Plant pathogens severely affect agricultural productivity. Sustaining efficient productivity is essential for maintaining long-term food security. Much research is aimed toward finding novel resistance genes and generating crops with improved disease resistance. A majority of the disease resistance genes are dominant and encode a class of proteins with similar structural domains. The Bs5 gene has an unknown function, encodes a protein with an atypical structure compared to known resistance proteins, and is conserved among crop species. In pepper, a recessive allele (bs5) confers disease resistance against Xanthomonas euvesicatoria, which causes bacterial spot of pepper and tomato. Bacterial spot disease occurs globally and has caused major productivity losses in commercial crops.
Deploying the bs5 allele in tomato cultivars has the potential to confer disease resistance against bacterial spot in this crop as well. Pepper and tomato are not sexually compatible, so classical plant breeding strategies cannot be employed to establish bs5 resistance. Our objective is to establish bs5 resistance in tomatoes using the CRISPR-Cas9 genome editing system. We are also studying the molecular basis for bs5 resistance at the transcriptomic and proteomic levels. Investigating bs5 resistance will bolster deployment of bs5 in commercial crops and advance our understanding of monogenic resistance genes.