The Use of Microorganisms for Gene Transfer and Crop Improvement

Microorganisms have been extensively used in several fields of biomass production in food and medicinal industries and in genetic transformation studies. Steady increase in world population has forced the scientists to meet the increasing demand in food all over the globe. Crop breeding through conventional methods has historically contributed a large extent in improving the yield and quality parameters of almost all edible and industrial crops. Also, a significant degree of credit should be attributed to the modern technologies of biotechnology including genetic transformation technologies via several microorganisms. In this chapter, gene transfer technologies of crop species via both Agrobacterium tumefaciens and A. rhizogenes were reviewed in detail. Also, non-Agrobacterium-based technologies were briefly touched. As to the main focuses of the transformation efforts in plants, the improvements of these traits were studied: herbicide resistance, insect resistance, improved nutritional values, abiotic stress tolerance, and molecular farming/pharming. Finally, virus-induced transient gene expression studies in plants are shortly addressed.