Improvement of Rice Agronomic Traits by Editing Type-B Response Regulators

• Published in: International journal of molecular sciences Vol. 23; no. 22; p. 14165
• Main Authors: Li, Chuanhong, Gong, Chenbo, Wu, Jiemin, Yang, Linfeng, Zhou, Lei, Wu, Bian, Gao, Liang, Ling, Fei, You, Aiqing, Li, Changyan, Lin, Yongjun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 16-11-2022; MDPI
• Subjects: Agricultural production; Bacteria; C-Terminus; CRISPR; CRISPR-Cas Systems - genetics; CRISPR/Cas9; Deoxyribonucleic acid; DNA; Domains; Editing; Gene deletion; Gene Editing - methods; Genes; Genetic modification; Genome editing; Genomes; heading date; Heat resistance; High temperature; Hormones; Kinases; Mutants; Mutation; Oryza - genetics; Oryza - metabolism; Phenotype; Phenotypic variations; Phylogenetics; Plant Breeding; Plants (botany); Plants - genetics; Proteins; quality; Rice; rice breeding; Signal transduction; type-B response regulators; yield; rice breeding; CRISPR/Cas9; heading date; type-B response regulators; yield; quality
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms232214165

Type-B response regulator proteins in rice contain a conserved receiver domain, followed by a GARP DNA binding domain and a longer C-terminus. Some type-B response regulators such as RR21, RR22 and RR23 are involved in the development of rice leaf, root, flower and trichome. In this study, to evaluate the application potential of type-B response regulators in rice genetic improvement, thirteen type-B response regulator genes in rice were respectively knocked out by using CRISPR/Cas9 genome editing technology. Two guide RNAs (gRNAs) were simultaneously expressed on a knockout vector to mutate one gene. T
transformed plants were used to screen the plants with deletion of large DNA fragments through PCR with specific primers. The mutants of CRISPR/Cas9 gene editing were detected by
specific primer in the T
generation, and homozygous mutants without
were screened, whose target regions were confirmed by sequencing. Mutant materials of 12
were obtained, except for
. Preliminary phenotypic observation revealed variations of various important traits in different mutant materials, including plant height, tiller number, tillering angle, heading date, panicle length and yield. The
mutant in the T
generation was then further examined. As a result, the heading date of the
mutant was delayed by about 18 d, while the yield was increased by about 30%, and the chalkiness was significantly reduced compared with those of the wild-type under field high temperature stress. These results indicated that
has great application value in rice breeding. Our findings suggest that it is feasible to perform genetic improvement of rice by editing the type-B response regulators.