Choi researched jasmonates, which are believed to participate in signal transduction processes between external stresses, such as wounding, pathogenic attack, or cell response by activating the defense genes. He discovered a new enzyme, (EC2.1.1.141) jasmonate carboxyl methyltransferase (JMT), which catalyzes the methylation of jasmonate to MeJA. The overexpression of the JMT gene confers resistance to pathogens. He is currently working to understand the molecular function of MeJA, JMT, and its effector genes. Furthermore, the genetic engineering of crops by application of those genes and knowledge is under investigation.
The major research activity is the discovery of a novel enzyme and its genes encoding jasmonic acid carboxyl methyltransferase, which is involved in stress response and signal transduction in plant. Other achievements are the development of drought tolerant transgenic rice and transferred technology to Mahyco, India and the development of yield-enhanced transgenic rice and transferred technologies to BASF Plant Science in Germany.