Three different bio-elicitors viz. BE 1, BE 2 and BE 3 were formulated from Fusarium oxysporum f. sp. lycopersici. All three elicitors were screened for defence regulating capacity in an ex vivo system where Lycopersicum esculentum was used as a model host plant. Application of bio-elicitors on detached leaves showed varied degrees of defence induction and antioxidative enzymes and total phenol accumulation after 24 h incubation. Among all, BE 3 (2%) was found to be the most effective. Furthermore, production of nitric oxide (NO) was measured in treated leaves, and concurrently, the extent of oxidative damage was evaluated by measuring reactive oxygen species (ROS), malondialdehyde (MDA), proline and total chlorophyll content. All bio-elicitors except BE 3, which was effective at concentrations as low as 2%, showed enhanced production of MDA and proline and reduction in total chlorophyll at higher concentrations. These results suggest that among three elicitors tested, BE 3 (2%) can be used as a potential bio-elicitor in organic tomato farming. © 2016 Informa UK Limited, trading as Taylor & Francis Group.

KRISHNENDU ACHARYA

Botany

N CHAKRABORTY

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Ex vivo analyses of formulated bio-elicitors from a phytopathogen in the improvement of innate immunity in host

Archives of Phytopathology and Plant Protection

Nitric oxide (NO), a small sized, short lived, highly diffusible natured, gaseous, diatomic and bioactive molecule, has now gained an important position in plant science research, due to its multifunctional roles in physiological as well as pathological responses in plants. A detailed understanding of the molecular mechanisms of plants against various stresses revealed that production of NO and other reactive oxygen species (ROS) are known to interplay an essential role to counter those challenges. NO can directly or indirectly help in the modulation of different protein functions and the reprogramming of defense gene expression by interacting with certain targets. NO might act as a signal in activating ROS-scavenging enzyme activities under various abiotic stresses including drought, salinity, temperature, heavy metal and radiations stress. Furthermore, application of NO donor has tremendous potential to counteract damages in different segments of plants caused by various stresses. This review aims to discuss the overall role of NO in higher plants in response to abiotic stresses. © 2017 Elsevier B.V.

Plant Gene

â€œNO wayâ€! Says the plant to abiotic stress

The objective of this study was to investigate the effectiveness of calcium chloride (CaCl2), as potential elicitor, on tomato plants against Fusarium oxysporum f. sp. lycopersici. Foliar application of CaCl2 showed significant reduction of wilt incidence after challenge inoculation. Increased production of defense and antioxidant enzymes was observed in elicitor treated sets over control. Simultaneously, altered amount of phenolic acids were analyzed spectrophotometrically and by using high performance liquid chromatography. Significant induction of defense-related genes expressions was measured by semi-quantitative RT-PCR. Greater lignifications by microscopic analysis were also recorded in elicitor treated plants. Simultaneously, generation of nitric oxide (NO) in elicitor treated plants was confirmed by spectrophotometrically and microscopically by using membrane permeable fluorescent dye. Furthermore, plants treated with potential NO donor and NO modulators showed significant alteration of all those aforesaid defense molecules. Transcript analysis of nitrate reductase and calmodulin gene showed positive correlation with elicitor treatment. Furthermore, CaCl2 treatment showed greater seedling vigor index, mean trichome density etc. The result suggests that CaCl2 have tremendous potential to elicit defense responses as well as plant growth in co-relation with NO, which ultimately leads to resistance against the wilt pathogen. © 2017, Prof. H.S. Srivastava Foundation for Science and Society.

Fulltext

Physiology and Molecular Biology of Plants

Biochemical basis of improvement of defense in tomato plant against Fusarium wilt by CaCl2

Blister blight disease, caused by an obligate biotrophic fungal pathogen, Exobasidium vexans Massee is posing a serious threat for tea cultivation in Asia. As the use of chemical pesticides on tea leaves substantially increases the toxic risks of tea consumption, serious attempts are being made to control such pathogens by boosting the intrinsic natural defense responses against invading pathogens in tea plants. In this study, the nature and durability of resistance offered by chitosan and the possible mechanism of chitosan-induced defense induction in Camellia sinensis (L.) O. Kuntze plants against blister blight disease were investigated. Foliar application of 0.01% chitosan solution at 15 days interval not only reduced the blister blight incidence for two seasons, but also maintained the induced expressions of different defense related enzymes and total phenol content compared to the control. Defense responses induced by chitosan were found to be down regulated under nitric oxide (NO) deficient conditions in vivo, indicating that the observed chitosan-induced resistance is probably activated via NO signaling. Such role of NO in host defense response was further established by application of the NO donor, sodium nitroprusside (SNP), which produced similar defense responses accomplished through chitosan treatment. Taken together, our results suggest that increased production of NO in chitosan-treated tea plants may play a critical role in triggering the innate defense responses effective against plant pathogens, including that causing the blister blight disease. © 2017 Elsevier Masson SAS

Plant Physiology and Biochemistry

Chitosan-induced immunity in Camellia sinensis (L.) O. Kuntze against blister blight disease is mediated by nitric-oxide

The immunomodulatory role of the natural biopolymer, chitosan, has already been demonstrated in plants, whilst its nanoparticles have only been examined for biomedical applications. In our present study, we have investigated the possible ability and mechanism of chitosan nanoparticles (CNP) to induce and augment immune responses in plants. CNP-treatment of leaves produced significant improvement in the plant's innate immune response through induction of defense enzyme activity, upregulation of defense related genes including that of several antioxidant enzymes as well as elevation of the levels of total phenolics. It is also possible that the extracellular localization of CNP may also play a role in the observed upregulation of defense response in plants. Nitric oxide (NO), an important signaling molecule in plant defense, was also observed to increase following CNP treatment. However, such CNP-mediated immuno-stimulation was significantly mitigated when NO production was inhibited, indicating a possible role of NO in such immune induction. Taken together, our results suggest that CNP may be used as a more effective phytosanitary or disease control agent compared to natural chitosan for sustainable organic cultivation.

Scientific Reports

Chitosan nanoparticles: A positive modulator of innate immune responses in plants

Chilli (Capsicum annuum L.), an economically important crop, suffers from many field and post harvest diseases. Traditional pesticide control is hazardous to the environment, giving rise to the search for alternatives. Our objective was to increase the innate defense molecules in chilli by an abiotic (calcium chloride) and biotic (chitosan) elicitors. Foliar applications of elicitors increased β-1,3 glucanase, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, catalase and phenolics. Treatment with elicitors elicited production of nitric oxide, an important signalling molecule in plant defense. A single application of a nitric oxide donor increased all molecules of innate immunity supporting the role of nitric oxide as the signalling molecule for elicitor mediated increase of innate immunity. © RJPT All right reserved.

Research Journal of Pharmacy and Technology

Boosting of innate immunity in chilli

Effect of sublethal heavy metal stress as plant biotic elicitor for triggering innate immunity in tomato plant was investigated. Copper in in vivo condition induced accumulation of defense enzymes like peroxidase (PO), polyphenol oxidase (PPO), phenylalanine ammonia-lyase (PAL), and β-1,3 glucanase along with higher accumulation of total phenol, antioxidative enzymes (catalase and ascorbate peroxidase), and total chlorophyll content. Furthermore, the treatment also induced nitric oxide (NO) production which was confirmed by realtime visualization of NO burst using a fluorescent probe 4,5-diaminofluorescein diacetate (DAF-2DA) and spectrophotometric analysis. The result suggested that the sublethal dose of heavy metal can induce an array of plant defense responses that lead to the improvement of innate immunity in plants. © 2015 Nilanjan Chakraborty et al.

Scientific World Journal

Sublethal heavy metal stress stimulates innate immunity in tomato

Elicitor-induced natural defense machinery of plants could be proposed as an alternative, non-conventional, and ecologically-friendly approach for plant protection. In this work, the abiotic elicitor, calcium chloride (CaCl<inf>2</inf>), was used for inducing resistance in tea plants against blister blight disease caused by Exobasidium vexans. Foliar application of elicitor resulted in around 80 % disease inhibition over the control set, during the peak time of blister blight incidence at the experimental garden of Darjeeling Tea Research and Development Centre. A significant increase in the activities of defense enzymes like phenylalanine ammonia lyase (PAL), peroxidase, polyphenol oxidase, and β-1,3-glucanase along with higher accumulation of total phenolics was observed. Treated plants also had elevated transcript levels of thaumatin, catalase, PAL, cinnamate 4-hydroxylase, and flavonoid 3′-hydroxylase genes compared to control plants. Further, the treatment-induced nitric oxide (NO) production was confirmed by real-time visualization of the NO burst using a fluorescent probe and spectrophotometric analysis. The result suggested that CaCl<inf>2</inf> induced an array of plant defense responses making this compound a potential phytosanitary product with a challenging issue and a rather attractive option for sustainable organic tea cultivation practice. © 2014, Springer Science+Business Media New York.

Journal of Plant Growth Regulation

Abiotic Elicitor-Mediated Improvement of Innate Immunity in Camellia sinensis

Tea, the second most consumed beverage after water in the world, is produced from the processed tender leaves of tea plants (Camellia sinensis). Production of tea is hindered by various biotic and abiotic stresses. Among the biotic factors, blister blight disease caused by an obligate fungal pathogen, Exobasidium vexans Massee, is a serious problem to the tea industry. The present study was to evaluate the efficacy of elicitor calcium chloride (CaCl2) in inducing resistance in tea plants against blister blight disease. During the pick time of blister incidence at Darjeeling tea garden, the application of CaCl2 at a concentration of 1% resulted in disease inhibition around 71% over the control set. Treatment also resulted in the induction of defence enzymes like peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, β-1,3-glucanase and higher phenol accumulation. Furthermore, the increase in defence molecules also correlated with increase in nitric oxide (NO) generation, a potent defence molecule in plant defence. The result suggests that CaCl2 can used as a potential elicitor in the integrated disease management in organic tea cultivation. © 2014 © 2014 Taylor &amp; Francis.

Journal	Data powered by TypesetArchives of Phytopathology and Plant Protection
Publisher	Data powered by TypesetTaylor and Francis Ltd.
ISSN	0323-5408
Open Access	No