CRISPR-mediated acceleration of wheat improvement:advances and perspectives

Common wheat(Triticum aestivum)is one of the most widely cultivated and consumed crops globally.In the face of limited arable land and climate changes,it is a great challenge to maintain current and increase future wheat production.Enhancing agronomic traits in wheat by introducing mutations across all three homoeologous copies of each gene has proven to be a difficult task due to its large genome with high repetition.However,clustered regularly interspaced short palindromic repeat(CRISPR)/CRISPR-associ-ated nuclease(Cas)genome editing technologies offer a powerful means of precisely manipulating the genomes of crop species,thereby opening up new possibilities for biotechnology and breeding.In this review,we first focus on the development and optimization of the current CRISPR-based genome editing tools in wheat,emphasizing recent breakthroughs in precise and multiplex genome editing.We then describe the general procedure of wheat genome editing and highlight different methods to deliver the genome editing reagents into wheat cells.Furthermore,we summarize the recent applications and ad-vancements of CRISPR/Cas technologies for wheat improvement.Lastly,we discuss the remaining chal-lenges specific to wheat genome editing and its future prospects.

The TaTCP4/10-B1 cascade regulates awn elongation in wheat(Triticum aestivum L.)

Awns are important morphological markers for wheat and exert a strong physiological effect on wheat yield.The awn elongation suppressor B1 has recently been cloned through association and linkage analysis in wheat.However,the mechanism of awn inhibition centered around B1 remains to be clarified.Here,we identified an allelic variant in the coding region of B1 through analysis of re-sequencing data;this variant causes an amino acid substitution and premature termination,resulting in a long-awn phenotype.Transcriptome analysis indicated that B1 inhibited awn elongation by impeding cytokinin-and auxinpromoted cell division.Moreover,B1 directly repressed the expression of TaRAE2 and TaLks2,whose orthologs have been reported to promote awn development in rice or barley.More importantly,we found that TaTCP4 and TaTCP10 synergistically inhibited the expression of B1,and a G-to-A mutation in the B1 promoter attenuated its inhibition by TaTCP4/10.Taken together,our results reveal novel mechanisms of awn development and provide genetic resources for trait improvement in wheat.