Scientific Area
The role of Phytoglobin-Nitric oxide cycle in anaerobic germination and submergence tolerance of deepwater rice
ID: 613 / 259
Category: Abstract
Track: Pending
Proposed Symposium Title: The role of Phytoglobin-Nitric oxide cycle in anaerobic germination and submergence tolerance of deepwater rice
Authors:
Aprajita Kumari 1, Pooja Singh1, Vemula Chandra Kaladhar1, Manbir, Pradeep Kumar Pathak1, Kapuganti Jagadis Gupta1*
Affiliations: 1 National Institute for Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067, India
Abstract:
Plant encounter low oxygen stress due to flooding/waterlogging or during development of various organs of plants such as seeds. In the environment vast numbers of plant species are prone to flooding. In contrast, plants such as deepwater rice can withstand flooding and submergence. An important and interesting feature of rice is that it can germinate under anoxic conditions. Though several biochemical adaptive mechanisms play an important role in anaerobic germination of rice but the role of phytoglobin-nitric oxide cycle and mitochondrial alternative oxidase pathway is not known. Recently investigated the role of these pathways in anaerobic germination. Under anoxic conditions deepwater rice germinated significantly higher and rapidly than aerobic condition and the anaerobic germination and growth was much higher in the presence of nitrite which is intermediate of nitrate reduction reaction mediated by nitrate reductase. Addition of nitrite to germinating seeds stimulated NR activity and NO production. Important components of phytoglobin-NO cycle such as methaemoglobin reductase activity, expression of Phytoglobin1, NIA1 and the promoters of these genes were elevated under anaerobic conditions in the presence of nitrite. The operation of phytoglobin-NO cycle also accelerated anaerobic ATP generation and fermentation metabolites such as lactic acid production and activity of ADH. Interestingly nitrite significantly reduced ROS production and lipid peroxidation. The reduction of ROS was accompanied by enhanced expression of mitochondrial alternative oxidase protein and its capacity. Application of AOX inhibitor SHAM inhibited the anoxic growth mediated by nitrite. In addition, nitrite improved the submergence tolerance of seedlings. Our study revealed that nitrite driven phytoglobin-NO cycle and AOX are importanrt players in anaerobic germination and submergence tolerance of deepwater rice