Genomics and Genetic Engineering of Rice for Tolerance to Ozone and Anoxia

Rice is one of the dominant staple foods of Southeast Asia; its production has been affected by a number of abiotic and biotic factors. Oxides of nitrogen, carbon monoxide and volatile organic compounds produced from vehicles and industries interact with ultraviolet light and form tropospheric ozone. Excessive ozone in the troposphere and anoxia caused by submergence of plants are two important abiotic stresses causing extensive damage to the rice crop. The physiology and growth of rice is extremely susceptible to ozone stress, which can cause reduction in productivity of the crop. Therefore, it is a call of the time to address these abiotic stresses to safeguard the rice production system. Recent advancements in genomics facilitate the identification of various quantitative trait loci (QTLs) and single nucleotide polymorphisms related with tolerance to both these stressors. It is assumed that the trait is controlled by multiple medium-effect loci rather than by a single large-effect locus. However, the underlying mechanism of stress tolerance is yet to be investigated, or in other words, the target genes that could be engineered in high-yielding varieties are yet to be fished out. The present chapter summarises the available knowledge on molecular physiology of hyper ozone concentration and anoxia tolerance in rice plant.