Epistatic determinism of durum wheat resistance to the wheat spindle streak mosaic virus

CRISPR/Cas9 genome editing in wheat: enhancing quality and productivity for global food security-a review

Wheat (Triticum aestivum L.) is an important cereal crop that is grown all over the world for food and industrial purposes. Wheat is essential to the human diet due to its rich content of necessary amino acids, minerals, vitamins, and calories. Various wheat breeding techniques have been utilized to improve its quality, productivity, and resistance to biotic and abiotic stress impairing production. However, these techniques are expensive, demanding, and time-consuming. Additionally, these techniques need multiple generations to provide the desired results, and the improved traits could be lost over time. To overcome these challenges, researchers have developed various genome editing tools to improve the quality and quantity of cereal crops, including wheat. Genome editing technologies evolve quickly. Nowadays, single or multiple mutations can be enabled and targeted at specific loci in the plant genome, allowing controlled removal of undesirable features or insertion of advantageous ones. Clustered, regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein (Cas) is a powerful genome editing tool that can be effectively used for precise genome editing of wheat and other crops. This review aims to provide a comprehensive understanding of this technology's potential applications to enhance wheat's quality and productivity. It will first explore the function of CRISPR/Cas9 in preserving the adaptive immunity of prokaryotic organisms, followed by a discussion of its current applications in wheat breeding.

Resistance of QYm.nau-2D to wheat yellow mosaic virus was derived from an alien introgression into common wheat

The QYm.nau-2D locus conferring wheat yellow mosaic virus resistance is an exotic introgression and we developed 11 diagnostic markers tightly linked to QYm.nau-2D. Wheat yellow mosaic virus (WYMV) is a serious disease of winter wheat in China. Breeding resistant varieties is the most effective strategy for WYMV control. A WYMV resistant locus QYm.nau-2D on the chromosome arm 2DL has been repeatedly reported but the mapped region is large. In the present study, we screened recombinants using a biparental population and mapped QYm.nau-2D into an 18.8 Mb physical interval. By genome-wide association studies of 372 wheat varieties for WYMV resistance in four environments, we narrowed down QYm.nau-2D into a 16.4 Mb interval. Haplotype analysis indicated QYm.nau-2D were present as six different states due to recombination during hybridization breeding. QYm.nau-2D was finally mapped into a linkage block of 11.2 Mb. Chromosome painting using 2D specific probes and collinearity analysis among the published sequences corresponding to QYm.nau-2D region indicated the block was an exotic introgression. The Illumina-sequenced reads of four diploid Aegilops species were mapped to the sequence of Fielder, a variety having the introgression. The mapping reads were significantly increased at the putative introgression regions of Fielder. Ae. uniaristata (NN) had the highest mapping reads, suggesting that QYm.nau-2D was possibly an introgression from genome N. We investigated the agronomic performances of different haplotypes and observed no linkage drag of the alien introgression for the 15 tested traits. For marker-assisted selection of QYm.nau-2D, we developed 11 diagnostic markers tightly linked to the locus. This research provided a case study of an exotic introgression, which has been utilized in wheat improvement for WYMV resistance.

Bymovirus-induced yellow mosaic diseases in barley and wheat: viruses, genetic resistances and functional aspects

Bymovirus-induced yellow mosaic diseases seriously threaten global production of autumn-sown barley and wheat, which are two of the presently most important crops around the world. Under natural field conditions, the diseases are caused by infection of soil-borne plasmodiophorid Polymyxa graminis-transmitted bymoviruses of the genus Bymovirus of the family Potyviridae. Focusing on barley and wheat, this article summarizes the achievements on taxonomy, geography and host specificity of these disease-conferring viruses, as well as the genetics of resistance in barley, wheat and wild relatives. Moreover, based on recent progress of barley and wheat genomics, germplasm resources and large-scale sequencing, the exploration and isolation of corresponding resistant genes from wheat and barley as well as relatives, no matter what a large and complicated genome is present, are becoming feasible and are discussed. Furthermore, the foreseen advances on cloning of the resistance or susceptibility-encoding genes, which will provide the possibility to explore the functional interaction between host plants and soil-borne viral pathogens, are discussed as well as the benefits for marker-assisted resistance breeding in barley and wheat.