AAFC IWYP Aligned Call; Circadian clock editing in wheat

The overall aim of this project is to utilize advanced biotechnology, genomics, functional genomics, and breeding techniques to develop next-generation wheat germplasm that will increase the security of global wheat production and address the need for a 50% increase in genetic yield potential by 2050 (IWYP). Global warming is predicted to increase temperature and the frequency of extreme weather events, and also to alter precipitation patterns and abundance, thus changing water availability to crops. Another direct consequence is that the number of frost-free days in many regions will become comparable to what is typical of more southern regions, however the day length will remain unchanged. For this reason, alignment of photoperiodic requirements with the growing season is key to the successful integration of high yielding wheat genotypes. It is imperative that we protect wheat production by developing next-generation germplasm that is adaptable and resilient to anticipated variable climatic conditions. This project will seek to generate and deploy genetic variation in circadian clock genes with relevance to IWYP aims of increasing yield in several ways: 1. We will harness the power of circadian clock genes in controlling yield and stress responses. 2. We will optimize growth through modulation of circadian clock genes for yield increase and improved stress responses. 3. The circadian clock mutant (ccWheat) germplasm will be incorporated into wheat breeding at AAFC and elsewhere. 4. Mutational breeding tools, genome editing and methods to control recombination, will be further developed for accelerating breeding for yield and stress responses.

To date, wheat breeding has been a slow and iterative process, taking many years for new, incremental gains to be made. Climate change adds to the yield challenge and new solutions are therefore required to sustain wheat production. In line with this, advanced technologies such as genome editing, which can provide either direct or indirect avenues for accelerated trait incorporation, will be an essential component of the solutions. This is especially true since genome editing can quickly create mutations in all gene copies encoded by wheat's three subgenomes that would challenging to achieve using conventional breeding approaches. Alignment of this project with the 2018 broad challenge #6 "In collaboration with international partners, upstream trait discovery, trait development and fundamental science with the goal of increasing the genetic yield potential in wheat by 50% in the next 20 years" renders this project both timely and well-positioned. To achieve the desired outcomes, we will employ an integrative approach of accelerated evolution through genome editing and conventional breeding to modulate the circadian clock (CC) of wheat and develop variable climate resilient wheat germplasm (ccWheat) for breeders. Collectively, CC core genes are highly conserved, widely affect aspects of plant development, and have contributed to crop improvement. The fundamental role of the plant CC is to anticipate daily (sunrise/sunset) and seasonal (summer to winter) changes for the optimization of plant cellular processes with respect to external conditions.

Wheat is the world's most widely cultivated crop and contributes about 20% of the calories consumed by humanity. To meet global demand for food by 2050, staple crop yield must be increased by 50%, contrasting the current annual yield increase of 1.4%. In most countries, arable crop land areas are limited and will not expand. The impact of extreme weather events will decrease crop yield up to 50%, thus seriously affecting farm sustainability. Collectively, these forces are driving the need for novel wheat germplasm with dramatically increased yield potential under variable climatic conditions, something classical breeding tools are no longer capable of achieving in the required amount of time.

Genome editing provides a viable solution for increasing yield potential. Unfortunately, current regulations surrounding the use of genome editing technologies differ around the world. Canada, USA and other countries support its unrestricted use while the EU does not. In Canada, wheat commissions are funding genome editing research. As we cannot influence this debate very easily, our approach is to use genome editing to develop new genotypes (CRISPR mutants) and to reassemble equivalent wheat germplasm from induced mutations based on validated phenotypes. This will enable immediate utilization of novel germplasm (non-CRISPR mutants) by the wheat breeding community. Considerable advancements have the potential to be made that are of utmost relevance to wheat breeders, producers, consumers and industry, who will ultimately benefit from continued availability and affordability of wheat.

The strategic impact of research in the Henderson laboratory is via translation of meiotic recombination control into crop species, where crossovers can limit breeding. We are actively pursuing this through academic networks, including as part of a BBSRC sLola network, led by Prof. Keith Edwards (University of Bristol), where we are investigating crossovers in the hexaploid bread wheat genome, and via a Marie Curie training network comprising 11 groups across Europe. We have completed and ongoing relationships with industrial partners, including Meiogenix (BBSRC-IPA), Rijk Zwaan (Industrial Studentship), KWS and Syngenta (BBSRC iCASE). Through these networks we aim to promote translation of our understanding of recombination mechanisms into crop genomes. In the context of this project, Dr Henderson is developing methods to target recombination and increase crossovers at specific loci. These methods will be further developed in this program and applied in this project in order to enhance recombination with the circadian clock mutations generated by the Laurie group.