Mutations of OsCOP1, an ortholog of Arabidopsis thaliana CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), were found to cause yellowish pericarp in rice and embryonic death, indicating the vital role of OsCOP1 in the production of flavonoids and rice seed embryo formation. The study is published in Theoretical and Applied Genetics.
Successful production of viable seeds is vital in plant life cycles. However, the seed development process is complex and extremely controlled, impacting various characteristics such as viability and color. To elucidate more about this process, researchers from Seoul National University and partners generated three yellowish-pericarp embryo lethal (yel) rice mutants. The mutant seeds exhibited yellowish pericarps and abnormal embryos, as well as reduced size and weight. Results of genetic analysis and mapping indicated that these characteristics were controlled by the OsCOP1 gene. Using CRISPR-Cas9, OsCOP1 was knocked out, and the transgenic seeds showed yel mutant characteristics. On the other hand, overexpression of OsCOP1 led to the restoration of normal pericarp color, as well as reduced flavonoid accumulation in the embryo and endosperm.
Based on the findings, OsCOP1 is involved in flavonoid biosynthesis and embryogenesis of rice grains.
(Source: Crop Biotech Update, International Service for Acquisition of Agri-Biotech Applications.