Researchers in Japan used CRISPR/Cas9 to disable a key anthocyanin-pathway gene in red leaf lettuce, eliminating the red coloration and increasing levels of some other flavonoids without detectable growth penalties under controlled indoor conditions.
Scientists at the University of Tsukuba used CRISPR/Cas9 genome editing to knock out DFR (dihydroflavonol 4-reductase) in red leaf lettuce (Lactuca sativa L. cv. “Red Fire”), a gene involved in the biochemical pathway that produces anthocyanins, the pigments that give red lettuce its color.
In the resulting edited lines, the team reported a complete loss of red pigmentation and a visually distinct green phenotype, alongside lower anthocyanin levels. Metabolite profiling indicated that the alteration was associated with a shift in flavonoid composition, including increased accumulation of flavonoids such as quercetin and higher total flavonoids in some edited lines.
The researchers also reported no significant negative effects on growth traits measured under plant-factory-style conditions (including metrics such as shoot dry weight and leaf number), suggesting the pigment change did not come with a detectable growth penalty in the tested controlled-environment system.
The work was published in Frontiers in Genome Editing as “CRISPR/Cas9-mediated knockout of DFR alters pigmentation and shifts flavonoid accumulation in red leaf lettuce without detectable growth penalties.” The University of Tsukuba said the research in Hiroshi Ezura’s group was funded through the Japan Science and Technology Agency’s OPERA program (JSTOPERA, JPMJOP1851).
