Indian Journal of Agricultural Sciences 86 (5): 686–90, May 2016/Article Effect of exogenous iodine on enhancement of oxidative stress in soybean (Glycine max) plant and partial expression of 1-Cys peroxiredoxin gene under heat-stress conditions NEHA GUPTA 1 , MONIKA SHUKLA BAJPAI 2 , RITA SINGH MAJUMDAR 3 and DINESH SINGH 4 Department of Biotechnology, School of Engineering and Technology, Sharda University, Greater Noida, G B Nagar, Uttar Pardesh Received: 7 July 2015; Accepted: 16 November 2015 ABSTRACT The present study analyzes the biochemical effects of exogenous iodine on the antioxidant defense system of soybean (Glycine max L.) plant when grown under heat stress (35ºC). The parameters studied under oxidative stress generation were superoxide anion production, hydrogen peroxide formation and malondialdehyde production. The enzymatic defense was investigated by analyzing the levels of superoxide dismutase, ascorbate peroxidase, catalase and glutathione reductase. For the partial expression of 1-cys peroxiredoxin, the genomic DNA was extracted and primers were designed to amplify the 3’ end region of the PER-1 gene locus 17780502 to 17781727 of genome size 61Mbp, 304 base pairs: PER1-F 5’-ATGCCAGGGATCACACTAGG-3’and PER1-R 5’- ACAAGACAGACCAAGGAGCT-3’ and subjected to PCR. The heat stress generated maximum malondialdehyde without application of iodate and production of superoxide anion was maximum in 80 μM iodate concentration. The H 2 O 2 production was reported highest in 40 μM iodate concentration, Enzymatic defense was highest in 20 and 80 μM dosages of iodate. We amplified 1-cys peroxiredoxin (1-Cys Prx) gene, an important antioxidant enzyme, in soybean plant using primer of an Arabidopsis 1-Cys Prx gene to confer tolerance against heat stress. Key words: 1-Cys peroxiredoxin, Heat stress, Iodine, PCR, Soybean Soybean is one of the most important crops for oil and protein resource. Improvement of stress tolerance will be beneficial for soybean seed production (Wei et al. 2009). Brazil is the second soybean producer and exporter in the world (Borrmann et al. 2009). In plants, the 1-Cys Prxs are highly expressed during late seed development, and the expression pattern is dormancy related in mature seeds (Brehelin et al. 2003). Peroxiredoxins (Prxs), a group of prominent antioxidant enzymes in plants, were first identified in 1996 (Stacy et al. 1996) later, many Prxs were cloned and studied in other plants, such as Arabidopsis (Pulido et al. 2010), rice (Oryza sativa) (Umate 2010), spinach (Spinacia oleracea) (Baier and Dietz 1997). Potassium iodate (KI) has been shown to act as a chemical dessicant (Kumar et al. 2012), which simulates the effect of terminal drought by chemical dessicants during grain filling (Kordenaeej et al. 2013). A number of plants 1 Ph D Student (e mail: nehaguptaa1985@gmail.com), 2 Ph D Student (e mail: shukla.mona@gmail.com), 3 Professor & Head (e mail: majumdar.rita@gmail.com) , Department of Biotechnology. 4 Principal Scientist (e mail: dinesh_iari@rediffmail.com), Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110 012. 126 like lettuce and tomato show an enhanced antioxidant capacity after application of iodine in the form of iodate (Blasco et al. 2011, Kiferle et al. 2013). In previous studies the effect of application of iodine in the form of potassium iodate on the antioxidant system of soybean seeds were reported (Gupta et al. 2015). Prx plays an important role in growth, development and desiccation tolerance in dormant seeds. This paper describes beneficial effect of exogenous iodine in soybean and partial expression of 1-cys peroxiredoxins under heat stress condition. MATERIALS AND METHODS The experiment was conducted in the rainy season of 2013 at the field of Sharda University, Department of Biotechnology, Greater Noida, India. The seeds of soybean were procured from Indian Agriculture Research Institute, Pusa, New Delhi. Seeds were sown in pots carrying soil and cowdung manure in the ratio 3:1. Ten days old seedlings having four-five true leaves were displaced and subjected to heat stress in a growth chamber with conditions of 35°C (day)/33°C (night), 12/12 h (light/dark) photoperiod and light intensity of 72 μmol/m 2 /s. The different treatments were irrigated with the Hoagland nutrient solution. Out of the five experimental pots, three were administered doses of https://doi.org/10.56093/ijas.v86i5.58356