30 results on '"Pushp Sheel Shukla"'
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2. A red seaweed Kappaphycus alvarezii-based biostimulant (AgroGain®) improves the growth of Zea mays and impacts agricultural sustainability by beneficially priming rhizosphere soil microbial community
- Author
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Nagarajan Nivetha, Pushp Sheel Shukla, Sri Sailaja Nori, Sawan Kumar, and Shrikumar Suryanarayan
- Subjects
sustainable agriculture ,red seaweed-based biostimulants ,Kappaphycus alvarezii ,metagenome ,rhizosphere microbiome ,soil health ,Microbiology ,QR1-502 - Abstract
The overuse of chemical-based agricultural inputs has led to the degradation of soil with associated adverse effects on soil attributes and microbial population. This scenario leads to poor soil health and is reportedly on the rise globally. Additionally, chemical fertilizers pose serious risks to the ecosystem and human health. In this study, foliar sprays of biostimulant (AgroGain/LBS6) prepared from the cultivated, tropical red seaweed Kappaphycus alvarezii increased the phenotypic growth of Zea mays in terms of greater leaf area, total plant height, and shoot fresh and dry weights. In addition, LBS6 improved the accumulation of chlorophyll a and b, total carotenoids, total soluble sugars, amino acids, flavonoids, and phenolics in the treated plants. LBS6 applications also improved the total bacterial and fungal count in rhizospheric soil. The V3-V4 region of 16S rRNA gene from the soil metagenome was analyzed to study the abundance of bacterial communities which were increased in the rhizosphere of LBS6-treated plants. Treatments were found to enrich beneficial soil bacteria, i.e., Proteobacteria, especially the classes Alphaproteobacteria, Cyanobacteria, Firmicutes, Actinobacteriota, Verrucomicrobiota, Chloroflexi, and Acidobacteriota and several other phyla related to plant growth promotion. A metagenomic study of those soil samples from LBS6-sprayed plants was correlated with functional potential of soil microbiota. Enrichment of metabolisms such as nitrogen, sulfur, phosphorous, plant defense, amino acid, co-factors, and vitamins was observed in soils grown with LBS6-sprayed plants. These results were further confirmed by a significant increase in the activity of soil enzymes such as urease, acid phosphatase, FDAse, dehydrogenase, catalase, and biological index of fertility in the rhizosphere of LBS6-treated corn plant. These findings conclude that the foliar application of LBS6 on Z. mays improves and recruits beneficial microbes and alters soil ecology in a sustainable manner.
- Published
- 2024
- Full Text
- View/download PDF
3. A biostimulant prepared from red seaweed Kappaphycus alvarezii induces flowering and improves the growth of Pisum sativum grown under optimum and nitrogen-limited conditions
- Author
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Pushp Sheel Shukla, Nagarajan Nivetha, Sri Sailaja Nori, Sawan Kumar, Alan T. Critchley, and Shrikumar Suryanarayan
- Subjects
Kappaphycus alvarezii ,biostimulants ,nitrogen metabolism ,gene expression ,Pisum sativum ,sustainable agriculture ,Plant culture ,SB1-1110 - Abstract
Nitrogen (N) is one of the critical elements required by plants and is therefore one of the important limiting factors for growth and yield. To increase agricultural productivity, farmers are using excessive N fertilizers to the soil, which poses a threat to the ecosystem, as most of the applied nitrogen fertilizer is not taken up by crops, and runoff to aquatic bodies and the environment causes eutrophication, pollution, and greenhouse gas emissions. In this study, we used LBS6, a Kappaphycus alvarezii-based biostimulant as a sustainable alternative to improve the growth of plants under different NO3- fertigation. A root drench treatment of 1 ml/L LBS6 significantly improved the growth of Pisum sativum plants grown under optimum and deficient N conditions. No significant difference was observed in the growth of LBS6-treated plants grown with excessive N. The application of LBS6 induced flowering under optimum and deficient N conditions. The total nitrogen, nitrate and ammonia contents of tissues were found to be higher in treated plants grown under N deficient conditions. The LBS6 treatments had significantly higher chlorophyll content in those plants grown under N-deficient conditions. The root drench application of LBS6 also regulated photosynthetic efficiency by modulating electron and proton transport-related processes of leaves in the light-adapted state. The rate of linear electron flux, proton conductivity and steady-state proton flux across the thylakoid membrane were found to be higher in LBS6-treated plants. Additionally, LBS6 also reduced nitrogen starvation-induced, reactive oxygen species accumulation by reduction in lipid peroxidation in treated plants. Gene expression analysis showed differential regulation of expression of those genes involved in N uptake, transport, assimilation, and remobilization in LBS6-treated plants. Taken together, LBS6 improved growth of those treated plants under optimum and nitrogen-limited condition by positively modulating their biochemical, molecular, and physiological processes.
- Published
- 2024
- Full Text
- View/download PDF
4. Understanding the mode of action of AgroGain®, a biostimulant derived from the red seaweed Kappaphycus alvarezii in the stimulation of cotyledon expansion and growth of Cucumis sativa (cucumber)
- Author
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Pushp Sheel Shukla, Nagarajan Nivetha, Sri Sailaja Nori, Debayan Bose, Sawan Kumar, Sachin Khandelwal, Alan Critchley, and Shrikumar Suryanarayan
- Subjects
Kappaphycus alvarezii ,seaweed-based biostimulants ,plant growth ,cucumber ,photosynthesis ,Plant culture ,SB1-1110 - Abstract
Seaweed-based biostimulants are sustainable agriculture inputs that are known to have a multitude of beneficial effects on plant growth and productivity. This study demonstrates that Agrogain® (Product code: LBS6), a Kappaphycus alvarezii-derived biostimulant induced the expansion of cucumber cotyledons. Seven days treatment of LBS6-supplementation showed a 29.2% increase in area of expanded cotyledons, as compared to the control. LBS6-treated cotyledons also showed higher amylase activity, suggesting starch to sucrose conversion was used efficiently as an energy source during expansion. To understand the mechanisms of LBS6-induced expansion, real time gene expression analysis was carried out. This revealed that LBS6-treated cotyledons differentially modulated the expression of genes involved in cell division, cell number, cell expansion and cell size. LBS6 treatment also differentially regulated the expression of those genes involved in auxin and cytokinin metabolism. Further, foliar application of LBS6 on cucumber plants being grown under hydroponic conditions showed improved plant growth as compared to the control. The total leaf area of LBS6-sprayed plants increased by 19.1%, as compared to control. LBS6-sprayed plants efficiently regulated photosynthetic quenching by reducing loss via non-photochemical and non-regulatory quenching. LBS6 applications also modulated changes in the steady-state photosynthetic parameters of the cucumber leaves. It was demonstrated that LBS6 treatment modulated the electron and proton transport related pathways which help plants to efficiently utilize the photosynthetic radiation for optimal growth. These results provide clear evidence that bioactive compounds present in LBS6 improved the growth of cucumber plants by regulating the physiological as well as developmental pathways.
- Published
- 2023
- Full Text
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5. Editorial: Biostimulants as an Avenue of Abiotic Stress Tolerance Improvement in Crops
- Author
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Pushp Sheel Shukla, Narendra Singh Yadav, Alan T. Critchley, and Balakrishnan Prithiviraj
- Subjects
biostimulants ,sustainable agriculture ,microbial biostimulant ,seaweed based biostimulants ,plant growth and stress tolerance ,Nutrition. Foods and food supply ,TX341-641 ,Food processing and manufacture ,TP368-456 - Published
- 2022
- Full Text
- View/download PDF
6. A Biostimulant Preparation of Brown Seaweed Ascophyllum nodosum Suppresses Powdery Mildew of Strawberry
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Sruti Bajpai, Pushp Sheel Shukla, Samuel Asiedu, Kris Pruski, and Balakrishnan Prithiviraj
- Subjects
Ascophyllum nodosum extract ,phenylalanine ammonia lyase ,Podosphaera aphanis ,powdery mildew ,strawberry ,Plant culture ,SB1-1110 - Abstract
Strawberry, an important fruit crop, is susceptible to a large number of pathogens that reduce fruit quality and productivity. In this study, the effect of a biostimulant prepared from Ascophyllum nodosum extract (ANE) (0.1%, 0.2%, and 0.3%) was evaluated on powdery mildew progression under greenhouse and field conditions. In the greenhouse, application of 0.2% ANE showed maximum reduction in powdery mildew progression as compared to the control. Forty-eight hour post-inoculation, foliar spray of 0.2% ANE reduced spore germination by 75%. Strawberry leaves sprayed with ANE showed higher total phenolic and flavonoid content in response to powdery mildew infection. Furthermore, application of ANE elicited defense response in strawberry plants by induction of defense-related enzymes, such as phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase activity. In field conditions, foliar spray of 0.2% ANE showed a reduction of 37.2% of natural incidence of powdery mildew infection as compared to the control. ANE sprayed plant also reduces the severity of powdery mildew infection under natural conditions. These results indicate that application of ANE induces the strawberry plant's active defense against powdery mildew infection by induction of secondary metabolism and regulating the activities of defense-related enzymes.
- Published
- 2019
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7. Ascophyllum nodosum Biostimulant Improves the Growth of Zea mays Grown Under Phosphorus Impoverished Conditions
- Author
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Pushp Sheel Shukla and Balakrishnan Prithiviraj
- Subjects
Ascophyllum nodosum extract ,P-limited condition ,chemical fertilizer ,gene expression ,Zea mays ,Plant culture ,SB1-1110 - Abstract
Phosphorous is one of the major limiting factors determining plant growth. Current agricultural practices mainly rely on the use of chemical fertilizers posing threat to the ecosystem. In this study, the application of an Ascophyllum nodosum extract (ANE) in phosphorous (P)-limited conditions improved the fresh and dry weight of shoots and roots of Zea mays. ANE-treated Z. mays grown under P-limited conditions showed a higher P content than the control. ANE activated simultaneous responses, at multiple levels, in Z. mays grown under P-limited conditions as seen from the regulation of gene expression at the whole-plant level to specific biochemical responses on a subcellular level. ANE-supplemented Z. mays grown under P-limited conditions also showed reduced electrolyte leakage and lipid peroxidation by an improved membrane stability. ANE treatment reduced P-limitation-induced oxidative damage in Z. mays by reducing H2O2 and O2- accumulation. Furthermore, ANE also induced the accumulation of the total contents of soluble sugars, amino acids, phenolics, and flavonoids. Gene expression analysis suggested that ANE differentially modulated the expression of P-starvation responsive genes involved in metabolic, signal transduction, and developmental pathways in Z. mays. ANE also modulated the expression of genes involved in sugar, lipid, and secondary metabolism. Thus, this study illustrated the role of ANE in improving the productivity of Z. mays, an important crop, in P-limited conditions. Furthermore, it sets the framework to increase agricultural productivity in nutrient deficient soils using a sustainable, eco-friendly strategy.
- Published
- 2021
- Full Text
- View/download PDF
8. Ascophyllum nodosum-Based Biostimulants: Sustainable Applications in Agriculture for the Stimulation of Plant Growth, Stress Tolerance, and Disease Management
- Author
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Pushp Sheel Shukla, Emily Grace Mantin, Mohd Adil, Sruti Bajpai, Alan T. Critchley, and Balakrishnan Prithiviraj
- Subjects
Ascophyllum nodosum ,biostimulants ,plant growth ,stress tolerance ,disease management ,Plant culture ,SB1-1110 - Abstract
Abiotic and biotic stresses limit the growth and productivity of plants. In the current global scenario, in order to meet the requirements of the ever-increasing world population, chemical pesticides and synthetic fertilizers are used to boost agricultural production. These harmful chemicals pose a serious threat to the health of humans, animals, plants, and the entire biosphere. To minimize the agricultural chemical footprint, extracts of Ascophyllum nodosum (ANE) have been explored for their ability to improve plant growth and agricultural productivity. The scientific literature reviewed in this article attempts to explain how certain bioactive compounds present in extracts aid to improve plant tolerances to abiotic and/or biotic stresses, plant growth promotion, and their effects on root/microbe interactions. These reports have highlighted the use of various seaweed extracts in improving nutrient use efficiency in treated plants. These studies include investigations of physiological, biochemical, and molecular mechanisms as evidenced using model plants. However, the various modes of action of A. nodosum extracts have not been previously reviewed. The information presented in this review depicts the multiple, beneficial effects of A. nodosum-based biostimulant extracts on plant growth and their defense responses and suggests new opportunities for further applications for marked benefits in production and quality in the agriculture and horticultural sectors.
- Published
- 2019
- Full Text
- View/download PDF
9. Seaweed-Based Compounds and Products for Sustainable Protection against Plant Pathogens
- Author
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Pushp Sheel Shukla, Tudor Borza, Alan T. Critchley, and Balakrishnan Prithiviraj
- Subjects
biostimulants ,seaweed ,bioactive compounds ,plant pathogens ,Biology (General) ,QH301-705.5 - Abstract
Sustainable agricultural practices increasingly demand novel, environmentally friendly compounds which induce plant immunity against pathogens. Stimulating plant immunity using seaweed extracts is a highly viable strategy, as these formulations contain many bio-elicitors (phyco-elicitors) which can significantly boost natural plant immunity. Certain bioactive elicitors present in a multitude of extracts of seaweeds (both commercially available and bench-scale laboratory formulations) activate pathogen-associated molecular patterns (PAMPs) due to their structural similarity (i.e., analogous structure) with pathogen-derived molecules. This is achieved via the priming and/or elicitation of the defense responses of the induced systemic resistance (ISR) and systemic acquired resistance (SAR) pathways. Knowledge accumulated over the past few decades is reviewed here, aiming to explain why certain seaweed-derived bioactives have such tremendous potential to elicit plant defense responses with considerable economic significance, particularly with increasing biotic stress impacts due to climate change and the concomitant move to sustainable agriculture and away from synthetic chemistry and environmental damage. Various extracts of seaweeds display remarkably different modes of action(s) which can manipulate the plant defense responses when applied. This review focuses on both the similarities and differences amongst the modes of actions of several different seaweed extracts, as well as their individual components. Novel biotechnological approaches for the development of new commercial products for crop protection, in a sustainable manner, are also suggested.
- Published
- 2021
- Full Text
- View/download PDF
10. Combination of Ascophyllum nodosum Extract and Humic Acid Improve Early Growth and Reduces Post-Harvest Loss of Lettuce and Spinach
- Author
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Monica Sandepogu, Pushp Sheel Shukla, Samuel Asiedu, Svetlana Yurgel, and Balakrishnan Prithiviraj
- Subjects
biostimulants ,seaweed extract ,plant growth ,spinach ,lettuce ,post-harvest loss ,Agriculture (General) ,S1-972 - Abstract
Leafy vegetables like lettuce and spinach are prone to significant post-harvest losses during handling and storage. The pre-harvest treatment of crops with biostimulants offers a sustainable strategy for reducing post-harvest losses. Earlier studies focused on the effect of plant biostimulants applied individually. In this study, we studied the efficacy of a combined application of two commonly used plant biostimulants: Ascophyllum nodosum extract (ANE) and humic acid (HA). Interestingly, the combination of both biostimulants improved early growth of lettuce and spinach compared to ANE and HA alone. Among the combinations used in this study, 0.25% ANE + 0.2% HA produced significantly higher fresh and dry biomass in lettuce and spinach compared to the other treatments and the control. Pre-harvest treatment of combination of 0.25% ANE and 0.2% HA significantly reduced the loss of fresh biomass during post-harvest storage. The combination of 0.25% ANE and 0.2% HA reduced lipid peroxidation during storage with an increase in total ascorbate, phenolic, and antioxidant capacity of spinach and lettuce. These results suggest that a combination of ANE and HA reduces post-harvest losses of spinach and lettuce more effectively than when applied individually.
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- 2019
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11. Ascophyllum nodosum extract mitigates salinity stress in Arabidopsis thaliana by modulating the expression of miRNA involved in stress tolerance and nutrient acquisition.
- Author
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Pushp Sheel Shukla, Tudor Borza, Alan T Critchley, David Hiltz, Jeff Norrie, and Balakrishnan Prithiviraj
- Subjects
Medicine ,Science - Abstract
Ascophyllum nodosum extract (ANE) contains bioactive compounds that improve the growth of Arabidopsis in experimentally-induced saline conditions; however, the molecular mechanisms through which ANE elicits tolerance to salinity remain largely unexplored. Micro RNAs (miRNAs) are key regulators of gene expression, playing crucial roles in plant growth, development, and stress tolerance. Next generation sequencing of miRNAs from leaves of control Arabidopsis and from plants subjected to three treatments (ANE, NaCl and ANE+NaCl) was used to identify ANE-responsive miRNA in the absence and presence of saline conditions. Differential gene expression analysis revealed that ANE had a strong effect on miRNAs expression in both conditions. In the presence of salinity, ANE tended to reduce the up-regulation or the down-regulation trend induced caused by NaCl in miRNAs such as ath-miR396a-5p, ath-miR399, ath-miR2111b and ath-miR827. To further uncover the effects of ANE, the expression of several target genes of a number of ANE-responsive miRNAs was analyzed by qPCR. NaCl, but not ANE, down-regulated miR396a-5p, which negatively regulated the expression of AtGRF7 leading to a higher expression of AtDREB2a and AtRD29 in the presence of ANE+NaCl, as compared to ANE alone. ANE+NaCl initially reduced and then enhanced the expression of ath-miR169g-5p, while the expression of the target genes AtNFYA1 and ATNFYA2, known to be involved in the salinity tolerance mechanism, was increased as compared to ANE or to NaCl treatments. ANE and ANE+NaCl modified the expression of ath-miR399, ath-miR827, ath-miR2111b, and their target genes AtUBC24, AtWAK2, AtSYG1 and At3g27150, suggesting a role of ANE in phosphate homeostasis. In vivo and in vitro experiments confirmed the improved growth of Arabidopsis in presence of ANE, in saline conditions and in phosphate-deprived medium, further substantiating the influence of ANE on a variety of essential physiological processes in Arabidopsis including salinity tolerance and phosphate uptake.
- Published
- 2018
- Full Text
- View/download PDF
12. Carrageenans from red seaweeds as promoters of growth and elicitors of defense response in plants
- Author
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Pushp Sheel Shukla, Tudor eBorza, Alan T Critchley, and Balakrishnan ePrithiviraj
- Subjects
Plant Growth ,systemic acquired resistance ,plant defense mechanisms ,Carrageenans ,Plant elicitor ,plant signaling pathways ,Science ,General. Including nature conservation, geographical distribution ,QH1-199.5 - Abstract
Plants incessantly encounter abiotic and biotic stresses that limit their growth and productivity. However, conversely, plant growth can also be induced by treatments with various abiotic and biotic elicitors. Carrageenans are sulfated linear polysaccharides that represent major cellular constituents of seaweeds belonging to red algae (Rhodophyta). Recent research has unraveled the biological activity of carrageenans and of their oligomeric forms, the oligo carrageenans (OCs), as promoters of plant growth and as elicitors of defense responses against pests and diseases. In this review, we discuss the molecular mechanisms by which carrageenans and OCs mediate plant growth and plant defense responses. Carrageenans and OCs improve plant growth by regulating various metabolic processes such as photosynthesis and ancillary pathways, cell division, purine and pyrimidine synthetic pathways as well as metabolic pathways involved in nitrogen and sulfur assimilation. Carrageenans and OCs also induce plant defense responses against viroids, viruses, bacteria, fungi and insects by modulating the activity of different defense pathways, including salicylate, jasmonate and ethylene signaling pathways. Further studies will likely substantiate the beneficial effects of carrageenans and of OCs on plant growth and plant defense responses and open new avenues for their use in agriculture and horticultural industry.
- Published
- 2016
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13. An alkali-extracted biostimulant prepared from Ascophyllum nodosum alters the susceptibility of Arabidopsis thaliana to the green peach aphid
- Author
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Saveetha Kandasamy, Balakrishnan Prithiviraj, Alan T. Critchley, Chaminda De Silva Weeraddana, Pushp Sheel Shukla, and G. Christopher Cutler
- Subjects
0106 biological sciences ,Population ,macromolecular substances ,Plant Science ,Aquatic Science ,medicine.disease_cause ,01 natural sciences ,03 medical and health sciences ,stomatognathic system ,Arabidopsis ,Infestation ,medicine ,Arabidopsis thaliana ,education ,030304 developmental biology ,0303 health sciences ,Aphid ,education.field_of_study ,biology ,fungi ,food and beverages ,Plant physiology ,biology.organism_classification ,Horticulture ,Myzus persicae ,Ascophyllum ,010606 plant biology & botany - Abstract
Extracts from the brown seaweed, Ascophyllum nodosum (ANE), are extensively used as plant biostimulants. Ascophyllum nodosum extracts, as applied to plants, impart resistance/tolerance against various abiotic and biotic stresses due to the presence of multiple biological primers and elicitors. However, little information is available on the effects of ANE on insect pests of crops. Green peach aphid (GPA), Myzus persicae, is an important insect pest and used as an insect model to study insect-plant interactions. In this study, Arabidopsis thaliana was used as a model plant to determine whether application of an ANE conferred any protection from a GPA infestation. Plants treated with ANE had a 13% greater GPA population than the inorganic-treated control. Feeding preference of GPA was not influenced by ANE treatment when the insect was given a choice between the ANE-treated and control plants. Higher plant biomass was observed in ANE treatments with a GPA infestation, as compared to the control. Plants treated with ANE demonstrated better recovery from GPA infestation, as shown by a higher seed yield. Apart from higher GPA numbers, ANE-treated plants exhibited reduced plant tissue damage around the feeding area. Lower expressions of SAG13 and SAG 21 genes indicated that ANE-treated plants delayed their senescence in Arabidopsis. We concluded that treatment of ANE conferred protection from the GPA biotic pressure, while delaying senescence in treated Arabidopsis. Increased GPA numbers, on treated plants could be, in part, associated with delayed senescence of Arabidopsis plants following ANE application.
- Published
- 2021
14. A concise review of the brown macroalga Ascophyllum nodosum (Linnaeus) Le Jolis
- Author
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Alan T. Critchley, Liam Morrison, Pushp Sheel Shukla, and Leonel Pereira
- Subjects
0106 biological sciences ,Shore ,Biomass (ecology) ,geography ,Frond ,geography.geographical_feature_category ,Ecology ,010604 marine biology & hydrobiology ,Intertidal zone ,Plant Science ,Aquatic Science ,Biology ,biology.organism_classification ,01 natural sciences ,Nutrient ,Algae ,Climax community ,Ascophyllum ,010606 plant biology & botany - Abstract
Ascophyllum nodosum is a large and common brown alga. The fronds are olive-brown but can appear yellowish when stressed. It is a common, intertidal species around the periphery of the North Atlantic Ocean. It is particularly common on the north-western coast of Europe (from Svalbard to Portugal), including east Greenland, Iceland and the NE coast of N America (from New York to Newfoundland). This intertidal fucoid has long fronds with large egg-shaped airbladders. The fronds can reach 2 m (extremes of 5–7 m) in length. Depending on nutrient availability, the fronds are yellow, and at low tide, they can form extensive beds appearing to be monospecific to the casual observer. This seaweed is long lived and can be a dominant, climax community species of the middle shore. Ascophyllum nodosum is very effective at accumulating nutrients and minerals from the surrounding seawater. Due to the presence of many bioactive components, its harvested biomass is a valuable resource for human enterprise. This species is exploited for use in products such as food, fertiliser, soil conditioners, biostimulants (for phyco-elicitors), animal feed, skin and hair care products, cleaners, de-greasers, equestrian products and nutritional supplements. It is also a popular ingredient in cosmetology and thalassotherapy.
- Published
- 2020
15. Extracts of seaweeds used as biostimulants on land and sea crops—an efficacious, phyconomic, circular blue economy: with special reference to Ascophyllum (brown) and Kappaphycus (red) seaweeds
- Author
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Anicia Q. Hurtado, Iain C. Neish, Izabela Michalak, Jeffrey Norrie, Leonel Pereira, Pushp Sheel Shukla, Majid Khan Majahar Ali, and Alan T. Critchley
- Subjects
Brown algae ,Kappaphycus alvarezii ,Algae ,Sargassum ,Botany ,Ecklonia ,Biology ,biology.organism_classification ,Durvillaea ,Kappaphycus ,Ascophyllum - Abstract
Most of the world’s seaweed-derived extracts used for their biostimulatory/bioeffector properties for plants (i.e., abiotic and biotic stress reduction) are manufactured from brown algae, generally harvested from wild populations, or collected as storm-cast (e.g., Ascophyllum, Durvillaea, Ecklonia, Laminaria/Saccharina, Sargassum, etc.). Extracts of seaweeds have been applied for their phyconomic activities, including the micropropagation and cultivation of the red seaweed Kappaphycus alvarezii. These uses are increasingly important for the future success of sustainable, global, marine (blue) circular economies whereby applications of extracts have demonstrable biostimulatory/bioeffector properties for the benefits of mass cultivated, commercial seaweeds, thereby mirroring their use for land plants.
- Published
- 2021
16. Seaweed-Based Compounds and Products for Sustainable Protection against Plant Pathogens
- Author
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Pushp Sheel Shukla, Balakrishnan Prithiviraj, Alan T. Critchley, and Tudor Borza
- Subjects
0106 biological sciences ,Pharmaceutical Science ,Plant Immunity ,Review ,Biology ,plant pathogens ,01 natural sciences ,03 medical and health sciences ,Drug Discovery ,Sustainable agriculture ,Plant defense against herbivory ,Animals ,Humans ,Pharmacology, Toxicology and Pharmaceutics (miscellaneous) ,lcsh:QH301-705.5 ,030304 developmental biology ,Plant Diseases ,0303 health sciences ,Biological Products ,bioactive compounds ,business.industry ,fungi ,food and beverages ,Biotic stress ,Environmentally friendly ,Immunity, Innate ,Crop protection ,Biotechnology ,biostimulants ,lcsh:Biology (General) ,Agriculture ,seaweed ,business ,Systemic acquired resistance ,010606 plant biology & botany - Abstract
Sustainable agricultural practices increasingly demand novel, environmentally friendly compounds which induce plant immunity against pathogens. Stimulating plant immunity using seaweed extracts is a highly viable strategy, as these formulations contain many bio-elicitors (phyco-elicitors) which can significantly boost natural plant immunity. Certain bioactive elicitors present in a multitude of extracts of seaweeds (both commercially available and bench-scale laboratory formulations) activate pathogen-associated molecular patterns (PAMPs) due to their structural similarity (i.e., analogous structure) with pathogen-derived molecules. This is achieved via the priming and/or elicitation of the defense responses of the induced systemic resistance (ISR) and systemic acquired resistance (SAR) pathways. Knowledge accumulated over the past few decades is reviewed here, aiming to explain why certain seaweed-derived bioactives have such tremendous potential to elicit plant defense responses with considerable economic significance, particularly with increasing biotic stress impacts due to climate change and the concomitant move to sustainable agriculture and away from synthetic chemistry and environmental damage. Various extracts of seaweeds display remarkably different modes of action(s) which can manipulate the plant defense responses when applied. This review focuses on both the similarities and differences amongst the modes of actions of several different seaweed extracts, as well as their individual components. Novel biotechnological approaches for the development of new commercial products for crop protection, in a sustainable manner, are also suggested.
- Published
- 2020
17. Physiological and Transcriptomics Analyses Reveal that Ascophyllum nodosum Extracts Induce Salinity Tolerance in Arabidopsis by Regulating the Expression of Stress Responsive Genes
- Author
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Pushp Sheel Shukla, P. Kant, Balakrishnan Prithiviraj, M. N. Jithesh, Jyoti Joshi, and Alan T. Critchley
- Subjects
0106 biological sciences ,0301 basic medicine ,Abiotic stress ,Microarray analysis techniques ,Plant physiology ,Plant Science ,Biology ,Carbohydrate metabolism ,biology.organism_classification ,01 natural sciences ,Transcriptome ,03 medical and health sciences ,030104 developmental biology ,Biochemistry ,Arabidopsis ,Arabidopsis thaliana ,Agronomy and Crop Science ,Ascophyllum ,010606 plant biology & botany - Abstract
Extracts of the brown alga, Ascophyllum nodosum, are widely used as plant biostimulants to improve growth and to impart tolerance against abiotic stresses. However, the molecular mechanisms by which A. nodosum extract (ANE) mediates stress tolerance are still largely unknown. The aim of this study was to study selected anti-stress mechanisms at the transcriptome level. We show that methanolic sub-fractions of ANE improved growth of Arabidopsis thaliana under NaCl stress; biomass increased by approximately 50% under 100 mM and 150 mM NaCl, relative to the control. Bioassay-guided fractionation revealed that the ethyl acetate sub-fraction of ANE (EAA) had the majority of stress alleviating, bioactive components. Microarray analysis showed that EAA elicited substantial changes in the global transcriptome on day 1 and day 5, after treatment. On day one, 184 genes were up-regulated while this number increased to 257 genes on day 5. On the other hand, 91 and 262 genes were down-regulated on day 1 and day 5, respectively. On day 1, 2.2% of the genes altered were abiotic stress regulated and this increased to 6% on day 5. EAA modulate the expression of number of the genes involved in stress responses, carbohydrate metabolism, and phenylpropanoid metabolism. Thus, our results suggested that bioactive components in the ethyl acetate fraction of A. nodosum induced salinity tolerance in A. thaliana by modulating the expression of a plethora of stress-responsive genes, providing a better understanding of the mechanisms through which ANE mediates tolerance by plants to salinity stress.
- Published
- 2018
18. Ascophyllum nodosum-Based Biostimulants: Sustainable Applications in Agriculture for the Stimulation of Plant Growth, Stress Tolerance, and Disease Management
- Author
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Balakrishnan Prithiviraj, Mohd Adil, Emily Grace Mantin, Pushp Sheel Shukla, Alan T. Critchley, and Sruti Bajpai
- Subjects
0106 biological sciences ,Agrochemical ,Plant Science ,Review ,lcsh:Plant culture ,01 natural sciences ,03 medical and health sciences ,Nutrient ,Disease management (agriculture) ,lcsh:SB1-1110 ,Agricultural productivity ,Productivity ,030304 developmental biology ,2. Zero hunger ,Abiotic component ,0303 health sciences ,biology ,stress tolerance ,business.industry ,Ascophyllum nodosum ,fungi ,food and beverages ,plant growth ,15. Life on land ,biology.organism_classification ,Biotechnology ,biostimulants ,disease management ,Agriculture ,business ,Ascophyllum ,010606 plant biology & botany - Abstract
Abiotic and biotic stresses limit the growth and productivity of plants. In the current global scenario, in order to meet the requirements of the ever-increasing world population, chemical pesticides and synthetic fertilizers are used to boost agricultural production. These harmful chemicals pose a serious threat to the health of humans, animals, plants, and the entire biosphere. To minimize the agricultural chemical footprint, extracts of Ascophyllum nodosum (ANE) have been explored for their ability to improve plant growth and agricultural productivity. The scientific literature reviewed in this article attempts to explain how certain bioactive compounds present in extracts aid to improve plant tolerances to abiotic and/or biotic stresses, plant growth promotion, and their effects on root/microbe interactions. These reports have highlighted the use of various seaweed extracts in improving nutrient use efficiency in treated plants. These studies include investigations of physiological, biochemical, and molecular mechanisms as evidenced using model plants. However, the various modes of action of A. nodosum extracts have not been previously reviewed. The information presented in this review depicts the multiple, beneficial effects of A. nodosum-based biostimulant extracts on plant growth and their defense responses and suggests new opportunities for further applications for marked benefits in production and quality in the agriculture and horticultural sectors.
- Published
- 2019
19. First Report of Bacterial Leaf Blight of Strawberry Caused by Pantoea ananatis in Nova Scotia, Canada
- Author
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Sruti Bajpai, Kris Pruski, Mohd Adil, Samuel K. Asiedu, Balakrishnan Prithiviraj, and Pushp Sheel Shukla
- Subjects
Nova scotia ,Botany ,Blight ,Pantoea ananatis ,Plant Science ,Biology ,16S ribosomal RNA ,Pathogenicity ,Agronomy and Crop Science ,Ribosomal DNA - Published
- 2020
20. Ascophyllum nodosum extract mitigates salinity stress in Arabidopsis thaliana by modulating the expression of miRNA involved in stress tolerance and nutrient acquisition
- Author
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Balakrishnan Prithiviraj, Pushp Sheel Shukla, Tudor Borza, Jeff Norrie, David Hiltz, and Alan T. Critchley
- Subjects
0301 basic medicine ,Salinity ,Arabidopsis ,lcsh:Medicine ,Plant Science ,Biochemistry ,Physical Chemistry ,Plant Roots ,Salt Stress ,Gene Expression Regulation, Plant ,Plant Resistance to Abiotic Stress ,Gene expression ,Arabidopsis thaliana ,Gene Regulatory Networks ,lcsh:Science ,Ascophyllum ,Regulation of gene expression ,Plant Growth and Development ,Multidisciplinary ,biology ,Ecology ,Chemistry ,Plant Anatomy ,Eukaryota ,High-Throughput Nucleotide Sequencing ,Plants ,Cell biology ,Nucleic acids ,Root Growth ,Experimental Organism Systems ,RNA, Plant ,Plant Physiology ,Physical Sciences ,Research Article ,Arabidopsis Thaliana ,Brassica ,Research and Analysis Methods ,Phosphates ,03 medical and health sciences ,Model Organisms ,Plant and Algal Models ,Plant-Environment Interactions ,microRNA ,Genetics ,Plant Defenses ,Non-coding RNA ,Gene ,Natural antisense transcripts ,Biology and life sciences ,Arabidopsis Proteins ,Sequence Analysis, RNA ,Plant Ecology ,lcsh:R ,Ecology and Environmental Sciences ,Organisms ,Chemical Compounds ,RNA ,Plant Pathology ,biology.organism_classification ,Gene regulation ,Plant Leaves ,MicroRNAs ,030104 developmental biology ,Lateral Roots ,Chemical Properties ,Animal Studies ,lcsh:Q ,Developmental Biology - Abstract
Ascophyllum nodosum extract (ANE) contains bioactive compounds that improve the growth of Arabidopsis in experimentally-induced saline conditions; however, the molecular mechanisms through which ANE elicits tolerance to salinity remain largely unexplored. Micro RNAs (miRNAs) are key regulators of gene expression, playing crucial roles in plant growth, development, and stress tolerance. Next generation sequencing of miRNAs from leaves of control Arabidopsis and from plants subjected to three treatments (ANE, NaCl and ANE+NaCl) was used to identify ANE-responsive miRNA in the absence and presence of saline conditions. Differential gene expression analysis revealed that ANE had a strong effect on miRNAs expression in both conditions. In the presence of salinity, ANE tended to reduce the up-regulation or the down-regulation trend induced caused by NaCl in miRNAs such as ath-miR396a-5p, ath-miR399, ath-miR2111b and ath-miR827. To further uncover the effects of ANE, the expression of several target genes of a number of ANE-responsive miRNAs was analyzed by qPCR. NaCl, but not ANE, down-regulated miR396a-5p, which negatively regulated the expression of AtGRF7 leading to a higher expression of AtDREB2a and AtRD29 in the presence of ANE+NaCl, as compared to ANE alone. ANE+NaCl initially reduced and then enhanced the expression of ath-miR169g-5p, while the expression of the target genes AtNFYA1 and ATNFYA2, known to be involved in the salinity tolerance mechanism, was increased as compared to ANE or to NaCl treatments. ANE and ANE+NaCl modified the expression of ath-miR399, ath-miR827, ath-miR2111b, and their target genes AtUBC24, AtWAK2, AtSYG1 and At3g27150, suggesting a role of ANE in phosphate homeostasis. In vivo and in vitro experiments confirmed the improved growth of Arabidopsis in presence of ANE, in saline conditions and in phosphate-deprived medium, further substantiating the influence of ANE on a variety of essential physiological processes in Arabidopsis including salinity tolerance and phosphate uptake.
- Published
- 2018
21. Combination of Ascophyllum nodosum Extract and Humic Acid Improve Early Growth and Reduces Post-Harvest Loss of Lettuce and Spinach
- Author
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Svetlana N. Yurgel, Samuel K. Asiedu, Pushp Sheel Shukla, Monica Sandepogu, and Balakrishnan Prithiviraj
- Subjects
0106 biological sciences ,spinach ,Biomass ,Plant Science ,post-harvest loss ,01 natural sciences ,Lipid peroxidation ,chemistry.chemical_compound ,Humic acid ,lcsh:Agriculture (General) ,Ascophyllum nodosum extract ,chemistry.chemical_classification ,biology ,Sustainable strategy ,food and beverages ,plant growth ,04 agricultural and veterinary sciences ,biology.organism_classification ,lcsh:S1-972 ,lettuce ,biostimulants ,Antioxidant capacity ,Horticulture ,chemistry ,seaweed extract ,040103 agronomy & agriculture ,0401 agriculture, forestry, and fisheries ,Spinach ,Leafy vegetables ,Agronomy and Crop Science ,010606 plant biology & botany ,Food Science - Abstract
Leafy vegetables like lettuce and spinach are prone to significant post-harvest losses during handling and storage. The pre-harvest treatment of crops with biostimulants offers a sustainable strategy for reducing post-harvest losses. Earlier studies focused on the effect of plant biostimulants applied individually. In this study, we studied the efficacy of a combined application of two commonly used plant biostimulants: Ascophyllum nodosum extract (ANE) and humic acid (HA). Interestingly, the combination of both biostimulants improved early growth of lettuce and spinach compared to ANE and HA alone. Among the combinations used in this study, 0.25% ANE + 0.2% HA produced significantly higher fresh and dry biomass in lettuce and spinach compared to the other treatments and the control. Pre-harvest treatment of combination of 0.25% ANE and 0.2% HA significantly reduced the loss of fresh biomass during post-harvest storage. The combination of 0.25% ANE and 0.2% HA reduced lipid peroxidation during storage with an increase in total ascorbate, phenolic, and antioxidant capacity of spinach and lettuce. These results suggest that a combination of ANE and HA reduces post-harvest losses of spinach and lettuce more effectively than when applied individually.
- Published
- 2019
22. Overexpression of a novel SbMYB15 from Salicornia brachiata confers salinity and dehydration tolerance by reduced oxidative damage and improved photosynthesis in transgenic tobacco
- Author
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Parinita Agarwal, Pushp Sheel Shukla, Pradeep K. Agarwal, Bhavanath Jha, and Kapil Gupta
- Subjects
Salinity ,Stomatal conductance ,Gene Expression ,Salt-Tolerant Plants ,Hydrogen Peroxide ,Plant Science ,Biology ,Plants, Genetically Modified ,Malondialdehyde ,Oxidative Stress ,chemistry.chemical_compound ,chemistry ,Biochemistry ,Osmolyte ,Chlorophyll ,Halophyte ,Tobacco ,Genetics ,MYB ,Proline ,Transcription Factors - Abstract
SbMYB15, R2R3-type MYB was induced by the different stresses, and conferred stress tolerance in transgenic tobacco by regulating the expression of stress-responsive genes. MYBs are the master regulators of various metabolic processes and stress responses in plants. In this study, we functionally characterised a R2R3-type SbMYB15 transcription factor (TF) from the extreme halophyte Salicornia brachiata. The SbMYB15 acts as a transcriptional activator. Transcriptional analysis showed that SbMYB15 transcript was strongly upregulated in red shoots and was also induced by different stresses; however, its expression remained unchanged with ABA. Overexpression of SbMYB15 in tobacco significantly improved salinity and dehydration tolerance. The enhanced tolerance of the transgenic plants was defined by the changes in chlorophyll, malondialdehyde (MDA), proline, total soluble sugar and total amino acid contents. The transgenic plants exhibited a higher membrane stability and reduced electrolyte leakage, H2O2 and O 2 (-) content compared to the wild type (WT). With ionic stress, transgenics showed a low Na(+) and a high K(+) content. In the transgenic plants, the expression of stress-responsive genes such as LEA5, ERD10D, PLC3, LTP1, HSF2, ADC, P5CS, SOD and CAT was enhanced in the presence of salinity, dehydration and heat. Exposure to gradual salinity and dehydration resulted in an increased stomatal conductance, water use efficiency, photosynthesis rate, photochemical quenching and reduced transpiration rate. Thus, SbMYB15 served as an important mediator of stress responses regulating different stress signalling pathways, leading to enhanced stress tolerance.
- Published
- 2015
23. Seaweed extract improve drought tolerance of soybean by regulating stress-response genes
- Author
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Will Neily, Balakrishnan Prithiviraj, Alan T. Critchley, Pushp Sheel Shukla, Erin Norman, and Katy Shotton
- Subjects
0106 biological sciences ,0301 basic medicine ,Stomatal conductance ,plant biostimulant ,Antioxidant ,Short Communication ,medicine.medical_treatment ,Drought tolerance ,Plant Science ,commercial extract ,01 natural sciences ,03 medical and health sciences ,medicine ,soybean ,Water content ,biology ,Ascophyllum nodosum ,Agroforestry ,business.industry ,drought stress ,fungi ,food and beverages ,Plant physiology ,biology.organism_classification ,Horticulture ,030104 developmental biology ,Productivity (ecology) ,stomatal conductance ,Agriculture ,business ,Ascophyllum ,010606 plant biology & botany - Abstract
Ascophyllum nodosum extract (ANE) improved growth of soybean plants under drought stress. ANE treatment resulted in an increase in stomatal conductance and anti-oxidant activity in the leaf tissue. The application of ANE also modulated the expression of stress-responsive genes that ultimately resulted in improved growth under drought stress conditions. The results suggest ANE amplifies the plants' natural response to drought stress through change in the pattern of expression of stress response genes. This might be one plausible mode of action of ANE., There is an increasing global concern about the availability of water for agricultural use. Drought stress negatively impacts plant physiology and crop productivity. Soybean (Glycine max) is one of the important oilseed crops, and its productivity is often reduced by drought. In this study, a commercial extract of Ascophyllum nodosum (ANE) was evaluated for its potential to alleviate drought stress in soybean. The aim of this study was to determine the effects of ANE on the response of soybean plants to drought stress by monitoring stomatal conductance, relative leaf water content, antioxidant activity and expression of stress-responsive genes. Plants treated with ANE had higher relative water content and higher stomatal conductance under drought stress. During early recovery in the post-drought phase, ANE treated plants had significantly higher stomatal conductance. The antioxidant activity was also found higher in the plants treated with ANE. In addition, ANE-treatment led to changes in the expression of stress-responsive genes: GmCYP707A1a, GmCYP707A3b, GmRD22, GmRD20, GmDREB1B, GmERD1, GmNFYA3, FIB1a, GmPIP1b, GmGST, GmBIP and GmTp55. Taken together, these results suggest that applications of ANE improve the drought tolerance of soybean by changing physiology and gene expression.
- Published
- 2017
24. An enzymatic extract of the proliferative red seaweed Solieria chordalis reduces the virulence of Pseudomonas aeruginosa and stimulates the immune system of Caenorhabditis elegans
- Author
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Anne-Sophie Burlot, Garima Kulshreshtha, Sridhar Ravichandran, Pushp Sheel Shukla, Tudor Borza, Prithiviraj Balakrishnan, Gilles Bedoux, Nathalie Bourgougnon, Laboratoire de Biotechnologie et Chimie Marines (LBCM), Université de Brest (UBO)-Université de Bretagne Sud (UBS)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Burlot, Anne-Sophie, and Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM)
- Subjects
[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,[SDV.BV] Life Sciences [q-bio]/Vegetal Biology ,[SDV.BBM.BM]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,[SDV.MP.BAC] Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,[SDV.BBM.BM] Life Sciences [q-bio]/Biochemistry, Molecular Biology/Molecular biology ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,ComputingMilieux_MISCELLANEOUS ,[SDV.BIO] Life Sciences [q-bio]/Biotechnology - Abstract
International audience
- Published
- 2017
25. Microbial Degradation of Lobster Shells to Extract Chitin Derivatives for Plant Disease Management
- Author
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Gayathri Ilangumaran, Pushp Sheel Shukla, Samuel K. Asiedu, G. W. Stratton, Philippe Potin, Balakrishnan Prithiviraj, Sridhar Ravichandran, Dalhousie University [Halifax], Station biologique de Roscoff [Roscoff] (SBR), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
0106 biological sciences ,0301 basic medicine ,Microbiology (medical) ,[SDV.BIO]Life Sciences [q-bio]/Biotechnology ,Bioconversion ,Microorganism ,lcsh:QR1-502 ,01 natural sciences ,Microbiology ,biodegradation ,lcsh:Microbiology ,03 medical and health sciences ,chemistry.chemical_compound ,Chitin ,lobster shells ,plant defense ,Food science ,Shellfish ,Original Research ,Botrytis cinerea ,biology ,fungi ,Biodegradation ,biology.organism_classification ,Plant disease ,Streptomyces ,[SDV.BV.PEP]Life Sciences [q-bio]/Vegetal Biology/Phytopathology and phytopharmacy ,030104 developmental biology ,chemistry ,chitinase ,Chitinase ,biology.protein ,010606 plant biology & botany - Abstract
International audience; Biodegradation of lobster shells by chitinolytic microorganisms are an environment safe approach to utilize lobster processing wastes for chitin derivation. In this study, we report degradation activities of two microbes, " S223 " and " S224 " isolated from soil samples that had the highest rate of deproteinization, demineralization and chitinolysis among ten microorganisms screened. Isolates S223 and S224 had 27.3 and 103.8 protease units mg −1 protein and 12.3 and 11.2 µg ml −1 of calcium in their samples, respectively, after 1 week of incubation with raw lobster shells. Further, S223 contained 23.8 µg ml −1 of N-Acetylglucosamine on day 3, while S224 had 27.3 µg ml −1 on day 7 of incubation with chitin. Morphological observations and 16S rDNA sequencing suggested both the isolates were Streptomyces. The culture conditions were optimized for efficient degradation of lobster shells and chitinase (∼30 kDa) was purified from crude extract by affinity chromatography. The digested lobster shell extracts induced disease resistance in Arabidopsis by induction of defense related genes (PR1 > 500-fold, PDF1.2 > 40-fold) upon Pseudomonas syringae and Botrytis cinerea infection. The study suggests that soil microbes aid in sustainable bioconversion of lobster shells and extraction of chitin derivatives that could be applied in plant protection.
- Published
- 2017
26. High-frequency in vitro shoot regeneration in Cucumis sativus by inhibition of endogenous auxin
- Author
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Pushp Sheel Shukla, Bhavanath Jha, Pradeep K. Agarwal, and Arun Kumar Das
- Subjects
chemistry.chemical_classification ,food.ingredient ,fungi ,food and beverages ,Plant Science ,Biology ,biology.organism_classification ,Plantlet ,food ,chemistry ,Auxin ,Shoot ,Botany ,Cultivar ,Cucumis ,Developmental biology ,Cotyledon ,Biotechnology ,Explant culture - Abstract
Direct in vitro plantlet regeneration was studied in cucumber (Cucumis sativus), an important vegetable crop. The endogenous auxin concentration was quantified by HPLC in young cotyledon explants, and we observed that higher auxin content promotes callusing and inhibits direct shoot regeneration. Lowering the endogenous auxin concentration by the application of the auxin inhibitor 2,3,5-triiodobenzoic acid (TIBA), as confirmed by HPLC, increased the frequency of shoot regeneration. The auxin content was reduced by increasing the concentration of TIBA in cvs. Pant Kheera 1 and Pusa Uday. Regeneration efficiencies were dependent on explant age and cultivar. The 2-d-old explants gave the highest regeneration efficiencies, with Pusa Uday showing higher regeneration potential than PK-1. Shoot buds/small shoots transferred to Murashige and Skoog (MS) medium supplemented with 1 μM 6-benzylaminopurine grew vigorously and attained 1- to 2-cm length in 4 wk. These shoots rooted with 100% efficiency on MS basal medium or MS basal medium supplemented with 0.5 μM indole-3-acetic acid. The hardened plants showed normal growth and flowering under greenhouse conditions.
- Published
- 2014
27. Bioengineering for Salinity Tolerance in Plants: State of the Art
- Author
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Pushp Sheel Shukla, Pradeep K. Agarwal, Kapil Gupta, and Bhavanath Jha
- Subjects
Salinity ,Bioengineering ,Computational biology ,Biology ,Applied Microbiology and Biotechnology ,Biochemistry ,Gene Expression Regulation, Plant ,Stress, Physiological ,Molecular Biology ,Gene ,Transcription factor ,Plant Physiological Phenomena ,Regulator gene ,Regulation of gene expression ,business.industry ,Abiotic stress ,Salt Tolerance ,Plants ,Plants, Genetically Modified ,Adaptation, Physiological ,Biotechnology ,Ion homeostasis ,Adaptation ,Genetic Engineering ,business ,Function (biology) - Abstract
Genetic engineering of plants for abiotic stress tolerance is a challenging task because of its multifarious nature. Comprehensive studies for developing abiotic stress tolerance are in progress, involving genes from different pathways including osmolyte synthesis, ion homeostasis, antioxidative pathways, and regulatory genes. In the last decade, several attempts have been made to substantiate the role of "single-function" gene(s) as well as transcription factor(s) for abiotic stress tolerance. Since, the abiotic stress tolerance is multigenic in nature, therefore, the recent trend is shifting towards genetic transformation of multiple genes or transcription factors. A large number of crop plants are being engineered by abiotic stress tolerant genes and have shown the stress tolerance mostly at laboratory level. This review presents a mechanistic view of different pathways and emphasizes the function of different genes in conferring salt tolerance by genetic engineering approach. It also highlights the details of successes achieved in developing salt tolerance in plants thus far.
- Published
- 2012
28. Improved Salinity Tolerance of Arachis hypogaea (L.) by the Interaction of Halotolerant Plant-Growth-Promoting Rhizobacteria
- Author
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Bhavanath Jha, Pradeep K. Agarwal, and Pushp Sheel Shukla
- Subjects
biology ,Hypogaea ,fungi ,food and beverages ,Plant physiology ,Plant Science ,Rhizobacteria ,biology.organism_classification ,Arachis hypogaea ,Salinity ,Dry weight ,Agronomy ,Shoot ,Halotolerance ,Agronomy and Crop Science - Abstract
Salinity adversely affects plant growth and development. Halotolerant plant-growth-promoting rhizobacteria (PGPR) alleviate salt stress and help plants to maintain better growth. In the present study, six PGPR strains were analyzed for their involvement in salt-stress tolerance in Arachis hypogaea. Different growth parameters, electrolyte leakage, water content, biochemical properties, and ion content were analyzed in the PGPR-inoculated plants under 100 mM NaCl. Three bacterial strains, namely, Brachybacteriumsaurashtrense (JG-06), Brevibacteriumcasei (JG-08), and Haererohalobacter (JG-11), showed the best growth of A. hypogaea seedlings under salt stress. Plant length, shoot length, root length, shoot dry weight, root dry weight, and total biomass were significantly higher in inoculated plants compared to uninoculated plants. The PGPR-inoculated plants were quite healthy and hydrated, whereas the uninoculated plant leaves were desiccated in the presence of 100 mM NaCl. The percentage water content (PWC) in the shoots and roots was also significantly higher in inoculated plants compared to uninoculated plants. Proline content and soluble sugars were significantly low, whereas amino acids were higher than in uninoculated plants. The MDA content was higher in uninoculated plants than in inoculated plants at 100 mM NaCl. The inoculated plants also had a higher K+/Na+ ratio and higher Ca2+, phosphorus, and nitrogen content. The auxin concentration was higher in both shoot and root explants in the inoculated plants. Therefore, it could be predicted that all these parameters cumulatively improve plant growth under saline conditions in the presence of PGPR. This study shows that PGPR play an important role in inducing salinity tolerance in plants and can be used to grow salt-sensitive crops in saline areas.
- Published
- 2011
29. The SbSOS1 gene from the extreme halophyte Salicornia brachiata enhances Na+ loading in xylem and confers salt tolerance in transgenic tobacco
- Author
-
Bhavanath Jha, Pushp Sheel Shukla, Narendra Singh Yadav, Anupama Jha, and Pradeep K. Agarwal
- Subjects
Sodium-Hydrogen Exchangers ,Antiporter ,Na+ loading ,Plant Science ,Chenopodiaceae ,Sodium Chloride ,Biology ,Genes, Plant ,chemistry.chemical_compound ,Transformation, Genetic ,Gene Expression Regulation, Plant ,Xylem ,Halophyte ,lcsh:Botany ,Tobacco ,Botany ,SbSOS1 ,Proline ,Cloning, Molecular ,fungi ,Transgenic plants ,food and beverages ,Salt-Tolerant Plants ,Plants, Genetically Modified ,Salinity tolerance ,Salicornia brachiata ,lcsh:QK1-989 ,Salinity ,Ion homeostasis ,Biochemistry ,chemistry ,Chlorophyll ,Shoot ,Research Article - Abstract
Background Soil salinity adversely affects plant growth and development and disturbs intracellular ion homeostasis resulting cellular toxicity. The Salt Overly Sensitive 1 (SOS1) gene encodes a plasma membrane Na+/H+ antiporter that plays an important role in imparting salt stress tolerance to plants. Here, we report the cloning and characterisation of the SbSOS1 gene from Salicornia brachiata, an extreme halophyte. Results The SbSOS1 gene is 3774 bp long and encodes a protein of 1159 amino acids. SbSOS1 exhibited a greater level of constitutive expression in roots than in shoots and was further increased by salt stress. Overexpressing the S. brachiata SbSOS1 gene in tobacco conferred high salt tolerance, promoted seed germination and increased root length, shoot length, leaf area, fresh weight, dry weight, relative water content (RWC), chlorophyll, K+/Na+ ratio, membrane stability index, soluble sugar, proline and amino acid content relative to wild type (WT) plants. Transgenic plants exhibited reductions in electrolyte leakage, reactive oxygen species (ROS) and MDA content in response to salt stress, which probably occurred because of reduced cytosolic Na+ content and oxidative damage. At higher salt stress, transgenic tobacco plants exhibited reduced Na+ content in root and leaf and higher concentrations in stem and xylem sap relative to WT, which suggests a role of SbSOS1 in Na+ loading to xylem from root and leaf tissues. Transgenic lines also showed increased K+ and Ca2+ content in root tissue compared to WT, which reflect that SbSOS1 indirectly affects the other transporters activity. Conclusions Overexpression of SbSOS1 in tobacco conferred a high degree of salt tolerance, enhanced plant growth and altered physiological and biochemical parameters in response to salt stress. In addition to Na+ efflux outside the plasma membrane, SbSOS1 also helps to maintain variable Na+ content in different organs and also affect the other transporters activity indirectly. These results broaden the role of SbSOS1 in planta and suggest that this gene could be used to develop salt-tolerant transgenic crops.
- Published
- 2012
30. Molecular characterization of an MYB transcription factor from a succulent halophyte involved in stress tolerance
- Author
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Parinita Agarwal, Kapil Gupta, Pushp Sheel Shukla, and Pradeep K. Agarwal
- Subjects
Abiotic component ,Abiotic stress ,fungi ,food and beverages ,R2R3-MYB ,Plant Science ,yeast ,Biology ,Cell biology ,chemistry.chemical_compound ,chemistry ,halophyte ,Halophyte ,Salicornia brachiata ,Botany ,MYB ,Abscisic acid ,Gene ,Transcription factor ,Research Articles ,transcription factor ,Regulator gene - Abstract
Abiotic stresses cause dramatic changes in agricultural productivity. Plants encounter a wide range of biotic stresses and have evolved mechanisms to increase tolerance through both physical adaptations and interactive molecular and cellular changes that begin after the onset of stress. Transcription factors regulate the gene expression associated with both abiotic and biotic stresses, growth, metabolism, and plant development. SbMYB44 is an R2R3 type transcription factor involved in stress regulation in an extreme halophyte, Salicornia brachiata. SbMYB44 binds to the cis elements of a stress responsive promoter and confers stress tolerance. In future, SbMYb44 may prove to be a candidate gene for developing stress tolerance in crop plants., Abiotic stresses like drought, salinity and extreme temperature significantly affect crop productivity. Plants respond at molecular, cellular and physiological levels for management of stress tolerance. Functional and regulatory genes play a major role in controlling these abiotic stresses through an intricate network of transcriptional machinery. Transcription factors are potential tools for manipulating stress tolerance since they control a large number of downstream genes. In the present study, we have isolated SbMYB44 from a succulent halophyte, Salicornia brachiata Roxb. SbMYB44 with an open-reading frame of 810 bp encodes a protein of 269 amino acids, with an estimated molecular mass of 30.31 kDa and an isoelectric point of 6.29. The in silico analysis revealed that the SbMYB44 protein contains the conserved R2R3 imperfect repeats, two SANT domains and post-translational modification sites. The SbMYB44 transcript showed up-regulation in response to salinity, desiccation, high temperature, and abscisic acid and salicylic acid treatments. The SbMYB44 recombinant protein showed binding to dehydration-responsive cis-elements (RD22 and MBS-1), suggesting its possible role in stress signalling. Overexpression of SbMYB44 enhanced the growth of yeast cells under both ionic and osmotic stresses.
- Published
- 2015
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