2012 Volume 7 Issue 1 Pages 103-110
‘Food security’ has always been a prime issue for the development and progress of human civilization. However, in spite of all technological, scientific, and agricultural achievements the secure and affordable supply of safe and nutritious food to the population is still in an alarming state. In the year 2007 alone, the number of hungry people increased by 75 million and expected to reach to 1.2 billion worldwide by 2017. Among the various reasons responsible for rising food crisis, ‘global environmental change’ can be considered as one of the most critical factors today. Among the environmental factors, increasing tropospheric or surface level ozone (O3) levels has been recognized as a major cause for declining plant growth and crop yield. According to the IPCC (2007) report, concentration of tropospheric O3 is estimated to have increased from approximately 10 ppb prior in the industrial revolution to a current level of about 60 ppb during summer months, and is predicted to increase 20-40% more by 2050 in the industrialized countries of the Northern Hemisphere. Like other tropical countries, India is also under the severe threat of O3 pollution.
The present review mainly focuses on the responses of rice (Oryza sativa L. cultivars - Malviya dhan 36 and Shivani) and wheat (Triticum aestivum L. cultivars - Sonalika and HUW 510) plants to elevated levels of O3-stress at Indian context through a combination of physiology and high-throughput proteomics analyses using open top chambers (OTCs). Experimental sets were prepared as: filtered chambers (FCs) with almost negligible O3, non-filtered chambers (NFCs) with ambient O3, non-filtered chambers with 10 ppb O3 fumigation (NFCLOs), and non-filtered chambers with 20 ppb O3 fumigation (NFCHOs). Notably, O3 causes significant induction in major cellular antioxidants, and negatively affects photosynthetic machinery in both rice and wheat plants. Proteomics analysis revealed that O3 strongly inhibits the expression of major photosynthetic and important energy metabolism proteins, and induced the defense or stress related proteins. Proteomics, writing simply, refers to the study of all the proteins in a cell, tissue or organism, and is part of three young, high-throughput ‘omics’ technologies of genomics (transcriptomics), proteomics, and metabolomics. Random Amplified Polymorphic DNA (RAPD) analysis also revealed significant damage in genome template stability of both the crops under O3 stress, hence indicating toward the mutagenic ability of O3.
We believe that present results are a small but necessary step forward in developing O3-tolerant rice and wheat genotypes, which can be utilized in the future high O3 world for their optimum growth and yield.
