Browsing by Author "Rashmi Tewari"

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Defense Inducers Mediated Mitigation of Bacterial Canker in Tomato through Alteration in Oxidative Stress Markers
(MDPI, 2022) Ruchi Tripathi; Karuna Vishunavat; Rashmi Tewari; Sumit Kumar; Tatiana Minkina; Ugo De Corato; Chetan Keswani
The bacterial canker disease of tomato caused by Clavibacter michiganensis subsp. michiganensis (Cmm) has been reported to adversely affect the tomato cultivation in the NE hilly regions of India. Defense inducers such as salicylic acid (SA), isonicotinic acid (INA), benzothiadiazole (BTH) and lysozyme were used as prophylactic and curative sprays at different concentrations to test their efficacy in inducing resistance in tomato plants against Cmm under protected conditions. The induced resistance was studied through the alteration in the activities of oxidative stress marker enzymes (PAL, PO, PPO, TPC and PR-2 protein), hydrogen peroxide formation in leaf tissues and lignin accumulation in stem tissues, as well as through the reduction in disease severity under glasshouse conditions. The results of the present study revealed that the enzymatic activity, hydrogen peroxide formation and lignin production were significantly higher in the BTH (500 ppm)-treated leaves than in those observed in the control. The lowest disease incidence was recorded when BTH was applied as a prophylactic spray (27.88%) in comparison to being applied as a curative spray (53.62%), thereby suggesting that a defense inducer, BTH, shows antibacterial activity against Cmm, reduces disease incidence severity and induces defense responses in the tomato plant. © 2022 by the authors.
Trichoderma Koningii enhances tolerance against thermal stress by regulating ROS metabolism in tomato (Solanum lycopersicum L.) plants
(Taylor and Francis Ltd., 2021) Ruchi Tripathi; Chetan Keswani; Rashmi Tewari
Thermal stress (TS) can be detrimental to tomato crop at different growth stages and is accounted by the generation of highly fatal reactive oxygen species (ROS). In this study, the effects of Trichoderma koningii ITCC 5201 (TK) were investigated on the tolerance of tomato (Solanum lycopersicum L.) plants under TS. TS elevated SOD, POD, PPO PAL, and Proline activity in the present study. However, a further reduction was observed in these enzymatic activities by the application of TK in the stressed and treated seedlings, while an increase in the starch, protein, and total phenol content was observed in stressed and treated plants. TS affirms the increase in H2O2 generation and lignin deposition, but reduction in the accumulation was observed by the treatment of TK to tomato seeds. In conclusion, TK proved to be very beneficial in imparting resistance to the tomato plants against heat stress through improved modulation of antioxidants. © 2021 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.