Extracellular polymeric substances in psychrophilic cyanobacteria: A potential bioflocculant and carbon sink to mitigate cold stress

Shafeeq, Tahir; Hamid, Basharat; Baba, Zahoor Ahmad; Iqbal, Sajid; Yatoo, Ali Mohd; Fatima, Sabah; Nabi, Asha; Kanth, Rehana; Dar, Khursheed; Hussain, Nazir; Alturki, Ahmad-I; Kumari, Sunita; Sayyed, R. Z.

doi:10.1016/j.bcab.2022.102375

Cited by 20 publications

(13 citation statements)

References 98 publications

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“…These signal molecules freely diffuse to the cells and bind to their respective receptors, thus regulating various pathogenesis-related traits. The production of EPS (Ilyas et al, 2020 ; Sheikh et al, 2022 ), pigment (Polapally et al, 2022 ), toxins, formation of biofilm (Ali et al, 2022 ; Fazeli-Nasab et al, 2022 ), and secretion of cell wall degrading enzymes (Jadhav et al, 2020 ) are key traits expressed by the pathogen once sufficient cell density is achieved (Sibanda et al, 2018 ). This quorum-sensing guided virulence factor synthesis can be controlled by disturbing the QS system either by mimicking the signal molecules, which leads to competitive inhibition, or enzymatically hydrolyse the auto-inducers (N-Homoserine Lactone).…”

Section: Discussionmentioning

confidence: 99%

Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation

et al. 2022

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The quorum-sensing (QS) cascade is responsible for the colonization and phenotypic behavior of the pathogenic organism and the regulation of diverse signal molecules. The disruption of the quorum-sensing system is an effective strategy to overcome the possibility of antibiotic resistance development in the pathogen. The quorum quenching does not kill the microbes. Instead, it hinders the expression of pathogenic traits. In the present experiment, Pseudomonas aeruginosa RKC1 was used to extract the metabolites responsible for quorum-sensing inhibition in soft rot pathogen Lelliottia amnigena RCE. During the initial screening, P. aeruginosa RKC1 was found to be most promising and inhibits violacein of Chromobacterium violaceum MTCC2656 pyocyanin, swarming-swimming motility of P. aeruginosa MTCC2297. The characterization of metabolites produced by the microbes which are responsible for quorum-sensing inhibition through GC-MS is very scarce in scientific literature. The ethyl acetate extract of P. aeruginosa RKC1 inhibits biofilm formation of L. amnigena RCE while inhibiting growth at higher concentrations. The GC-MS analysis suggested that Cyclic dipeptides (CDPs) such as Cyclo (L-prolyl-L-valine), Cyclo (Pro-Leu), and Cyclo(D-phenylalanyl-L-prolyl) were predominantly found in the ethyl acetate extract of the P. aeruginosa RKC1 (93.72%). This diketopiperazine (DKPs) exhibited quorum-sensing inhibition against the pathogen in liquid media during the active growth phase and regulated diverse metabolites of the pathogen. Moreover, the metabolites data from the clear zone around wells showed a higher concentration of DKSs (9.66%) compared to other metabolites. So far, very few reports indicate the role of DKPs or CDPs in inhibiting the quorum-sensing system in plant pathogenic bacteria. This is one such report that exploits metabolites of P. aeruginosa RKC1. The present investigation provided evidence to use quorum-sensing inhibitor metabolites, to suppress microbes' pathogenesis and thus develop an innovative strategy to overcome antibiotic resistance.

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Section: Discussionmentioning

confidence: 99%

Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation

et al. 2022

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“…The most important mechanisms to maintain osmotic balance are osmoregulation and osmoprotection. Osmoregulation is the process of maintaining cell turgor by lowering osmotic potential (Ψ) via synthesis and accumulation of osmoprotectants (or osmolytes), such as soluble proteins, amino acids, quaternary ammonium compounds, polyamines, sugars, and sugar alcohols in plants [ 121 , 122 ]. Osmoprotection either boosts the antioxidant defense system or assists with ion homeostasis.…”

Section: Plant Growth Promoting Rhizobacteria Mediated Drought Stress...mentioning

confidence: 99%

Insight into Recent Progress and Perspectives in Improvement of Antioxidant Machinery upon PGPR Augmentation in Plants under Drought Stress: A Review

Gowtham¹,

Singh

Shilpa

et al. 2022

Antioxidants

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Agriculture has a lot of responsibility as the rise in the world’s population demands more food requirements. However, more than one type of biotic and abiotic stress continually impacts agricultural productivity. Drought stress is a major abiotic stress that significantly affects agricultural productivity every year as the plants undergo several morphological, biochemical, and physiological modifications, such as repressed root and shoot growth, reduced photosynthesis and transpiration rate, excessive production of reactive oxygen species (ROS), osmotic adjustments, and modified leaf senescence regulating and stress signaling pathways. Such modifications may permanently damage the plants; therefore, mitigation strategies must be developed. The use of drought resistant crop cultivars is more expensive and labor-intensive with few advantages. However, exploiting plant growth promoting rhizobacteria (PGPR) is a proven alternative with numerous direct and indirect advantages. The PGPR confers induced systemic tolerance (IST) mechanisms in plants in response to drought stress via multiple mechanisms, including the alteration of root architecture, maintenance of high relative water content, improvement of photosynthesis rate, production of phytohormones, exopolysaccharides, ACC deaminase, carotenoids and volatiles, induction of antioxidant defense system, and alteration in stress-responsive gene expression. The commercial application of PGPR as bioinoculants or biostimulants will remain contingent on more robust strain selection and performance under unfavorable environmental conditions. This review highlights the possible mechanisms of PGPR by activating the plant adaptive defense systems for enhancing drought tolerance and improving overall growth and yield.

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“…Azotobacter sp. are capable of producing siderophore; they bind to the available form of iron Fe + 3 in the rhizosphere, thus making it unavailable to the phytopathogens and protecting the plant health in addition to Hydrogen Cyanide (HCN) production (higher in Azotobacter −77.00%; Nithyapriya et al, 2021 ); exo-polysaccharide production ( Sheikh et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

Synergistic Effect of Azotobacter nigricans and Nitrogen Phosphorus Potassium Fertilizer on Agronomic and Yieldtraits of Maize (Zea mays L.)

Sagar¹,

Sayyed

Ramteke

et al. 2022

Front. Plant Sci.

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Plant growth-promoting bacteria (PGPB) Azotobacter spp. is the most promising bacteria among all microorganisms. It is an aerobic, free-living, and N2-fixing bacterium that commonly lives in soil, water, and sediments. It can be used as a biofertilizer for plant growth and nutrient utilization efficiency. Maize is the highly consumed cereal food crop of the cosmopolitan population, and the sustainable maize productivity achieved by applying bacteria in combination with nitrogen phosphorus potassium (NPK) is promising. In the present study, a bacterial isolate (PR19). Azotobacter nigricans, obtained from the soil of an organic farm was evaluated for its plant growth promoting potential alone and in combination with an inorganic fertilizer (NPK) included. The bacterial cultue (PR19) was screened for its morphological, biochemical, and plant growth-promoting characteristics, sequenced by the 16S rDNA method, and submitted to NCBI for the confirmation of strain identification. Further, the inoculation effect of the bacterial culture (PR19) in combination with NPK on growth and yield parameters of maize under pot were analyzed. Based on phenotypic and molecular characteristics, PR19 was identified as Azotobacter nigricans it was submitted to NCBI genbank under the accession No. KP966496. The bacterial isolate possessed multiple plant growth-promoting (MPGP) traits such as the production of ammonia, siderophore, indole-3-acetic acid (IAA), and ACC Deaminase (ACCD). It showed phosphate solubilization activity and tolerance to 20% salt, wide range of pH 5–9, higher levels of trace elements and heavy metals, and resistance to multiple antibiotics. PR19 expressed significantly increased (p < 0.001) antioxidant enzyme activities (SOD, CAT, and GSH) under the abiotic stress of salinity and pH. In vitro condition, inoculation of maize with the PR19 showed a significant increase in seed germination and enhancement in elongation of root and shoot compared to untreated control. The combined application of the PR19 and NPK treatments showed similar significant results in all growth and yield parameters of maize variety SHIATS-M S2. This study is the first report on the beneficial effects of organic farm isolated PR19-NPK treatment combinations on sustainable maize productivity.

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Extracellular polymeric substances in psychrophilic cyanobacteria: A potential bioflocculant and carbon sink to mitigate cold stress

Cited by 20 publications

References 98 publications

Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation

Pseudomonas aeruginosa inhibits quorum-sensing mechanisms of soft rot pathogen Lelliottia amnigena RCE to regulate its virulence factors and biofilm formation

Insight into Recent Progress and Perspectives in Improvement of Antioxidant Machinery upon PGPR Augmentation in Plants under Drought Stress: A Review

Synergistic Effect of Azotobacter nigricans and Nitrogen Phosphorus Potassium Fertilizer on Agronomic and Yieldtraits of Maize (Zea mays L.)

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