Gene editing in wheat to improve herbicide and stress tolerance

Description of the topic

Certain genes are known to affect nutrient uptake and tolerance to abiotic stresses and herbicides. For example, down-regulation of ethylene biosynthesis (via ACC synthase) is known to improve plant performance under drought stress. Similarly, molecular modification of nitrate reductase in a single amino acid increases its half-life considerably by keeping it from being targeted for degradation. Mutant forms of acetolactate synthase (ALS) have long been known to confer upon the plant the ability to survive imidazolinone herbicides. The ALS protein possesses a dozen or so amino acids which, upon alteration to other amino acids, give plants resistance to various classes of sulfonylureas, which offers the possibility of developing wheat that is tolerant to a broad spectrum of chemical herbicides. The CRISPR-Cas system is being set up in the Biosafety Laboratory at CIMMYT to edit genes. Under this project, we will either inactivate the genes for the formation of ethylene or change specific amino acids to alter the properties of the resultant protein for nutrient use efficiency or herbicide tolerance.

Work expectations

Become familiar with wheat transformation, which has already been streamlined in the Biosafety Laboratory. Isolate protoplasts from wheat seedling leaves and use them to test various guide-RNA sequences for the gene of interest for efficacy in transient assays. Select the most efficacious gRNA for transformation in combination with Cas9 into immature embryos. Regenerate plants, analyze for gene alteration by PCR and by next generation sequencing (after adding unique adaptors and combining DNA from 384 plants into a single sample). Test the plants with edited genes for the appropriate traits. Each edited gene would potentially lead to publishing a paper in a high-profile journal

Required skills

Ph.D. in genetics, physiology, biochemistry, or a related field.