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.

KRISHNENDU ACHARYA

Botany

N CHAKRABORTY

S CHANDRA

Fulltext

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

Sublethal heavy metal stress stimulates innate immunity in tomato.

Scientific World Journal

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.

Physiology and Molecular Biology of Plants

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

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.

Archives of Phytopathology and Plant Protection

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

Improvement of the host resistance by using hazard free chemical elicitors is emerging as an alternative approach in the field of plant disease management. In our present work, we have screened the efficacy and possible mechanism of abiogenic elicitors like Dipotassium hydrogen orthophosphate (K2HPO4), Oxalic acid (OA), Isonicotinic acid (INA), Salicylic acid (SA), Acetylsalicylate (AS), Arachidonic acid (AA) and Calcium chloride (CaCl2) to stimulate innate immune responses in Lycopersicum esculentum Mill. Excised tomato leaves, treated with elicitors at three different concentrations, were found to stimulate defense and antioxidative enzymes, total phenol and flavonoid content after 24 h of incubation. CaCl2 (0.5 %) followed by INA (2.5 mM) were found most effective in activation of all such defense molecules in tomato leaves. Furthermore, nitric oxide (NO), a key gaseous mediator in plant defense signaling, was also measured after subsequent elicitor application. Higher doses of elicitors showed an elevated level of reactive oxygen species (ROS) generation, enhanced lipid peroxidation rate and proline content, which indicates the extent of abiotic stress generation on the leaves. However, ROS production, lipid peroxidation rate and proline concentration remain significantly reduced as a result of CaCl2 (0.5 %) and INA (2.5 mM) application. A sharp increase of total chlorophyll content was also recorded due to treatment of CaCl2 (0.5 %). These results demonstrate the effects of different abiogenic elicitors to regulate the production of defense molecules. Results also suggest that among all such chemicals, CaCl2 (0.5 %) and INA (2.5 mM) can be used as a potential elicitor in organic farming of tomato. © 2016, Prof. H.S. Srivastava Foundation for Science and Society.

Abiotic elicitors mediated elicitation of innate immunity in tomato: an ex vivo comparison

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

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

The objective of this work was to search out the probable molecule behind the activation of broad spectrum resistance during abiotic elicitors such as arachidonic acid, cupric chloride, chitosan, isonicotinic acid and salicylic acid mediated induced systemic resistance (ISR) in Raphanus sativus L. The elicitor compounds were sprayed on the radish leaves of healthy plant and after 24 h incubation a significant increase of β-1,3 glucanase, peroxidase, polyphenol oxidase and phenolics as well as a remarkable increase of nitric oxide (NO), a probable potent defense-signaling molecule in plant, was observed. Furthermore, treatment of the host with NO donor, sodium nitroprusside, also induced the same defense molecules. The results suggests that NO might be the signaling molecule during abiotic elicitor mediated ISR induction in the host system. © 2011 Taylor & Francis.

Signaling role of nitric oxide in the induction of plant defense by exogenous application of abiotic inducers

The study was aimed to search out the probable molecule behind the activation of a broad spectrum resistance during Pseudomonas aeruginosa WS-1 mediated induced systemic resistance (ISR) in Capsicum annuum where plants were challenged inoculated with its pathogen Colletotrichum capsici 24 h after induction of ISR. On the fourth day after pathogen inoculation a significant increase of pathogenesis-related (PR) proteins, other defence enzymes and phenolics as well as a two-fold increase of nitric oxide (NO) a potent defence signalling molecule were observed. Treatment of the host with NO donor also induced the same defence molecule in a similar manner. Results suggest the possible signalling role of NO in ISR during crosstalk between ISR inducing agent and pathogen within the host system. © 2011 Taylor & Francis.

Journal	Scientific World Journal
Publisher	Hindawi Publishing Corporation
ISSN	2356-6140
Open Access	No