Ph.D. Program in Plant Molecular Biology

Friday Seminar by Dr. Zainul Abdeen Khan

IDG Lab/ Friday/October 26, 2018/ 3.30 pm/ CRISPR/Cas(-Mediated Resistance Against Plant Viruses
Category: Research

CRISPR/Cas9-Mediated Resistance Against Plant Viruses

Plant viruses infect many economically important crops, including wheat, cotton, maize, cassava and other vegetables. These viruses pose a serious threat to agriculture worldwide, as decreases in cropland area per capita may cause production to fall short of that required to feed the increasing world population. Under these circumstances, conventional strategies can fail to control rapidly evolving and emerging plant viruses. Genome-engineering strategies have recently emerged as promising tools to introduce desirable traits in many eukaryotic species, including plants. Recent studies have used CRISPR/Cas9 (clustered regularly interspaced palindromic repeats/CRISPR-associated 9) to engineer virus resistance in plants, either by directly targeting and cleaving the viral genome, or by modifying the host plant genome to introduce viral immunity. Transient assays using Bean yellow dwarf virus (BeYDV) and Beet severe curly top virus (BSCTV)-based replicons revealed that CRISPR–Cas9 reagents introduced mutations within the viral genome and reduced virus copy number. Transgenic Nicotiana benthamiana and Arabidopsis plants expressing CRISPR–Cas9 reagents and challenged with geminiviruses (BeYDV and BSCTV, respectively) had reduced virus load and symptoms. CRISPR/Cas9 technology has been utilized to introduce sequence-specific deleterious point mutations at the eukaryotic translation initiation factor (eIF(iso)4E) locus in Arabidopsis thaliana to successfully engineer complete resistance to Turnip mosaic virus, a major pathogen in field-grown vegetable crops. By segregating the induced mutation from the CRISPR/Cas9 transgene, the authors outline a framework for the production of heritable, homozygous mutations in the transgene-free T2 generation in self-pollinating species. Analysis of dry weights and flowering times for four independent T3 lines revealed no differences from wild-type plants under standard growth conditions, suggesting that homozygous mutations in eIF(iso)4E do not affect plant vigour. Thus, the established CRISPR/Cas9 technology provides a new approach for the generation of plant virus resistance in important crops.

Zainul Abdeen Khan, Ph.D.