Publications of NIPGR Scientists

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Subject: search.filters.subject.Antioxidant enzymes

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    Heat stress mitigation by silicon nutrition in plants: A comprehensive overview
    (Springer Nature Publishing AG, 2023) Shilpha, Jayabalan; Manivannan, Abinaya; Soundararajan, Prabhakaran; Jeong, Byoung Ryong
    Rapid climatic changes have exacerbated the severity of extreme weather events in agricultural regions, such as rainfall, elevated temperatures, and drought stress. As a result, heat stress (HS) has emerged as one of the most serious abiotic risks to crop development, productivity, and nutritional security due to the continued rise in global mean temperature. According to the IPCC, average global temperatures will rise by 3–6 °C by 2100. Importantly, excessive temperature stress during the reproductive stage results in a significant reduction of crop output. Consequently, there is an urgent need to comprehend food crops’ response and tolerance mechanisms to heat stress. Plants respond to high-temperature stress by initiating a series of physiological, biochemical, and molecular events and adapt by activating many stress-responsive genes. Silicon (Si) is a subtle element that improves plant growth and development and protects it against numerous abiotic and biotic challenges. Several studies have proved that the exogenous application of Si has significantly mitigated the negative impacts of abiotic stresses. However, there have only been a few investigations on the Si’s role in reducing the deleterious consequences of heat stress. Therefore, this chapter summarizes the heat-induced responses and damages in plants. In a few examples, we discuss the versatile functions of Si in mitigating abiotic stresses, including heat stress and Si-mediated molecular mechanisms of heat stress tolerance.
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    A protein repairing enzyme, PROTEIN L- ISOASPARTYL METHYLTRANSFERASE is involved in salinity stress tolerance by increasing efficiency of ROS-scavenging enzymes
    (Elsevier B.V., 2020) Ghosh, Shraboni; Kamble, Nitin Uttam; Majee, Manoj
    Saline conditions can significantly affect plant growth and development, leading to massive reduction in crop yield. Herein, we show that a protein repairing enzyme PROTEIN L-ISOASPARTYL METHYLTRANSFERASE imparts salinity stress tolerance in Arabidopsis thaliana by repairing deleterious isoAsp accumulation during salinity stress. We demonstrate that salinity stress accelerates isoAsp accumulation in proteins and also induces PIMT activity in Arabidopsis. Transcript analysis indicates that both PIMT1 and PIMT2 are upregulated in response to salinity stress. Subsequent functional analysis reveals that PIMT1 and PIMT2 overexpression lines are tolerant, while RNAi lines are hyper sensitive to salinity stress in comparison to wild type (WT). Biochemical analyses of thesePIMT transgenic lines also reveals that compromised salinity tolerance of RNAi lines are linked to increased isoAsp accumulation, while improved tolerance of overexpression lines is associated with reduced isoAsp accumulation in proteins. Histochemical and biochemical studies further confirm lower accumulation of ROS and reduced lipid peroxidation in PIMT overexpression lines, while increased ROS accumulation and increased lipid peroxidation in RNAi lines as compared to WT under salinity stress. Interestingly, PIMToverexpression lines exhibit improved antioxidant enzyme efficiency, while RNAi lines display compromised antioxidant enzyme efficacy as compared to WT type plants. Our study suggests that PIMT improves salinity stress tolerance by restricting salt induced-excess ROS accumulation possibly by repairing isoAsp mediated protein damage of antioxidant enzymes. Our study can be utilized for enhancing salinity stress tolerance of economically important crops.
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    A comprehensive study on dehydration-induced antioxidative responses during germination of Indian bread wheat (Triticum aestivum L. em Thell) cultivars collected from different agroclimatic zones
    (Springer Science, 2012) Garg, Bharti; Jaiswal, Jai P.; Misra, Shrilekha; Tripathi, Bhumi Nath; Prasad, Manoj
    To explore the adaptability of bread wheat to dehydration stress, we screened 28 cultivars collected from different agroclimatic zones, on the basis of malonaldehyde content as biochemical marker in roots of wheat seedlings during germination and classified them as highly tolerant, tolerant, sensitive and highly sensitive. From this primary screening, ten cultivars that showed differential responses to dehydration stress were selected to understand the biochemical and physiological basis of stress tolerance mechanisms. The highly tolerant cultivars showed lower levels of lipid peroxidation, less membrane damage, increased levels of antioxidants, enzymes like catalase, ascorbate peroxidase, glutathione reductase activities, and maintained higher relative water content in comparison to sensitive cultivars, indicating better protection mechanism operating in tolerant cultivars. Correspondingly, highly tolerant cultivars exhibited more accumulation of proline and less H2O2 content across different time points of polyethylene glycol treatments in comparison to sensitive ones. The above biochemical and physiological parameters were further validated through northern analysis of catalase (CAT1) gene, that showed differential expression patterns in tolerant and sensitive cultivars largely in confirmation with the biochemical and physiological analyses. Our study positively correlates the differences in the redox status and antioxidant defense system between tolerant and sensitive cultivars for the establishment of wheat seedlings in typical dehydration conditions.
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    Differential responses of arsenic stress in two varieties of Brassica juncea
    (Elsevier B.V., 2009) Gupta, Meetu; Sharma, Pallavi; Sarin, Neera Bhalla; Sinha, Alok Krishna
    Present study showed the toxicity caused by Arsenite (As(III)) and its detoxification responses in two varieties (Varuna and Pusa Bold) of Brassica juncea. Comparisons were made in leaves and roots of both the varieties, which showed that the accumulation pattern in both the varieties were dose and duration dependent, being more in roots for two days and in leaves for four days. Increase/decrease of antioxidant enzymes activities (SOD, CAT, GPX) showed not much changes at the given concentrations except that the enzyme activities showed significant increase at the lower concentrations. Semi quantitative RT-PCR analysis of PCS showed more expression of its transcript in P. Bold as compared to Varuna variety due to As(III) stress. The analysis of isoenzyme pattern in leaves of P. Bold showed five and two major bands of SOD and GPX, respectively. As(III) treatment leads to the activation of MAPK activity indicating role of this important cascade in transducing As(III) mediated signals. The data presented indicates the differential responses in both the varieties and also that the increased tolerance in P. Bold may be due to the defensive role of antioxidant enzymes, induction of MAPK and up regulation of PCS transcript which is responsible for the production of metal binding peptides.