Genome Editing in Species of the Tribe Triticeae with the CRISPR/Cas System

The tribe Triticeae includes important agricultural crops, such as bread wheat, durum wheat, barley, rye, and triticale. Research in the field of reverse genetics and genetic engineering of Triticeae received a new impetus as the CRISPR/Cas genome editing system came into broad use. The review describes and analyzes the data on recent advances in genomic editing of cultivated plants of the tribe Triticeae and tools used in the field. The tools most commonly used for genome editing in Triticeae include the codon-optimized Cas9 gene under the control of the maize ubiquitin gene promoter and guide RNAs under the control of Pol III promoters U6 and U3 in one or more binary vectors. Phosphinothricin and hygromycin resistance genes are used as selectable genes. Agrobacterium-mediated transformation and biolistics are performed to obtain genome-edited plants, and immature embryos are used as explants. Approaches developed to overcome the problem of low regenerative capacity of Triticeae include in planta transformation of shoot apical meristems, transformation of microspores and pollen grains, and the use of haploinductors. Bread wheat and barley were subject to genomic editing in the majority of studies published to date, and durum wheat and triticale were recently used in CRISPR/Cas knockout studies of target genes. Further progress in the development of genome editing of cultivated plants of the tribe Triticeae should be aimed at expanding the range of species and varieties involved and overcoming the problems of low regenerative capacity. This will allow genetic modification of elite varieties, which will be in demand in agricultural production.

Automated summary

This review discusses recent advances in genomic editing of cultivated plants in the Triticeae tribe, with a focus on bread wheat and barley. It also examines the tools and methods commonly used in this field, as well as approaches to overcome the low regenerative capacity observed in Triticeae plants.