Acquisition of seed dormancy breaking in rice (Oryza sativa L.) via CRISPR/Cas9-targeted mutagenesis of OsVP1 gene

Genome editing offers great advantages in identifying gene function and generating agronomical important mutations in crops. Here, we report the development of edited lines with reduced seed dormancy by knockout viviparous-1 (OsVP1) gene known as a transcription factor that regulates key aspects of plant seed development and ABA signaling in rice. Thirty-three genetic edited lines out of 55 T-0 rice plants were generated using CRISPR/Cas9 system. Sequencing analysis showed that the plants had four different mutation types at the target site of OsVP1, the mutations were found to be transmitted to the succeeding generations. Stable transmission of CRISPR/Cas9-mediated mutant lines without the transferred DNA (T-DNA) was confirmed by segregation in the T-1 generation. Regarding many investigated agronomic trait, there are no significant differences between homozygous mutants and wildtype plants under field's growth conditions. Especially in RT-PCR analysis of ABA/GA signaling genes, the expression of OsNCED2, OsGA20ox1, OsGA20ox2, OsGA20ox3 genes in homozygous mutants was increased compared to wildtype plants. Results of this study exemplified the effectiveness of CRISPR/Cas9 as a gene editing tool in broke down the seed dormancy in rice.