No abstract

No abstract

Brachypodium distachyon has been proposed as a model plant for agriculturally important cereal crops such as wheat and barley. Seed coat colour change from brown-red to yellow was observed in a mutant line (142-3) of B. distachyon, which was induced by chronic gamma radiation. In addition, dwarf phenotypes were observed in each of the lines 142-3, 421-2, and 1376-1. To identify causal mutations for the seed coat colour change, the three mutant lines and the wild type were subjected to whole-genome re-sequencing. After removing natural variations, 906, 1057, and 978 DNA polymorphisms were detected in 142-3, 421-2, and 1376-1, respectively. A total of 13 high-risk DNA polymorphisms were identified in mutant 142-3. Based on a comparison with DNA polymorphisms in 421-2 and 1376-1, candidate causal mutations for the seed coat colour change in 142-3 were selected. In the two independent Arabidopsis thaliana lines carrying T-DNA insertions in the AtCHI, seed colour change was observed. We propose a frameshift mutation in BdCHI1 as a causal mutation responsible for seed colour change in 142-3. The DNA polymorphism information for these mutant lines can be utilized for functional genomics in B. distachyon and cereal crops.

No abstract

Phytophthora crown rot (PhCR) caused by Phytophthora cactorum is one of the most damaging soilborne diseases of strawberry in the United States and worldwide. Limitations on fumigants such as methyl bromide have led to deterioration in the control of P. cactorum in recent years. The development of resistant varieties is a critical component of the strategy for combatting this soilborne disease. Here, we review the biology of the pathogen, molecular mechanisms of infection, and management of PhCR in strawberry. Recent genomics advances in octoploid strawberry breeding have been able to gain a deeper insight into the genetic architecture of resistance to PhCR and identified the genetic resistance sources for the improvement of strawberry varieties against the pathogen. Quantitative trait loci (QTL) associated with PhCR resistance have been identified and introgressed for breeding of PhCR resistance in cultivated octoploid strawberry (F. × ananassa). Further characterizing candidate genes and mechanisms of resistance could facilitate incorporating the resistance genes into commercial varieties through genomics-assisted breeding, respectively. In this review, we address important recent advances and progress for genomics-assisted breeding for the resistance to PhCR and the potential use of CRISPR gene editing in cultivated strawberry.