TRANSGENIC ASIATIC GRAIN LEGUMES FOR SALT TOLERANCE AND FUNCTIONAL GENOMICS

Abstract

The Asiatic Vigna species consists of several grain legumes that are native to tropical regions of new world. A number of them are of considerable economic importance in many developing countries. Abiotic stresses such as high salinity and low water availability are major causes of their yield losses and significantly affect their sustainable production. Mungbean (Vigna radiata) and cowpea (Vigna unguiculata) are two of the most important grain legumes of Vigna genus grown in increasingly hostile soil, with salinity and deprived water conditions both expected to worsen in future. Both mungbean and cowpea are classified as glycophytes (salt-sensitive). Exploitation of genetic variation of phenotypic traits through molecular breeding and plant translational genomics, that use knowledge and genes discovered in model plants, could facilitate improving tolerance in these two crops to salinity and drought. High-throughput functional genomics tools, such as transcriptomics, metabolomics, proteomics, and ionomics could be of immense use in investigating the molecular responses to salinity and drought in land races and wild germplasms carrying phenotypic variations for abiotic stress tolerance. Development of salt- and drought-tolerant mungbean and cowpea could play an important role in ensuring in dietary protein supply, improving human health and nutrition, and enhancing ecosystem resilience, especially in developing countries of Asia. In this article, we review and discuss the current knowledge of molecular basis of salt tolerance in model plants and the extent to which they can be implemented in Asiatic grain legumes for improvement to salinity.