Towards developing transgenic rice plants tolerant to flooding stress

Rice is a staple food for a large proportion of the world's population. Flooding stress is one of the important abiotic stress factors which adversely affect grain yield of rice crop. In the recent past genetically transformed rice plants have been produced for varied applications including resistance to insects, viruses, fungal pathogens, herbicides, water stress, salt stress and low temperature stress. This development signifies that the methods for introducing useful genes in this important crop are fairly well-established. Flooding stress leads to an encounter of plants with partial (hypoxic) or complete (anoxic) depletion of oxygen. There are several indications that up-regulation of ethanolic fermentation pathway in rice would result in increased flooding tolerance. A battery of genes encoding pyruvate decarboxylase and alcohol dehydrogenase enzymes has been cloned in nee. The present attempts are focussed on altering the capacity of rice cells for alcoholic fermentation through over-expression of these genes. More basic research work is needed in future course to delineate other genes which may have a positive role in imparting flooding tolerance in rice