CHANGES IN ANTIOXIDANT ISOZYMES AS A BIOMARKER FOR CHARACTERIZING HIGH TEMPERATURE STRESS TOLERANCE IN RICE (ORYZA SATIVA L.) SPIKELETS

Abstract

SUMMARYHigh temperature stress at flowering can adversely affect rice yield, largely due to failure of fertilization. Oxidative damage can be a major reason inducing spikelet sterility in rice. In the present study, the effect of high temperatures on antioxidant metabolism in rice spikelets was characterised using nine different genotypes. Exposure to different temperatures at flowering stage revealed significant differences among various antioxidant enzymes in spikelets, both quantitatively and qualitatively. Spikelets of susceptible genotypes withstood temperature stress of up to 35 °C, those of moderately tolerant between 35 °C and 38 °C and those of tolerant genotypes up to 40 °C. Presence or absence, and changes in the isozyme intensities were consistent with alterations in their activities. Superoxide dismutase (SOD) isozymes II and III were present after exposure at 30 °C and 35 °C, while SOD I appeared above 40°C. Intensities of catalase isozymes I and III and the only isozyme of ascorbate peroxidase altered, while the only isozyme of guaical peroxidase and two (III and IV) of the four isozymes of catechol peroxidase disappeared after high temperature exposure of 45 °C. Thus, this work provides an evidence of the role of antioxidant metabolism in spikelets under high temperature stress conditions. Hence, changes in antioxidant isozymes in rice spikelets can be used as a biomarker for characterizing high temperature stress tolerance in rice spikelets.

Variant biochemical responses: intrinsic and adaptive system for ecologically different rice varieties

“…Therefore, all these SOD isoforms have been also identified differentially in various rice seedlings and deviation in SOD activity is also correlated with differential distribution of SOD isoforms (Sharma and Dubey 2005 ; Sharma et al 2013 ; Kaur et al 2016 ). In the present study, the deviation in the SOD activity might also be extrapolated with variation in the ecology involved amongst different rice varieties such as soil salt conditions, pH, waterlogging, lightening, temperature, and atmospheric pressure (Gill and Tuteja 2010 ; Das et al 2013 ; Zhang et al 2015 ; Kaur et al 2016 ; Rossatto et al 2017 ; Abdelaziz et al 2018 ; Xie et al 2019 ).

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Isozyme profiling of Antioxidant Enzyme in Macrotyloma uniflorum

“…Plant tolerance to stress can be studied using isozymes as a biochemical marker (Zhang et al, 2013). Das et al (2013) proposed a hypothesis that higher activities of antioxidant enzymes, coupled with changes in their isozyme profiles in rice spikelets, provide an important mechanism of tolerance to high-temperature stress.…”

Effect of N-acetyl cysteine coated CdS:Mn/ZnS quantum dots on seed germination and seedling growth of snow pea (Pisum sativum L.): imaging and spectroscopic studies

“…When entering a plant, external agents can trigger reactive oxygen species (ROS) production, leading to oxidative stress resulting in antioxidant enzyme production. 16 Qdot, being an external agent, is therefore expected to trigger antioxidant enzyme production, leading to enhanced nutrient uptake and metabolism. This might lead to a change in physiological activities in the plant system.…”