Plant Process and Function

en Rapid response of rice plants to arsenite toxicity Rapid response of rice plants to arsenite toxicity تنش فلزات سنگین Toxic ions stress پژوهشي Research Absorption of arsenic (As) by plant root is an essential activity that bridges the soil As concentration and physiological responses which can be monitored soon after exposure to As. In the present study, physiological responses to short exposure to arsenite (AsIII) was compared in two indigenous rice cultivars one adapted to temperate and humid (TH) and the second one to warm and humid (WH) climates. Twenty day-old plants were exposed to 75 µM AsIII, 6h. Expression of certain transporters, antioxidant system, and As detoxifying proteins were noticeable. The levels of aquaporin transcripts OsNIP 2;1 (Lsi1), OsPIP1; 3, and OsPIP2;6 significantly decreased in both cultivars. A more prominent reduction of aquaporin transcripts was observed in the WH cultivar and was accompanied by a lower AsIII uptake as compared to the TH. The activity of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase enhanced in both cultivars, indicating the attempts to protect plants against AsIII-induced oxidative damage. These antioxidant responses were more pronounced in the WH cultivar and were accompanied by remarkably enhanced levels of reduced glutathione (a non-protein thiol) and phytochelatin, particularly in shoots. Although both cultivars responsed to AsIII very rapidly, based on the data presented here, it is likely that long-term adaptation of WH cultivar to warm and humid climate has driven genomic changes resulting in AsIII sequestration and other protective strategies against AsIII toxicity. Absorption of arsenic (As) by plant root is an essential activity that bridges the soil As concentration and physiological responses which can be monitored soon after exposure to As. In the present study, physiological responses to short exposure to arsenite (AsIII) was compared in two indigenous rice cultivars one adapted to temperate and humid (TH) and the second one to warm and humid (WH) climates. Twenty day-old plants were exposed to 75 µM AsIII, 6h. Expression of certain transporters, antioxidant system, and As detoxifying proteins were noticeable. The levels of aquaporin transcripts OsNIP 2;1 (Lsi1), OsPIP1; 3, and OsPIP2;6 significantly decreased in both cultivars. A more prominent reduction of aquaporin transcripts was observed in the WH cultivar and was accompanied by a lower AsIII uptake as compared to the TH. The activity of superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase enhanced in both cultivars, indicating the attempts to protect plants against AsIII-induced oxidative damage. These antioxidant responses were more pronounced in the WH cultivar and were accompanied by remarkably enhanced levels of reduced glutathione (a non-protein thiol) and phytochelatin, particularly in shoots. Although both cultivars responsed to AsIII very rapidly, based on the data presented here, it is likely that long-term adaptation of WH cultivar to warm and humid climate has driven genomic changes resulting in AsIII sequestration and other protective strategies against AsIII toxicity. Aquaporin, Antioxidant system, Arsenite, Rice, Thiol compounds Aquaporin, Antioxidant system, Arsenite, Rice, Thiol compounds 19 28 http://jispp.iut.ac.ir/browse.php?a_code=A-10-99-8&slc_lang=en&sid=1 Mahdi Yousofinia Mahdi Yousofinia No Department of Plant Biology, Faculty of Biological Science, Tarbiat Modares University (TMU), Department of Plant Biology, Faculty of Biological Science, Tarbiat Modares University (TMU) Faezeh Ghanati Faezeh Ghanati ghangia@modares.ac.ir 0000-0002-2901-0152 Yes Department of Plant Biology, Faculty of Biological Science, Tarbiat Modares University (TMU), Department of Plant Biology, Faculty of Biological Science, Tarbiat Modares University (TMU), Meisam Jafarzadeh Meisam Jafarzadeh No Department of Molecular Genetics, Faculty of Biological Science, Tarbiat Modares University Department of Molecular Genetics, Faculty of Biological Science, Tarbiat Modares University