Application of Biotechnology to Generate Drought-Tolerant Soybean Plants in Brazil: Development of Genetic Engineering Technology of Crops with Stress Tolerance Against Degradation of Global Environment

Brazil is the second largest soybean-producing country, but yields have recently been unstable because of droughts. The objective of this project was to develop drought-tolerant soybean lines based on information from earlier molecular studies involving model plants. We also searched the soybean genome for genes conferring drought tolerance and elucidated the mechanisms regulating the identified genes. Based on our findings, we generated new soybean lines, which were then evaluated under greenhouse and field conditions to identify the most drought-tolerant lines. We analyzed the functions of drought tolerance genes in Arabidopsis thaliana and identified soybean genes exhibiting similar properties. We also comprehensively investigated soybean gene expression levels in stressed plants. Additionally, we determined the best combinations of drought tolerance genes and promoters and introduced these combinations into soybean cells using biolistic and Agrobacterium tumefaciens-based methods. We evaluated the stress tolerance of the resulting transgenic plants in a greenhouse and in the field and observed that some transgenic soybean lines exhibited increased drought tolerance. We developed a new technique for generating genetically modified soybean lines that are more tolerant to environmental stresses such as drought. These lines may be useful for mitigating the effects of climate changes. The developed technique and generated transgenic soybean lines may help stabilize or increase soybean production in Brazil.