The Mode of Cytokinin Functions Assisting Plant Adaptations to Osmotic Stresses

Plants respond to abiotic stresses by activating a specific genetic program that supports survival by developing robust adaptive mechanisms. This leads to accelerated senescence and reduced growth, resulting in negative agro-economic impacts on crop productivity. Cytokinins (CKs) customarily regulate various biological processes in plants, including growth and development. In recent years, cytokinins have been implicated in adaptations to osmotic stresses with improved plant growth and yield. Endogenous CK content under osmotic stresses can be enhanced either by transforming plants with a bacterial isopentenyl transferase (IPT) gene under the control of a stress inducible promoter or by exogenous application of synthetic CKs. CKs counteract osmotic stress-induced premature senescence by redistributing soluble sugars and inhibiting the expression of senescence-associated genes. Elevated CK contents under osmotic stress antagonize abscisic acid (ABA) signaling and ABA mediated responses, delay leaf senescence, reduce reactive oxygen species (ROS) damage and lipid peroxidation, improve plant growth, and ameliorate osmotic stress adaptability in plants.

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Synergetic Effects of Zinc, Boron, Silicon, and Zeolite Nanoparticles on Confer Tolerance in Potato Plants Subjected to Salinity

Agronomy ◽

10.3390/agronomy10010019 ◽

2019 ◽

Vol 10 (1) ◽

pp. 19 ◽

Cited By ~ 4

Author(s):

Abdel Wahab M. Mahmoud ◽

Emad A. Abdeldaym ◽

Suzy M. Abdelaziz ◽

Mohamed B. I. El-Sawy ◽

Shady A. Mottaleb

Keyword(s):

Plant Growth ◽

Salinity Stress ◽

Soil Salinity ◽

Field Experiments ◽

Solanum Tuberosum L ◽

Crop Productivity ◽

Growth And Yield ◽

Soil Application ◽

Potato Plants ◽

Combined Application

Salinity stress is a severe environmental stress that affects plant growth and productivity of potato, a strategic crop moderately sensitive to saline soils. Limited studies are available on the use of combined nano-micronutrients to ameliorate salinity stress in potato plants (Solanum tuberosum L.). Two open field experiments were conducted in salt-affected sandy soil to investigate plant growth, physiology, and yield of potato in response to soil salinity stress under single or combined application of Zn, B, Si, and Zeolite nanoparticles. It was hypothesized that soil application of nanoparticles enhanced plant growth and yield by alleviating the adverse impact of soil salinity. In general, all the nano-treatments applications significantly increased plant height, shoot dry weight, number of stems per plant, leaf relative water content, leaf photosynthetic rate, leaf stomatal conductance, chlorophyll content, and tuber yield, as compared to the untreated control. Furthermore, soil application of these treatments increased the concentration of nutrients (N, P, K, Ca, Zn, and B) in plant tissues, leaf proline, and leaf gibberellic acid hormone (GA3) in addition to contents of protein, carbohydrates, and antioxidant enzymes (polyphenol oxidase (PPO) and peroxidase (POD) in tubers. Compared to other treatments, the combined application of nanoparticles showed the highest plant growth, physiological parameters, endogenous elements (N, P, K, Ca, Zn, and B) and the lowest concentration of leaf abscisic acid (ABA) and transpiration rate. The present findings suggest that soil addition of the aforementioned nanoparticles can be a promising approach to improving crop productivity in salt-affected soils.

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Overview of the Role of Rhizobacteria in Plant Salt Stress Tolerance

Agronomy ◽

10.3390/agronomy11091759 ◽

2021 ◽

Vol 11 (9) ◽

pp. 1759

Author(s):

Miguel Ayuso-Calles ◽

José David Flores-Félix ◽

Raúl Rivas

Keyword(s):

Salt Stress ◽

Plant Growth ◽

Osmotic Stress ◽

Nutrient Deficiency ◽

Cost Effective ◽

Growth And Yield ◽

Soil Conditions ◽

Saline Stress ◽

Plant Growth Promoting Bacteria ◽

Plant Tolerance

Salinity is one of the main causes of abiotic stress in plants, resulting in negative effects on crop growth and yield, especially in arid and semi-arid regions. The effects of salinity on plant growth mainly generate osmotic stress, ion toxicity, nutrient deficiency, and oxidative stress. Traditional approaches for the development of salt-tolerant crops are expensive and time-consuming, as well as not always being easy to implement. Thus, the use of plant growth-promoting bacteria (PGPB) has been reported as a sustainable and cost-effective alternative to enhance plant tolerance to salt stress. In this sense, this review aims to understand the mechanisms by which PGPB help plants to alleviate saline stress, including: (i) changes in the plant hormonal balance; (ii) release of extracellular compounds acting as chemical signals for the plant or enhancing soil conditions for plant development; (iii) regulation of the internal ionic content of the plant; or iv) aiding in the synthesis of osmoprotectant compounds (which reduce osmotic stress). The potential provided by PGPB is therefore an invaluable resource for improving plant tolerance to salinity, thereby facilitating an increase in global food production and unravelling prospects for sustainable agricultural productivity.

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The role of ACC deaminase producing bacteria in improving sweet corn (Zea mays L. var saccharata) productivity under limited availability of irrigation water

Scientific Reports ◽

10.1038/s41598-020-77305-6 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tayebeh Zarei ◽

Ali Moradi ◽

Seyed Abdolreza Kazemeini ◽

Abdolreza Akhgar ◽

Ashfaq Ahmad Rahi

Keyword(s):

Zea Mays ◽

Osmotic Stress ◽

Seed Yield ◽

Irrigation Water ◽

Sweet Corn ◽

Soluble Sugars ◽

Growth And Yield ◽

Production Plant ◽

Promoting Effect ◽

Limited Availability

AbstractAccumulation of stress ethylene in plants due to osmotic stress is a major challenge for the achievement of optimum sweet corn crop yield with limited availability of irrigation water. A significant increase in earth’s temperature is also making the conditions more crucial regarding the availability of ample quantity of irrigation water for crops production. Plant growth promoting rhizobacteria (PGPR) can play an imperative role in this regard. Inoculation of rhizobacteria can provide resistance and adaptability to crops against osmotic stress. In addition, these rhizobacteria also have potential to solve future food security issues. That's why the current study was planned to examine the efficacious functioning of Pseudomonas fluorescens strains on yields and physiological characteristics of sweet corn (Zea mays L. var saccharata) under different levels of irrigation. Three irrigation levels i.e., 100% (I100 no stress), 80% (I80), and 60% (I60) were used during sweet corn cultivation. However, there were four rhizobacteria strains i.e., P. fluorescens P1, P. fluorescens P3, P. fluorescens P8, P. fluorescens P14 which were used in the experiment. The results showed that severe water stress (60% of plant water requirement) decreased chlorophyll a, chlorophyll b, and total chlorophyll contents, Fv/Fm ratio and nutrients uptake. A significant increase in F0, Fm, proline, total soluble sugars, catalase (CAT) and peroxidase (POX) activity led to less ear yield and canned seed yield. Combination of four strains significantly increased the yield traits of sweet corn i.e., ear and (44%) and canned seed yield (27%) over control. The highest promoting effect was observed in the combination of four strains treatment and followed by P1 strain in reducing the harmful effects of drought stress and improving sweet corn productivity. However, P14 gave minimum improvement in growth and yield indices under limited availability of water. In conclusion, combination of four strains inoculation is an efficacious approach for the achievement of better yield of sweet corn under osmotic stress.

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Physiological and growth responses of two wheat (Triticum aestivum L.) varieties inoculated with a new strain of Bacillus siamensis under Cadmium (Cd) stress

10.21203/rs.3.rs-22644/v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Imran Khan ◽

Huang Linkai ◽

Samrah Afzal Awan ◽

Abd ur Rehman ◽

Muhammad Ali Raza ◽

...

Keyword(s):

Triticum Aestivum ◽

Plant Growth ◽

Soluble Sugars ◽

Membrane Damage ◽

Growth And Yield ◽

Tolerance Index ◽

Photosynthetic Parameters ◽

World Population ◽

Growth Responses ◽

Cd Stress

Abstract Bioavailability of cadmium (Cd) metal in the soils due to scarcity of good quality water and industrial waste could be the major limiting factors negatively influencing the growth and yield of crops needs prompt solution to fulfil the requirement of food for increasing world population. In the recent time, variable range of plant growth promoting rhizobacteria (PGPR) are being used on large scale in agriculture to reduce the risk of abiotic stresses on plants and increase crop productivity. Among them, the Bacillus siamensis has a huge potential to enhance the plant tolerance against abiotic stress but limited evidences are reported about the putative role of B.s in crop plants under heavy metal stress. The current study was aimed to investigate the potential of a new metal tolerant strain of B.s on two wheat (Triticum aestivum L.) varieties (NARC-2009 and NARC-2011) grown in Cd contaminated soil at different treatments i.e Cd (0, 20, 30 and 50 ppm) and Cd (0, 20, 30 and 50 ppm) + B.s. Our results depicted that Cd stress decreased the wheat growth related attributes, biomass, and photosynthetic parameters (Chlorophyll a, b and a + b) which increased in both wheat varieties upon inoculation with B.s. Moreover, Cd stress caused significant membrane damage and negatively affected the water content, water potential, and osmotic potential of leaf. However, PGPR considerably increased the soluble sugars to reduce the Cd toxicity. Overall, the plants inoculated with B.s enhanced their tolerance index of root and shoot and found better in NARC-2009 than NARC-2011. Therefore, microorganisms efficiently increase the plant growth by reducing the metal toxicity.

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The Integration of Bio and Organic Fertilizers Improve Plant Growth, Grain Yield, Quality and Metabolism of Hybrid Maize (Zea mays L.)

Agronomy ◽

10.3390/agronomy10030319 ◽

2020 ◽

Vol 10 (3) ◽

pp. 319 ◽

Cited By ~ 3

Author(s):

Canhong Gao ◽

Ahmed M. El-Sawah ◽

Dina Fathi Ismail Ali ◽

Yousef Alhaj Hamoud ◽

Hiba Shaghaleh ◽

...

Keyword(s):

Plant Growth ◽

Soluble Sugars ◽

Growth Yield ◽

Organic Fertilizers ◽

Growth And Yield ◽

Bacillus Circulans ◽

Organic Fertilization ◽

Chemical Fertilizers ◽

Maize Growth ◽

Hybrid Maize

Expanding eco-friendly approaches to improve plant growth and crop productivity is of great important for sustainable agriculture. Therefore, a field experiment was carried out at the Faculty of Agriculture Farm, Mansoura University, Egypt during the 2018 and 2019 growing seasons to study the effects of different bio- and organic fertilizers and their combination on hybrid maize growth, yield, and grain quality. Seeds were treated with Azotobacter chrocoocum, arbuscular mycorrhizal fungi (AMF), Bacillus circulans, biogas slurry, humic acid (HA), and their combination aiming to increase the growth and yield of maize and to reduce the need for chemical fertilizers. The results showed that combined application of the biofertilizer mixture (Azotobacter chrocoocum, AMF, and Bacillus circulans) with organic fertilizers enhanced maize growth, yield, and nutrient uptake. Moreover, the bio-organic fertilization has improved the soluble sugars, starch, carbohydrates, protein, and amino acid contents in maize seeds. Additionally, the bio-organic fertilization caused an obvious increase in the microbial activity by enhancing acid phosphatase and dehydrogenase enzymes, bacterial count, and mycorrhizal colonization levels in maize rhizosphere as compared with the chemical fertilization. Additionally, the bio-organic fertilizers has improved α-amylase and gibberellins (GA) activities and their transcript levels, as well as decreased the abscisic acid (ABA) level in the seeds as compared to the chemical fertilizers. The obtained results of bio-organic fertilization on the growth parameters and yield of maize recommend their use as an alternative tool to reduce chemical fertilizers.

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Down Regulation and Loss of Auxin Response Factor 4 Function Using CRISPR/Cas9 Alters Plant Growth, Stomatal Function and Improves Tomato Tolerance to Salinity and Osmotic Stress

Genes ◽

10.3390/genes11030272 ◽

2020 ◽

Vol 11 (3) ◽

pp. 272 ◽

Cited By ~ 6

Author(s):

Sarah Bouzroud ◽

Karla Gasparini ◽

Guojian Hu ◽

Maria Antonia Machado Barbosa ◽

Bruno Luan Rosa ◽

...

Keyword(s):

Plant Growth ◽

Osmotic Stress ◽

Stress Responses ◽

Target Genes ◽

Soluble Sugars ◽

Auxin Response ◽

Down Regulation ◽

Aba Content ◽

Tolerance To Salinity ◽

Salt And Osmotic Stress

Auxin controls multiple aspects of plant growth and development. However, its role in stress responses remains poorly understood. Auxin acts on the transcriptional regulation of target genes, mainly through Auxin Response Factors (ARF). This study focuses on the involvement of SlARF4 in tomato tolerance to salinity and osmotic stress. Using a reverse genetic approach, we found that the antisense down-regulation of SlARF4 promotes root development and density, increases soluble sugars content and maintains chlorophyll content at high levels under stress conditions. Furthermore, ARF4-as displayed higher tolerance to salt and osmotic stress through reduced stomatal conductance coupled with increased leaf relative water content and Abscisic acid (ABA) content under normal and stressful conditions. This increase in ABA content was correlated with the activation of ABA biosynthesis genes and the repression of ABA catabolism genes. Cu/ZnSOD and mdhar genes were up-regulated in ARF4-as plants which can result in a better tolerance to salt and osmotic stress. A CRISPR/Cas9 induced SlARF4 mutant showed similar growth and stomatal responses as ARF4-as plants, which suggest that arf4-cr can tolerate salt and osmotic stresses. Our data support the involvement of ARF4 as a key factor in tomato tolerance to salt and osmotic stresses and confirm the use of CRISPR technology as an efficient tool for functional reverse genetics studies.

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Plant growth promoting rhizobacteria alleviates drought stress in potato in response to suppressive oxidative stress and antioxidant enzymes activities

Scientific Reports ◽

10.1038/s41598-020-73489-z ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tahira Batool ◽

Shafaqat Ali ◽

Mahmoud F. Seleiman ◽

Naima Huma Naveed ◽

Aamir Ali ◽

...

Keyword(s):

Growth Rate ◽

Drought Stress ◽

Plant Growth ◽

Relative Growth Rate ◽

Soluble Sugars ◽

Plant Growth Promoting Rhizobacteria ◽

Growth And Yield ◽

Relative Growth ◽

Relative Water ◽

Plant Growth Promoting

Abstract Maintenance of plant physiological functions under drought stress is normally considered a positive feature as it indicates sustained plant health and growth. This study was conducted to investigate whether plant growth-promoting rhizobacteria (PGPR) Bacillus subtilis HAS31 has potential to maintain potato growth and yield under drought stress. We analyzed trends of chlorophyll concentration, photosynthesis process, relative water content, osmolytes, antioxidants enzymes and oxidative stress, relative growth rate, tuber and aboveground biomass production in two potato varieties, Santae (drought-tolerant) and PRI-Red (drought-sensitive). Plants of both genotypes were treated with 100 g of HAS31 inoculant at 10 days after germination and exposed to different soil relative water contents (SRWC), including 80 ± 5% (well watered), 60 ± 5% (moderate stress) and 40 ± 5% SRWC (severe stress) for 7 days at tuber initiation stage (30 days after germination). The drought stress reduced plant relative growth rate, biomass production, leaf area, number of leaves and tubers, tuber weight, and final yield. The drought-stressed plants showed decline in chlorophyll contents, membrane stability, leaf relative water contents and photosynthetic rate. Under drought stress, enzymatic activity of catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD), contents of total soluble sugars, soluble proteins and proline increased. The application of PGPR reduced the impact of drought and maintained higher growth and physio-chemical traits of the plants. The plants with PGPR application showed higher relative growth rate, dry matter production, leaf area, number of tubers, tuber weight and yield as compared to plants without PGPR. The PGPR-HAS31 treated plants maintained higher photosynthetic process, contents of chlorophyll, soluble proteins, total soluble sugars, and enzymatic activities of CAT, POD and SOD as compared to plants without PGPR. The results of the study suggest that plant growth regulators have ability to sustain growth and yield of potato under drought stress by maintaining physiological functions of the plants.

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Harnessing Trichoderma in Agriculture for Productivity and Sustainability

Agronomy ◽

10.3390/agronomy11122559 ◽

2021 ◽

Vol 11 (12) ◽

pp. 2559

Author(s):

Nur Syafikah Abdullah ◽

Febri Doni ◽

Muhamad Shakirin Mispan ◽

Mohd Zuwairi Saiman ◽

Yusmin Mohd Yusuf ◽

...

Keyword(s):

Plant Growth ◽

Abiotic Stresses ◽

Crop Production ◽

Environmental Changes ◽

Crop Productivity ◽

Plant Production ◽

Growth And Yield ◽

Great Promise ◽

Biotic And Abiotic Stresses ◽

The Impact

Increased agricultural activities driven by rising food demand have led to environmental problems mostly arising from the high levels of external inputs and resources that are required. Additionally, environmental changes, such as global warming, can lead to various biotic and abiotic stresses, which have negative impacts on crop production. Numerous solutions and agricultural strategies have been introduced to overcome these problems. One of the ways to improve plant production as well as to increase resistance towards biotic and abiotic stresses is by utilizing beneficial microbes as soil inoculants. A better understanding of the ability of Trichoderma to enhance crop production and the mechanisms that are involved are important for deriving maximum benefits from their exploitation. These versatile fungi hold great promise for the development of viable commercial products that can be used widely in agriculture for increasing crop productivity in a more sustainable way. Many previous reviews on Trichoderma have tended to focus on the mechanisms of Trichoderma in enhancing plant growth and yield. This current review discusses the sustainability aspect of using Trichoderma as plant growth regulators, the impact on plant growth and yield as well as their effects in regulating biotic and abiotic stresses.

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The Effects of Biochar and Its Combination with Compost on Lettuce (Lactuca sativaL.) Growth, Soil Properties, and Soil Microbial Activity and Abundance

International Journal of Agronomy ◽

10.1155/2017/3158207 ◽

2017 ◽

Vol 2017 ◽

pp. 1-12 ◽

Cited By ~ 33

Author(s):

Dalila Trupiano ◽

Claudia Cocozza ◽

Silvia Baronti ◽

Carla Amendola ◽

Francesco Primo Vaccari ◽

...

Keyword(s):

Plant Growth ◽

Organic Fertilizer ◽

Crop Productivity ◽

Total Carbon ◽

Growth And Yield ◽

Chemical Characteristics ◽

Total Biomass ◽

Nitrogen And Phosphorus ◽

Positive Effects ◽

Compost Amendment

Impacts of biochar application in combination with organic fertilizer, such as compost, are not fully understood. In this study, we tested the effects of biochar amendment, compost addition, and their combination on lettuce plants grown in a soil poor in nutrients; soil microbiological, chemical, and physical characteristics were analyzed, together with plant growth and physiology. An initial screening was also done to evaluate the effect of biochar and compost toxicity, using cress plants and earthworms. Results showed that compost amendment had clear and positive effects on plant growth and yield and on soil chemical characteristics. However, we demonstrated that also the biochar alone stimulated lettuce leaves number and total biomass, improving soil total nitrogen and phosphorus contents, as well as total carbon, and enhancing related microbial communities. Nevertheless, combining biochar and compost, no positive synergic and summative effects were observed. Our results thus demonstrate that in a soil poor in nutrients the biochar alone could be effectively used to enhance soil fertility and plant growth and biomass yield. However, we can speculate that the combination of compost and biochar may enhance and sustain soil biophysical and chemical characteristics and improve crop productivity over time.

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Role of Raf-like kinases in SnRK2 activation and osmotic stress response in plants

Nature Communications ◽

10.1038/s41467-020-19977-2 ◽

2020 ◽

Vol 11 (1) ◽

Author(s):

Norma Fàbregas ◽

Takuya Yoshida ◽

Alisdair R. Fernie

Keyword(s):

Osmotic Stress ◽

High Salinity ◽

Plant Stress ◽

Crop Productivity ◽

Growth And Yield ◽

Signalling Pathways ◽

Evolutionary Perspective ◽

Signalling Network ◽

Osmotic Stress Response

AbstractEnvironmental drought and high salinity impose osmotic stress, which inhibits plant growth and yield. Thus, understanding how plants respond to osmotic stress is critical to improve crop productivity. Plants have multiple signalling pathways in response to osmotic stress in which the phytohormone abscisic acid (ABA) plays important roles. However, since little is known concerning key early components, the global osmotic stress-signalling network remains to be elucidated. Here, we review recent advances in the identification of osmotic-stress activated Raf-like protein kinases as regulators of ABA-dependent and -independent signalling pathways and discuss the plant stress-responsive kinase network from an evolutionary perspective.

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