Herbicide tolerance-assisted multiplex targeted nucleotide substitution in rice

Area of Science:

• Plant biochemistry
• Molecular genetics
• Agricultural science

Background:

• Acetolactate synthase (ALS) is crucial for branched-chain amino acid synthesis in plants and is a herbicide target.
• While ALS mutations conferring herbicide resistance are known, their specific impact on rice and tolerance to Imazamox (IMZ) remained unclear.

Purpose of the Study:

• To evaluate the effect of Imazamox (IMZ) on rice growth and identify ALS mutations conferring IMZ tolerance.
• To demonstrate ALS-assisted multiplex targeted base editing in rice.

Main Methods:

• Assessing the impact of IMZ on rice calli and seedlings in vitro.
• Identifying and confirming the ALS A96V mutation for enhanced IMZ tolerance.
• Implementing multiplex targeted base editing using the CRISPR/Cas9-cytidine deaminase fusion system (Target-AID).

Main Results:

• The ALS A96V mutation was confirmed to confer Imazamox tolerance in rice calli.
• The study successfully demonstrated ALS-assisted multiplex targeted base editing in rice.

Conclusions:

• The ALS A96V mutation is a key factor in conferring Imazamox tolerance in rice.
• ALS-assisted multiplex targeted base editing offers a promising approach for crop improvement in rice.