| Rice is an important food crop and the length of fertility is one of the important agronomic traits of rice.Elucidating the molecular regulation mechanism of rice fertility can provide theoretical guidance for breeders to breed new rice varieties with wide adaptation.The OsL1 gene is a candidate gene obtained by using the rice spike development gene microarray,and we used CRISPR/Cas9 technology to target and edit the OsL1 gene in order to analyze the mutant phenotype,expression pattern,and subcellular localization to elucidate its biological function.cellular localization to elucidate its biological functions,the specific findings are as follows.(1)Bioinformatics analysis revealed that OsL1 gene is located on rice chromosome 4,containing 9 exons and 8 introns,with a full length of 4,262 bp,encoding 433 amino acids and a protein molecular weight of 48.7 k D.Sequence comparison and phylogenetic analysis showed that OsL1 belongs to the B3 family of transcription factors and does not contain signal peptide shear sites or transmembrane structural domains.Sequence analysis of the promoter revealed that the gene contains nine light-responsive elements and some hormone-responsive elements,indicating that the gene may be involved in response to plant photoperiod,hormone regulation,tissue development and other related life activities.(2)Targeted editing of OsL1 gene by CRISPR/Cas9 technology was used to screen for thaumatin-free OsL1 gene loss-of-function mutant material.There were no significant differences in fertility,plant height,effective spike,spike grain number,fruit set rate,thousand grain weight and yield per plant between 9522 wild type and OsL1 mutant under natural long daylight conditions in Changsha.Under the natural short daylight conditions in Hainan,the sowing period of the mutant was shortened by 4 days compared with the wild type.There were no significant differences between the mutant and the wild type in yield traits such as effective spike,number of spikes,seed set,and thousand grain weight,but the differences in plant height and yield per plant were significant,with an average reduction of4.6 cm in plant height with the wild type 9522.(3)Using qRT-PCR analysis,OsL1 was found to be expressed in rice roots,stems,leaves,and spikes,with higher expression in root and spike developmental stage 7.The promoter analysis vector p CAMBIA1301-OsL1-GUS was constructed,genetically transformed and transgenic positive plants were obtained,and GUS signals were detected in rice roots,stems,leaves and spikes,and it was hypothesized that the OsL1 gene is constitutively expressed,and subcellular localization studies showed that OsL1 protein is localized in the nucleus.Based on the above experimental results,it is tentatively speculated that OsL1 gene is involved in the regulation of rice tasseling under short daylight conditions,and this study provides a basis for further investigation of the regulation mechanism of OsL1 gene in rice tasseling. |
