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Crop Biotech Update

Chinese Scientists' Genome-Edited Wheat to Help Control Weeds

April 17, 2019

A close relative of wheat, jointed goatgrass (Aegilops tauschii) has been worsening the problems of Chinese farmers. Mesosulfuron is the only wheat-registered foliar-applied herbicide that provides control of jointed goatgrass in China, but using it damages wheat crops. Non-transgenic wheat varieties tolerant to imidazolinone (IMI) herbicides can help solve these problems, but IMI herbicides remain in the soil and severely damage sensitive crops planted months and even years later.

Researchers at the Institute of Genetics and Developmental Biology of the Chinese Academy of Sciences (IGDB, CAS) and China Agricultural University (CAU) generated several herbicide-tolerant wheat germplasms using base editing to facilitate weed control in wheat fields. The wheat germplasms harboring herbicide tolerance mutations confer tolerance to sulfonylurea-, imidazolinone- and aryloxyphenoxy propionate-type herbicides by base editing the acetolactate synthase (ALS) and acetyl-coenzyme A carboxylase genes of commercial wheat cultivar Kenong199.

The mutations at wheat ALS P174 codon (TaALS-P174) endow tolerance to nicosulfuron, a sulfonylurea herbicide with a relatively low risk to subsequently planted crops. The mutations at both the TaALS-P174 and TaALS-G631 conferred tolerance to imazapic, an IMI herbicide, at three to five times the field-recommended rate. The researchers also obtained quizalofop-tolerant wheat by editing TaACCase-A1992. The researchers also found that base editing at TaALS-P174 endowed wheat with sufficient resistance to nicosulfuron herbicide in MS growth medium to allow selection.

For more details, read the CAS Research News.