SAFERGUARDING SONORA'S WHEAT FROM CLIMATE CHANGE

Sonora contributes 45% of the total wheat production in Mexico, however this is becoming increasingly compromised by high temperature and drought, which are an increasing problem in Sonora and globally due to climate change. There is therefore a growing urgency to "safeguard" Sonora's wheat from heat and drought stress.
Within this project, a unique wheat panel will be assembled representing the most tolerant wheat genotypes and varieties currently known, globally. This Heat and Drought panel will be evaluated and analysed under field conditions in Sonora to select the best-performers and these will be analysed in detail at the molecular and physiological level to unravel the tolerance mechanisms and identify the underlying genes. Most molecular-physiological studies on stress responses have been conducted using intolerant reference genotypes, mainly because genetic resources are available, and in addition, plants are often grown under laboratory conditions. We therefore presently have very little information on tolerant-specific stress responses in crops, and even less in wheat. This project will therefore generate a first-of-its-kind comprehensive study on "true" tolerance mechanisms in wheat and this will have large implications for the research community and for breeding programs.
One of the drought responsive pathways that will be analysed in detail within this project is related to the role of sugars in stress tolerance and the regulation of sugar allocation to seeds via trehalose-6-phosphate (T6P). It has already been proven that external application of T6P can enhance drought tolerance and the genes within this pathway are therefore prime targets of this project. One of these genes (TPS) is of particular interest and has already been subjected to gene editing using CRIPR-Cas9 technology. There are currently very few studies that go beyond the proof-of-concept that this technology works in wheat and this project will therefore pioneer this breakthrough technology for applications in wheat improvement, providing a land-mark study.
Sharing expertise and joining forces, this project will be conducted in collaboration between CIAD in Sonora and Rothamsted Research (RRes) in the UK, building on the broad expertise and pre-existing collaborations of the PIs, their established partnership with CIMMYT and ICARDA, as well as integration with ongoing wheat research programs, such as "Designing Future Wheat" (DFW) in the UK, "International Wheat Yield Partnership" (IWYP) or "Wheat for a Hot and Dry Climate", an Australian Industrial Transformation Research Hub.
The data generated within this project will not only greatly enhance our understanding of tolerance mechanisms in wheat, but, via this existing network, will inform breeders about which traits and genes to target and select for. Through provision of validated heat and drought tolerant germplasm, detailed information on tolerance mechanisms for better targeted phenotyping and selection, as well as molecular markers for selection of superior tolerance-related genes, this project will enable tolerance breeding whilst doing excellent science.

Wheat is one of the top three food security crops providing a fifth of the world's calories with the widest distribution of any major crop; it is grown at a range of latitudes in Mexico, North and South America and most other regions in world. In most environments, drought is the major factor that limits crop yields accounting for millions of tonnes of grain loss annually. This is further aggravated by heat stress, which is becoming more frequent due to climate change. Both, heat and drought stress are particularly prevalent in Mexico. The outputs of this project - tolerant germplasm, genes and insight into mechanisms that increase wheat yields in Mexico and similar environments - will therefore have wide ranging and significant impact in Mexican and global agriculture.

In Mexico, wheat production and the area planted to wheat is steadily declining, due to lack of irrigation water in combination with severe heat events. In 2018, the wheat area was reduced by 23% compared with 2017, corresponding to a 20% reduction in wheat production (1). As a consequence, after wheat imports were decreasing by 10% between 2000 and 2010, Mexico's wheat import has since increased by 180% to about 5.5 MMt in 2018 (2). In light of the vulnerability of the global commodity market and fluctuation in wheat prices, securing wheat production in Mexico is important since it will reduce dependence on wheat imports, which will have a direct positive impact on food prices and food stability in Mexico, both factors important for economic growth.

Assuming a 10% yield loss due to heat and drought stress, this would amount to 0.13 MMt corresponding to a value of MXN $504 million (£20.2M) with the current world market price. If this project is successful to reduce these yield losses by only 10% (worth MXN $50-69 M) it would represent a return on investment (ROI) for Mexico of 10-14 times the initial investment of $5M MXN for the Mexican component of this project each year (see ODA statement for details).
Reducing the risk of crop failure caused by heat and drought will thus directly secure income of farming house-holds and farm employees, but will also benefit the entire wheat-value chain, consumers and society as a whole.

The knowledge on how this can be achieved and the genetic resources compiled and validated within this project will benefit wheat breeding programs and will significantly impact the scientific community (see Academic Beneficiaries for details). The latter is expected because this project will use tolerant wheat genotypes to dissect the molecular-physiological tolerance mechanisms, as opposed to using reference genotypes that are stress intolerant but commonly used in research.

The proposed project will build lasting research capacity in Mexico and because it is embedded in a global wheat research community including commercial partners, this project will provide ample training and networking opportunities for the Mexican partners and PhD student. Building on this, new collaborative projects can be developed to further enhance research capacity and impact.
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(1) United States Department of Agriculture Foreign Agricultural Service Circular Series WAP 6-18 June 2018
(2) https://www.indexmundi.com/agriculture/?country=mx&commodity=wheat&graph=imports