Generating broad-spectrum tolerance to ALS-inhibiting herbicides in rice by base editing

Herbicide-tolerant rice varieties generated by genome editing are highly desirable for weed control. We have used a cytosine base editor to create a series of missense mutations in the P171 and/or G628 codons of the acetolactate synthase (ALS) gene to confer herbicide tolerance in rice. The four different missense mutations in the P171 codon, P171S, P171A, P171Y and P171F, exhibited different patterns of tolerance towards five representative herbicides from five chemical families of ALS inhibitors. For example, P171S and P171A had lower levels of tolerance than P171Y and P171F to bispyribac but not to the other herbicides. Interestingly, a novel triple mutant (P171F/G628E/G629S) had the highest tolerance to all five tested herbicides. Field trials showed that both P171F and P171F/G628E/G629S could potentially be used with nicosulfuron. Our work illustrates an effective way of using base editing to generate herbicide tolerance in elite rice varieties.

Automated summary

Utilizing genome editing, various missense mutations were created in rice to confer tolerance to different herbicides, with a novel triple mutant showing high tolerance to all tested herbicides. Field trials suggested that these mutated varieties have potential practical applications in weed control.