AWC - Funded Research

Upcycling a defeated disease resistance R gene of wheat

AWC Contribution: $135,000

Summary:  

Given the limited number of effective stripe rust resistance genes available and the ability of the stripe rust pathogen to evolve and defeat current resistance genes, the future looks grim for deployment of effective and sustainable resistance in wheat against stripe rust. Modifying defeated stripe rust resistance genes to make them effective again will provide effective and sustainable stripe rust genetic resistance that will remain available against this ever evolving pathogen.


Objectives:

The overall objective of the project is to demonstrate the possibility to reuse a defeated R gene after sequence modification to protect wheat against stripe rust in Canadian germplasm.

  1. Develop different Yr10 sequences with modified CC domains and LRR domains.
  2. Identify mutagenized sequences of Yr10 with a new spectrum of resistance.

 

Benefit to industry:

Currently, wheat growers are using fungicides to protect wheat yield against losses due to Pst. Although the price is around $25/acre plus application cost per treatment, this has a financial impact when large acres are taken in consideration. Furthermore, there is an environmental impact of fungicides on both plant and soil microbiomes that can have a negative impact on plant productivity. Additionally, in Europe where fungicides have been used routinely for a much longer period of time to mitigate stripe rust impact, resistance has emerged and now, only two types of chemistry are functional to mitigate the development of stripe rust. This reality is more alarming in view of the recent publication that somatic recombination is very active in the asexual life cycle of Pst. It is during this cycle when wheat is infected by Pst during multiple rounds, thus greatly increasing the probability that in North America, Pst isolates with fungicide resistance will develop. The question remains when? The Canadian wheat industry needs to be ready when this happens. As options for introduction of effective R genes against Pst are limited, an alternative source of R genes will be needed. This is where this investigation of recycling known eroded R genes by rendering them effective again is very attractive. This is a proof of concept study in Canadian germplasm as prior successful studies have been reported in rice and wheat. The information gathered during this project will be translated to the wheat breeder colleagues at our Centre and at other wheat breeding centers using the usual dissemination tools including presentations at field days, growers and scientific meetings and publications. The results will be incorporated to protect wheat against the Pst through the process of genome editing. Recent reports from USA are suggesting that genome edited plants are not going to be considered transgenic plants. Genome edited events in canola and corn have been approved by CFIA last year in Canada. Once we have demonstrated the mutagenesis of Yr10 to modify its avirulence profile against Pst, the genome editing technology will enable modification of Yr10 in one elite wheat line. Different versions of Yr10 in different wheat elite lines could be then crossed together to obtained wheat lines with multiple different and effective Yr10 variants toward a stable resistance against Pst.


Bio:

Dr. André Laroche is a Research Scientist with Agriculture and Agri-Food Canada‎. He has more than 35 years of research experience in the areas of plant molecular biology and molecular phytopathology. His research interest widely range from cereal functional genomics of biotic (snow mould resistance, smut and bunt, stripe and leaf rust) and abiotic stress tolerance (winter hardiness, drought), to biorefinery, methodology development, DNA marker assisted selection, lipid metabolism and gene modification. His current scientific interests involve the characterization of the stripe rust pathogen isolates and their interactions with wheat and identification of novel rust resistance genes. He also edits genes to improve their response against pathogens and to variable climatic conditions. He is also affiliated as Adjunct Professor with Department of Biological Sciences, University of Lethbridge.