Japanese scientists have used the revolutionary CRISPR, or CRISPR/Cas9, genome-editing tool to change flower colour in an ornamental plant, the first time the technique has been used for such a purpose.
Researchers from the University of Tsukuba, the National Agriculture and Food Research Organization (NARO) and Yokohama City University, Japan, altered the flower colour of Japanese morning glory (Ipomoea nil or Pharbitis nil), from violet to white, by disrupting a single gene. Japanese morning glory, or Asagao, was chosen as it is one of two traditional horticultural model plants in the National BioResource Project in Japan (NBRP).
The research team targeted a single gene, dihydroflavonol-4-reductase-B (DFR-B), encoding an anthocyanin biosynthesis enzyme, that is responsible for the colour of the plant’s stems, leaves and flowers. Two other, very closely related genes (DFR-A and DRF-C) sit side-by-side, next to DFR-B.
The CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)/Cas9 system is based on a bacterial defence mechanism. It is composed of two molecules that alter the DNA sequence. Cas9, an enzyme, cuts the two strands of DNA in a precise location so that DNA can be added or removed. Cas9 is guided to the correct location by a small piece of RNA that has been designed to be complementary to the target DNA sequence. Currently, CRISPR/Cas9 technology is not 100% efficient, but the mutation rate in this study, 75%, however, was relatively high.
Photo Caption: Morning glory flowers
Photo Credit: tamayura39 / Fotolia