This week the royal couple of science journals have turned the spotlight on CRISPR’s potential for agriculture. “Genome editors take on crops” and “CRISPR, microbes and more are joining the war against crop killers” are the titles respectively chosen by Science and Nature. The first one is a perspective by Armin Scheben and David Edwards from the University of Western Australia. “Improved crops are urgently needed to meet growing demand for food and address changing climatic conditions”, they write. The global population is expected to rise from 7.3 to 9.7 billion by 2050 and a global increase in crop production of 100 to 110% from 2005 levels will be required. Traditional plant breeding can take more than 10 years to develop an improved variety. In comparison genome editing offers substantial advantages: low cost, ease of use, lack of transgenes permanently introduced into crop germplasm, and the high level of multiplexing (editing of multiple targets). The latter allows editing of gene networks to improve complex traits such as drought resistance and yield. Multiplexing is particularly useful in polyploid crops, such as wheat.
Engineering crops to resist disease has been tricky in the past because, if the resistance gene gets too active it can damage the plant, as Brooke Borel explains in Nature. CRISPR can now make the difference, by precisely controlling the insertion site and the level of gene expression. Different labs are already using the technique to develop rice resistant to bacterial leaf streak and blight, wine grapes resistant to downy mildew, tomatoes resistant to several Pseudomonas and Xanthomonas, and powdery-mildew-resistant wheat