by the chitosan treatments was more evident in the preservation of both the starch pasting properties and gluten aggregation capacity, indicating that the overall technological quality of semolina was maintained. Our data confirm the role of chitosan as an elicitor of the antioxidant defense system in wheat also at the grain level. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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26 pages, 2064 KiB

Open AccessArticle

Genetic Potential and Inheritance Patterns of Physiological, Agronomic and Quality Traits in Bread Wheat under Normal and Water Deficit Conditions

by Mohamed M. Kamara, Medhat Rehan, Amany M. Mohamed, Rania F. El Mantawy, Ahmed M. S. Kheir, Diaa Abd El-Moneim, Fatmah Ahmed Safhi, Salha M. ALshamrani, Emad M. Hafez, Said I. Behiry, Mohamed M. A. Ali and Elsayed Mansour

Plants 2022, 11(7), 952; https://doi.org/10.3390/plants11070952 - 31 Mar 2022

Cited by 21 | Viewed by 2771

Abstract

Water scarcity is a major environmental stress that adversatively impacts wheat growth, production, and quality. Furthermore, drought is predicted to be more frequent and severe as a result of climate change, particularly in arid regions. Hence, breeding for drought-tolerant and high-yielding wheat genotypes [...] Read more.

Water scarcity is a major environmental stress that adversatively impacts wheat growth, production, and quality. Furthermore, drought is predicted to be more frequent and severe as a result of climate change, particularly in arid regions. Hence, breeding for drought-tolerant and high-yielding wheat genotypes has become more decisive to sustain its production and ensure global food security with continuing population growth. The present study aimed at evaluating different parental bread wheat genotypes (exotic and local) and their hybrids under normal and drought stress conditions. Gene action controlling physiological, agronomic, and quality traits through half-diallel analysis was applied. The results showed that water-deficit stress substantially decreased chlorophyll content, photosynthetic efficiency (FV/Fm), relative water content, grain yield, and yield attributes. On the other hand, proline content, antioxidant enzyme activities (CAT, POD, and SOD), grain protein content, wet gluten content, and dry gluten content were significantly increased compared to well-watered conditions. The 36 evaluated genotypes were classified based on drought tolerance indices into 5 groups varying from highly drought-tolerant (group A) to highly drought-sensitive genotypes (group E). The parental genotypes P₃ and P₈ were identified as good combiners to increase chlorophyll b, total chlorophyll content, relative water content, grain yield, and yield components under water deficit conditions. Additionally, the cross combinations P₂ × P₄, P₃ × P₅, P₃ × P₈, and P₆ × P₇ were the most promising combinations to increase yield traits and multiple physiological parameters under water deficit conditions. Furthermore, P₁, P₂, and P₅ were recognized as promising parents to improve grain protein content and wet and dry gluten contents under drought stress. In addition, the crosses P₁ × P₄, P₂ × P₃, P₂ × P₅, P₂ × P₆, P₄ × P₇, P₅ × P₇, P₅ × P₈, P₆ × P₈, and P₇ × P₈ were the best combinations to improve grain protein content under water-stressed and non-stressed conditions. Certain physiological traits displayed highly positive associations with grain yield and its contributing traits under drought stress such as chlorophyll a, chlorophyll b, total chlorophyll content, photosynthetic efficiency (Fv/Fm), proline content, and relative water content, which suggest their importance for indirect selection under water deficit conditions. Otherwise, grain protein content was negatively correlated with grain yield, indicating that selection for higher grain yield could reduce grain protein content under drought stress conditions. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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19 pages, 2283 KiB

Open AccessArticle

Collaborative Impact of Compost and Beneficial Rhizobacteria on Soil Properties, Physiological Attributes, and Productivity of Wheat Subjected to Deficit Irrigation in Salt Affected Soil

by Alaa El-Dein Omara, Emad M. Hafez, Hany S. Osman, Emadeldeen Rashwan, Mohamed A. A. El-Said, Khadiga Alharbi, Diaa Abd El-Moneim and Salah M. Gowayed

Plants 2022, 11(7), 877; https://doi.org/10.3390/plants11070877 - 25 Mar 2022

Cited by 31 | Viewed by 3494

Abstract

Plant growth and crop productivity under unfavorable environmental challenges require a unique strategy to scavenge the severely negative impacts of these challenges such as soil salinity and water stress. Compost and plant growth-promoting rhizobacteria (PGPR) have many beneficial impacts, particularly in plants exposed [...] Read more.

Plant growth and crop productivity under unfavorable environmental challenges require a unique strategy to scavenge the severely negative impacts of these challenges such as soil salinity and water stress. Compost and plant growth-promoting rhizobacteria (PGPR) have many beneficial impacts, particularly in plants exposed to different types of stress. Therefore, a field experiment during two successive seasons was conducted to investigate the impact of compost and PGPR either separately or in a combination on exchangeable sodium percentage (ESP), soil enzymes (urease and dehydrogenase), wheat physiology, antioxidant defense system, growth, and productivity under deficient irrigation and soil salinity conditions. Our findings showed that exposure of wheat plants to deficit irrigation in salt-affected soil inhibited wheat growth and development, and eventually reduced crop productivity. However, these injurious impacts were diminished after soil amendment using the combined application of compost and PGPR. This combined application enhanced soil urease and dehydrogenase, ion selectivity, chlorophylls, carotenoids, stomatal conductance, and the relative water content (RWC) whilst reducing ESP, proline content, which eventually increased the yield-related traits of wheat plants under deficient irrigation conditions. Moreover, the coupled application of compost and PGPR reduced the uptake of Na and resulted in an increment in superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) activities that lessened oxidative damage and improved the nutrient uptake (N, P, and K) of deficiently irrigated wheat plants under soil salinity. It was concluded that to protect wheat plants from environmental stressors, such as water stress and soil salinity, co-application of compost with PGPR was found to be effective. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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Review

Jump to: Research

35 pages, 1207 KiB

Open AccessEditor’s ChoiceReview

Candidate Genes Associated with Abiotic Stress Response in Plants as Tools to Engineer Tolerance to Drought, Salinity and Extreme Temperatures in Wheat: An Overview

by Daniela Trono and Nicola Pecchioni

Plants 2022, 11(23), 3358; https://doi.org/10.3390/plants11233358 - 02 Dec 2022

Cited by 11 | Viewed by 4006

Abstract

Wheat represents one of the most important staple food crops worldwide and its genetic improvement is fundamental to meeting the global demand of the growing population. However, the environmental stresses, worsened by climate change, and the increasing deterioration of arable land make it [...] Read more.

Wheat represents one of the most important staple food crops worldwide and its genetic improvement is fundamental to meeting the global demand of the growing population. However, the environmental stresses, worsened by climate change, and the increasing deterioration of arable land make it very difficult to fulfil this demand. In light of this, the tolerance of wheat to abiotic stresses has become a key objective of genetic improvement, as an effective strategy to ensure high yields without increasing the cultivated land. Genetic erosion related to modern agriculture, whereby elite, high-yielding wheat varieties are the product of high selection pressure, has reduced the overall genetic diversity, including the allelic diversity of genes that could be advantageous for adaptation to adverse environmental conditions. This makes traditional breeding a less effective or slower approach to generating new stress-tolerant wheat varieties. Either mining for the diversity of not-adapted large germplasm pools, or generating new diversity, are the mainstream approaches to be pursued. The advent of genetic engineering has opened the possibility to create new plant variability and its application has provided a strong complement to traditional breeding. Genetic engineering strategies such as transgenesis and genome editing have then provided the opportunity to improve environmental tolerance traits of agronomic importance in cultivated species. As for wheat, several laboratories worldwide have successfully produced transgenic wheat lines with enhanced tolerance to abiotic stresses, and, more recently, significant improvements in the CRISPR/Cas9 tools available for targeted variations within the wheat genome have been achieved. In light of this, the present review aims to provide successful examples of genetic engineering applications for the improvement of wheat adaptation to drought, salinity and extreme temperatures, which represent the most frequent and most severe events causing the greatest losses in wheat production worldwide. Full article

(This article belongs to the Special Issue Responses of Wheat to Abiotic Stress)

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