Bioprospecting and genetic engineering of mangrove genes to enhance salinity tolerance in crop plants

Abstract

Salinity in agricultural land is a major problem world wide, placing a severe constraint on crop growth and productivity in many regions and increased salinization of arable land is expected to have devastating global effects. Though plants vary in their sensitivity to salt stress, high salinity causes water deficit and ion toxicity in many plant species. Considerable efforts have therefore been made to investigate how genes respond to salt stress in various plants by using several approaches, including proteomics. Proteomic approaches for identifying proteins that are regulated in response to salt stress are becoming common in the post-genomics era of crop research. In this chapter, a detailed description of physiological, biochemical and antioxidative genes of salt stress in mangroves is given. Recent developments on salt stress genes of mangrove origin are also discussed and their identification applying bioinformatics approach as well as their validation in lower unicellular organisms. In addition, genomic biological changes in the proteomes of mangroves under salt stress condition are discussed. This chapter will provide a viewpoint into how proteomics and genomic based research is likely to develop in this field. Accumulation of compatible solutes and induction of antioxidative enzymes are other mechanisms of salt tolerance in mangroves. Mangroves also provide a reservoir for some of the best known, and at times, novel genes and proteins, involved in tolerance to salinity stress, that are likely at work in other plants. The salt tolerance genes listed in this review most likely represent only the tip of the iceberg, and continuous efforts to isolate and identify novel useful genes and promoters from mangroves are necessary; DNA microarray technology in particular is likely to become a powerful tool for this purpose. Eventually, the largest challenge will be to combine these genes and promoters in a systematic and logical way in order to maximize plant salinity tolerance. When realized, genetic engineering of crop and industrial plant for salinity tolerance using genes isolated from mangroves will be a vitally important tool in the quest to alleviate the earth's future problems concerning food, energy, and the environment.