The growth period (especially the flowering period) is one of the important factors affecting the distribution and yield of soybean varieties. The excavation and research of genes regulating the growth period of soybeans is vital to the selection of excellent soybean varieties with wide ecological adaptability. So far, many E-series genes that regulate the growth period of soybeans have been cloned. Their application has improved breeding efficiency and yield. However, due to the complexity of photoperiod regulation of soybean flowering, there are still many important genes for growth periods that have not been discovered. The specific regulatory mechanism Still unclear.
The Soybean Molecular Design and Breeding Discipline Group of the Northeast Institute of Geography has long been committed to the discovery of new flowering genes. Assistant researcher Wang Feifei used the MA recombinant inbred line constructed after the crossing of Minsoy (E1e2e3E4) and Archer (e1ase2E3E4) to flower under long-day conditions Phase QTL detection, through parental resequencing and MA population SLAF-seq, combined with the flowering phenotype of MA population, detected an important regulatory site TOF7 (Time of Flowering 7). Further studies have shown that this locus is controlled by a single gene, and the coding gene TOF7 controls early flowering and early maturity. Its candidate gene is a homologous gene of a key circadian clock gene in the flowering pathway of Arabidopsis thaliana. TOF7 is a new site for controlling the flowering of soybeans, named E11 by the World Soybean Council, and its genetic characteristics of E11/e11 are recognized by the Soybean Council.
Dr. Li Zhaobo used Genome-wide association studies (GWAS) technology to perform homology comparison with Arabidopsis important circadian clock genes and identified a new gene LNK2 (Night light -inducible and clock-regulated 2). Using CRISPR/Cas9, a transgenic quadruple homozygous mutant of the LNK2 gene was developed. Under long-day conditions, the flowering time of the quadruple mutant was significantly earlier than that of the wild type. Fluorescence quantitative PCR showed that under long-day conditions, the transcription level of LNK2 was significantly lower than that of the wild type. LNK2 promoted the expression of legume-specific E1 gene and inhibited the expression of florin FT2a. These results indicate that CRISPR/CAs9-mediated targeted mutations of 4 LNK2 genes shortened the flowering time of soybeans.
The findings of this study add new members to control the flowering time of soybeans, which will further improve the soybean flowering regulatory network and provide genetic resources and theoretical basis for soybean molecular design and breeding. This research was funded by the National Natural Science General Project (No. 31972966) and the National Key Research and Development Project (2017Y FD0101305).
Zhaobo Li, Qun Cheng, Zhuoran Gan et al., Multiplex CRISPR/Cas9-mediated knockout of soybean LNK2 advances flowering time. The Crop Journal, 2020, https://doi.org/10.1016/j.cj.2020.09 .005
Feifei Wang, Haiyang Nan, Liyu Chenet al., A new dominant locus, E11, controls early flowering time. Molecular breeding, 2019, 39:70