◆Research findings by a group led by Associate Professor Faculty have been published in the online edition of the British international academic journal *Plant Biotechnology Journal*.
Release Date:
Turning Gene "Switches" On and Off with Genome Editing!
A New Approach to Crop Improvement: High Hopes for Applications in Agriculture
[Key Findings of This Study]
・Using genome editing technology (*1), we successfully replaced the promoter (*3) of the " flowering hormone gene FT " (*2)—which is normally active only during the flowering period—with a different promoter that is constantly active. This allowed us to induce early flowering regardless of growing conditions.
・Using this method, it is possible to alter the function of any gene without leaving foreign genetic sequences in the plant, not just for FT. Plants created using this method are considered to be non-GMO and are likely to be socially accepted; therefore, this approach is expected to be applied in the agricultural sector as a new method of crop improvement that allows for the introduction of traits tailored to specific objectives.
[Overview]
A research group led by Associate Professor Michiharu Nakano FacultyGraduate School; Assistant Professor Gaku Nobusawa; Research Assistant Yumi Nagashima; and Professor Makoto Kusaba of Graduate School, has succeeded in “swapping” the promoter regions (the switches that turn gene expression on and off) of different genes within a plant as a new application of genome editing technology.Specifically, in the model plant Arabidopsis thaliana, they swapped the promoter of the " flowering hormone gene FT "—which is normally active only during the flowering period—with the promoter of another gene. This allowed them to induce FT expression (switch ON) even under conditions whereFT expression would not normally be induced (switch OFF), thereby successfully inducing early flowering regardless of cultivation conditions.This marks the first instance in Arabidopsis where a phenotypic change has been successfully achieved through promoter exchange via “chromosomal inversion” (*4) using genome editing.
Since this type of genetic modification falls under the "SDN-1 type" of genome editing (Note 5)—in which no foreign gene sequences remain—it is highly likely that it can be utilized as a non-genetically modified crop following the prescribed review process. Consequently, it is expected to be applied as a new methodology for future crop improvement.
The findings of this study were published online in the British international academic journal *Plant Biotechnology Journal* on May 5, 2025.
[Glossary]
*1 Genome editing
This technology allows for the precise modification of specific locations within an organism’s genetic information (genome). It enables the artificial induction of changes similar to those that occur naturally through mutation.
*2 Flowering Hormone Gene FT
It is one of the key genes that determine when a plant blooms. When FT protein is produced in the leaves and transported to the shoot apical meristem, the plant switches to the flowering phase (reproductive growth).
Note 3: Promoter
These are DNA sequences in the genome that act like "switches" to control when, where, and to what extent genes are expressed.
*4 Chromosomal inversion
This is a phenomenon in which a segment of a chromosome is incorporated into the chromosome in the opposite orientation; it is a mutation frequently observed in nature. The function of genes, particularly those near the inversion breakpoint, may be affected.
*5 SDN-1 Genome Editing
In genome editing, an enzyme called a site-directed nuclease—which acts as a pair of DNA scissors—is used to create a cut at a specific location. Normally, the cell’s own repair mechanisms fully repair the cut, but this method exploits the occasional repair errors that occur to rewrite the genome.These are classified into SDN-1, -2, and -3; the SDN-1 type involves no introduction of foreign genetic sequences and includes mutations of the same kind that occur naturally.
[Paper Information]
Title: Promoter replacement by genome editing creates gain-of-function traits in Arabidopsis
Authors: Takashi Nobusawa, Michiharu Nakano, Yumi Nagashima, Makoto Kusaba
Author: Gaku Nobusawa ( Graduate School; lead author)
Michiharu Nakano ( Faculty, Division of Natural Sciences, Faculty of Education and Research, Kochi University)
Yumi Nagashima ( Graduate School, Hiroshima University)
Shin Kusaba (Hiroshima University, Graduate School Life Sciences, Corresponding Author)
Published in: Plant Biotechnology Journal
[Journal] Plant Biotechnology Journal
[Publication Date] May 5, 2025
[DOI]
This research received a grant from Hiroshima University to cover publication fees.