Dr. Genshiro Shiragami was a brilliant geneticists who left Japan to work at the Institute of Biotechnology in Saradia, attempt to use Godzilla cells to stimulate crop growth, as a solution for world hunger. Unfortunately a bomb planted by Bio-Major destroyed all of his work, and also claimed the life of his daughter, Erika. A grief-stricken Shiragami returned to Japan to study plants, in particular a rosebush that he was convinced held his daughter's spirit. During this time he also developed the Anti-Nuclear Energy Bacteria, or ANEB, as a means of controlling radioactive outbreaks.
When the threat of Godzilla returned, Major Sho Kuroki and Lieutenant Goro Gondo requested the use of the ANEB in stopping the monster, but Shiragami hesitated. However when an earthquake destroyed his greenhouse and fatally injured the rosebush harboring Erika's spirit, a distraught Shiragami agreed to the government's plans - in return for being given some sample Godzilla cells to work with as he saw fit. Without the government's consent Shiragami, desperate to save what remained of his daughter, incorporated the rosebush's DNA (and Erika's spirit) together with the Godzilla cells. The end result was the monster Biollante.
In the meantime both Bio-Major and the government of Saradia sought to acquire the ANEB for their own use. After they both failed, the Saradians decided that if they could not have the secret of the ANEB, then no one would, and dispatched an assassin to murder Shiragami. A fatal shot through the heart ended the Doctor's life.