Strategies to Co-express Two Genes Encoding Functionally Related Proteins for Osmolyte Biosynthesis and Ion Homeostasis: Does the Conventional Crossing Method have an Advantage Over the Tissue Culture Technique to Develop Co-expressed Transgenics for Stress Tolerance?

Transgenic technology has given a real boost to modern biotechnology by making it possible to transform a plant from susceptible to resistant to many stresses. In order to pyramid genes to improve the stress response, single transformants can either be crossed to pyramid the genes or a multigene vector can be generated and the plants transformed. The present paper presents case studies of both single- and multi- gene transgenics developed by two approaches, crossing and the use of multigene constructs. Whatever the strategy, the concept of the multigene strategy has come to stay with its limitless potential.