
Balakrishnan PrithivirajDalhousie University | Dal · Department of Plant, Food and Environmental Sciences
Balakrishnan Prithiviraj
Ph.D.
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229
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Introduction
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September 2005 - present
Publications
Publications (229)
Flowering, the change from vegetative development to the reproductive phase, represents a crucial and intricate stage in the life cycle of plants, which is tightly controlled by both internal and external factors. In this study, we investigated the effect of Ascophyllum nodosum extract (ANE) on the flowering time of Arabidopsis. We found that a 0.1...
Soil health is important for crop production and plays a vital role in ensuring global food security. Microbial and nonmicrobial plant biostimulants have been found to improve soil quality by promoting soil physicochemical properties, structure, and microbial diversity. These benefits can help mitigate the effects of climate change, as healthier so...
Potato and tomato are grown in all Canadian provinces and contribute billions of dollars in exports and sales. Late blight, caused by Phytophthora infestans, is a destructive disease of potato and tomato worldwide and is responsible for millions of dollars in losses annually. Changes in pathogen strains were reported to be associated with late blig...
Phytophthora infestans is the most economically important pathogen of potato and tomato worldwide. Preventative fungicide spraying remains the most effective management option for controlling late blight caused by P. infestans. Worldwide, plant protection products against late blight are costing producers several billions of dollars annually. Incre...
Late blight caused by Phytophthora infestans is an economically important disease of potato and tomato worldwide. In Canada, increases in late blight incidence and severity coincided with changes in the genetic composition of P. infestans. We monitored late blight incidence on tomato and potato crops in Pacific western and eastern Canada between 20...
Late blight caused by Phytophthora infestans is an economically important disease of potato and tomato worldwide. In Canada, an increase in late blight incidence and severity coincided with changes in genetic composition of P. infestans. We monitored late blight incidence on tomato and potato in Pacific western and eastern Canada between 2019 and 2...
Saxitoxin (STX) causes high toxicity by blocking voltage-gated sodium channels, and it poses a major threat to marine ecosystems and human health worldwide. Our work evaluated the neurotoxicity and chronic toxicology of STX to Caenorhabditis elegans by an analysis of lifespan, brood size, growth ability, reactive oxygen species (ROS) and adenosine...
Plant diseases cause significant damage to global agriculture, leading to crop loss and reduced crop quality and nutritional value. Traditional methods of controlling plant diseases, such as synthetic pesticides and fungicides, have negative impacts on human health and the environment. As a result, there has been increasing interest in finding more...
Abiotic stresses, including salinity stress, affect numerous crops, causing yield reduction, and, as a result, important economic losses. Extracts from the brown alga Ascophyllum nodosum (ANE), and compounds secreted by the Pseudomonas protegens strain, CHA0, can mitigate these effects by inducing tolerance against salt stress. However, the influen...
The maintenance of the beneficial plant microbiome to control plant pathogens is an emerging concept of disease management, and necessitates a clear understanding of these microbial communities and the environmental factors that affect their diversity and compositional structure. As such, studies investigating the microbiome of economically signifi...
The brown alga Ectocarpus sp. belongs to Phaeophyceae, a class of macroalgae in the phylum Heterokonts, which is also
known as the Stramenopiles lineage. Ectocarpus is a dominant seaweed in temperate regions around the globe, abundant
mostly in the intertidal zone, a habitat with harsh environmental conditions resulting from tidal cycles. Analysis...
Clonostachys rosea, an ascomycetous, omnipresent, cellulose-decaying soil fungus, has been reported to be a well-known mycoparasitic biological control agent. In this study, we isolated C. rosea, a mycoparasitic fungus for the first time in India from sclerotia of the notorious plant pathogen Sclerotinia sclerotiorum, causing head rot disease in ca...
Background
Antibiotic-resistant Gram-negative bacteria are becoming a major public health threat such as the important opportunistic pathogen Pseudomonas aeruginosa ( P. aeruginosa ). The present study investigated enhancement of the linezolid spectrum, which is normally used to treat Gram-positive bacteria, at inhibiting P. aeruginosa growth.
Met...
Bacterial species in the polymicrobial community evolve interspecific interaction relationships to adapt to the survival stresses imposed by neighbors or environmental cues. Pseudomonas aeruginosa and Staphylococcus aureus are two common bacterial pathogens frequently coisolated from patients with burns and respiratory disease. Whether the applicat...
Background
Trueperella pyogenes and Pseudomonas aeruginosa are two important bacterial pathogens closely relating to the occurrence and development of forest musk deer respiratory purulent disease. Although T. pyogenes is the causative agent of the disease, the subsequently invaded P. aeruginosa will predominate the infection by producing a substan...
A R T I C L E I N F O Keywords: Alzheimer's disease Drosophila melanogaster Flavonoid-rich ascophyllum nodosum Mitochondrial Oxidative stress A B S T R A C T Background: In Alzheimer Disease (AD) pathogenesis, aggregation of Aβ 42 fibrils strongly correlates with memory dysfunction and neurotoxicity. Till date, no promising cures for AD. Report sho...
Background: In Alzheimer Disease (AD) pathogenesis, aggregation of Aβ42 fibrils strongly correlates with memory dysfunction and neurotoxicity. Till date, no promising cures for AD. Report shows that flavonoids contributed anti-oxidant, anti-cancer and neuroprotection activity by regulating the mitochondrial machinery. Here, we first report the iden...
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...
Background: Trueperella pyogenes and Pseudomonas aeruginosa are two important bacterial pathogens closely relating to the occurrence and development of forest musk deer respiratory purulent disease. Although T. pyogenes is the causative agent of the disease, the subsequently invaded P. aeruginosa will predominate the infection by producing a substa...
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...
Ascophyllum nodosum extracts (ANE) are well-established plant biostimulants that improve stress tolerance and crop vigour, while also having been shown to stimulate soil microbes. The intersection of these two stimulatory activities, and how they combine to enhance plant health, however, remains poorly understood. In the present study, we aimed to...
Interspecific interaction happens frequently among bacterial species and can promote the colonization of polymicrobial community in various environments. However, it is not clear whether the intervention of antibiotics, which is a common therapeutic method for infectious disease, will influence the interacting dynamics of different pathogenic bacte...
PsiPred predictions of the secondary structure. (a) PsiPred sequence plot and (b) PsiPred cartoon with confidence of prediction. Models were generated at: http://bioinf.cs.ucl.ac.uk/psipred/
Esi0017_0056 tertiary structure modelling. (a) Tertiary structure of the DUF1768-domain built with ProMod3 3.0.0 in SWISS-MODEL using as template the hypothetical protein ybiA (SMTL ID: 2b3w.1.A); (b). The region covering residues 132 – 291 which was used to build the model, based on similarity with ybiA and (c). Tertiary structure of the full-leng...
Growth of wild type and 2 independent 35S promoter (Es17Ox-1-2,) and of 3 independent stress inducible promoter (Es17A-C) transgenic A. thaliana plants, expressing Esi0017_0056, in standard conditions. (a) WT, (b) Es17-A, (c) Es17-B, (d) Es17-C, (e) Es17-Ox1, (f) Es17-Ox2. The plants were photographed at 20 days after irrigation.
Growth of wild type and 2 independent 35S promoter (Es17Ox-1-2,) and of 3 independent stress inducible promoter (Es17A-C) transgenic A. thaliana seedlings under high temperature stress and standard conditions. The seedlings in plates (a) to (f), were exposed to high temperature stress while seedlings in plates (g) to (l), were grown in standard con...
Gene structure of Esi0017_0056 indicating the presence of two introns.
Different constructs generated for expression of Esi0017_0056 in plants and bacteria. (a) Expression under N-terminal 6xHis tag fusion. (b) C-terminal GUS fusion. (c) C-terminal GFP fusion. (d) Expression under 35S promoter in A. thaliana. (e) Expression under RD29A promoter in A. thaliana.
The output from different prediction software/severs on potential intracellular localization of Esi0017_0056.
Phylogenetic analysis of Esi0017_0056 protein using the Maximum Likelihood method and JTT matrix-based model. The percentage of trees in which the associated taxa clustered together is shown next to the branches.
Expression of Esi0017_0056 protein with N-6xHis tag in E. coli BL21 DE3 cells. Lane 1, uninduced whole cells; lane 2, induced whole cells; lanes 3 to 5, supernatant of cell lysate; and lanes 6 to 8 pellet of cell lysate.
Gene expression analysis of stress inducible marker genes in the wild type and transgenic A. thaliana plants (Es17Ox-1) grown in absence and presence of 100 mM NaCl. Two time points (24 and 120 h) were studied. Actin was used as the endogenous control and transcript levels were normalized to the individual with the lowest expression. Default font v...
Brown alga Ectocarpus sp. belongs to Phaeophyceae, a class of macroalgae that evolved complex multicellularity. Ectocarpus sp. is a dominant seaweed in temperate regions, abundant mostly in the intertidal zones, an environment with high levels of abiotic stresses. Previous transcriptomic analysis of Ectocarpus sp. revealed several genes consistentl...
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. Certai...
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...
The Gram-negative pathogen Pseudomonas aeruginosa adopts several elaborate strategies to colonize a wide range of natural or clinical niches and to overcome the neighboring bacterial competitors in polymicrobial communities. However, the relationship and interaction mechanism of P. aeruginosa with other bacterial pathogens remains largely unexplore...
Mannitol is abundant in a wide range of organisms, playing important roles in biotic and abiotic stress responses. Nonetheless, mannitol is not produced by a vast majority of plants, including many important crop plants. Mannitol-producing transgenic plants displayed improved tolerance to salt stresses though mannitol production was rather low, in...
Seaweeds comprise ca. 12,000 species. Global annual harvest is ca. 30.13 million metric tonnes, (valued ca. $11.7 billion USD in 2016) for various commercial applications. The growing scope of seaweed-based applications in food, agricultural fertilizers, animal feed additives, pharmaceuticals, cosmetics and personal care is expected to boost market...
Strawberry cropping system relies heavily on proper disease management to maintain high crop yield. Powdery mildew, caused by Sphaerotheca macularis (Wall. Ex Fries) is one of the major leaf diseases in strawberry which can cause significant yield losses up to 70%. Field scouts manually walk beside strawberry fields and visually observe the plants...
Poultry and its products are an economical source of high-quality protein for human consumption. In animal agriculture, antibiotics are used as therapeutic agents to treat disease in livestock, or as prophylactics to prevent disease and in so doing enhance production. However, the extensive use of antibiotics in livestock husbandry has come at the...
Botrytis blossom blight is an important disease of wild blueberries in Canada that causes over 20% yield losses annually. Four trials (2 in each year) were set up in 2015 and 2016 to investigate the efficacy of biofungicides against Botrytis blossom blight in wild blueberry. Botector®, Fracture® and Serenade MAX® were evaluated alone and in rotatio...
Background:
Powdery mildew (PM) is an important disease of pea that reduce yield. Ascophyllum nodosum extract (ANE) and chitosan (CHT) are biostimulants used to improve plant health. Efficacy of ANE and CHT was assessed individually and in combination against pea powdery mildew.
Results:
Combined applications of ANE and CHT had a significant inh...
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 eff...
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 bios-timulant 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, appli...
Fusarium head blight (FHB) caused by Fusarium graminearum is a disease that results in yield loss and mycotoxin contamination in wheat globally. This study assessed the effect of a plant biostimulant prepared from a brown macroalga Ascophyllum nodosum (Liquid Seaweed Extract; LSE) alone and in combination with chitosan in controlling Fusarium. Whea...
Strawberry is an important fruit crop in Canada but powdery mildew (PM) results in about 30–70% yield loss. Detection of PM through an image texture-based system is beneficial, as it identifies the symptoms at an earlier stage and reduces labour intensive manual monitoring of crop fields. This paper presents an image texture-based disease detection...
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...
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, p...
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, p...
The study of bioactive components of the brown alga Ascophyllum nodosum (L.) Le Jolis has shown that they promote growth and increase productivity of plants. However, a standardized model system providing consistent responses to such bioactive components has yet to be established. Given that freezing stress, especially in northern climates, reduces...
Strawberry plants have been facing a significant proportion of diseases during cultivation, scattered throughout the field, emphasizing the need for proper diseases management. Powdery mildew is one of the major fungal strawberry disease which is typically responsible for approximately 30-70% loss of yields. The aim of this study was to develop a m...
Seaweeds have been used for centuries as organic inputs to improve soil properties and more recently extracts of seaweeds have been used as biostimulants to enhance the growth of agricultural crops. However, their potential as biocontrol agents, as used to suppress plant diseases, has not been broadly exploited, due to the lack of cohesive scientif...
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 grow...
MA plot of distribution of differentially expressed genes in Arabidopsis between the various treatments at 12 h.
C: Control, T1: ANE, T2: ANE+NaCl, T3: NaCl.
(TIF)
List of target genes predicted.
(DOCX)
(a) Average number of reads (in millions) obtained from sequencing the libraries from control and the 3 treatments (ANE, ANE+NaCl and NaCl) after 6 and 12 h of treatment. (b) Average number of miRNA mapped to the Arabidopsis genome in the libraries from control and the three treatments. Error bars represent SE.
(TIF)
Size distribution of miRNA sequences in the libraries from control and the three treatments (ANE, ANE+NaCl and NaCl), constructed from the leaves of Arabidopsis after 6 h (a) and 12 h (b) of treatment.
(TIF)
MA plot of distribution of differentially expressed genes in Arabidopsis between the various treatments at 6 h.
C: Control, T1: ANE, T2: ANE+NaCl, T3: NaCl.
(TIF)
List of the primers used in target gene expression analysis.
(DOCX)
Three-week-old Arabidopsis plants before being supplemented with water (a), 100 mM NaCl (b), 0.1% ANE (c), and 0.1% ANE with 100 mM NaCl (d).
(TIF)
ANE improves growth of Arabidopsis in the presence of salinity.
The effects of ANE in absence and presence of salinity stress on the in vitro growth of 7 days old Arabidopsis seedlings grown in ½ MS media (a) or supplemented with 100 mM NaCl (b), 0.1% ANE (c), and 0.1% ANE with 100 mM NaCl (d). The effect of ANE on the fresh (e) and dry weight (f)...
ANE modulates root system architecture of Arabidopsis in the presence of salinity.
The effects of ANE in absence and presence of salinity stress on root system architecture of Arabidopsis seedlings grown on in vitro conditions. (a) The effect of ANE on the primary root length, (b) average length and (c) the number of lateral roots of Arabidopsis se...
The effects of ANE in absence and presence of salinity stress and of phosphate on the in vitro improves the growth of 7 days old Arabidopsis seedlings supplemented with 0 mM NaCl (a), 0.01% ANE (b), 100 mM NaCl (c), and 0.01% ANE with 100 mM NaCl (d) and phosphate starved media with 0 mM NaCl (e), 0.01% ANE (f), 100 mM NaCl (g), and 0.01% ANE with...
Na+, K+, K+/Na+ ratio and P content of the Arabidopsis grown in the presence of control, ANE (T1), ANE+NaCl (T2) and NaCl (T3).
(DOCX)
The effects of ANE in absence and presence of salinity stress and of phosphate on the root system architecture of Arabidopsis seedlings in the presence of controls and phosphate-depleted medium ANE, ANE + 100 mM NaCl and 100 mM NaCl.
The effect of ANE on the primary root length (a), average length (b), and number (c) of lateral roots of Arabidopsis...
Differential expression of conserved Arabidopsis miRNAs among control (C), ANE (T1) and ANE+NaCl (T2) and NaCl (T3) treatments at 6 h.
(DOCX)
The differential expression of conserved Arabidopsis miRNAs among control (C), ANE (T1) and ANE+NaCl (T2) and NaCl (T3) treatments at 12 h.
(DOCX)
Plant and environmental factors affect root nitrogen (N) exudation dynamics in legumes. To better understand the genotypic variability and plant factors affecting root N release nodulation, plant growth, tissue N content, and root N exudation, six (three diploid and three tetraploid) red clover (Trifolium pratense L.) varieties were evaluated under...