By Chloe Hinson, Masters in Plant Sciences & Plant Pathology
Montana is experiencing higher summer temperatures and there is a 3-5% yield loss for each 1.5°F increase above 60°F during the spring wheat growing season. Heat stress slows wheat head growth during the booting stage and damages flower development, resulting in shorter heads with fewer flowers that produce smaller and fewer seeds. My research shows that a natural plant hormone, brassinosteroid (BR), can help wheat heads maintain their length and flower number, and improve seed size development during heat stress. I have been investigating the ways that BR is helping these yield components so that we can understand the genetics behind these traits.
One way that heat stress damages cells is through oxidation, which is when oxygen containing molecules damage proteins or other cellular parts of the plants. Plants usually stop oxidation using antioxidants, like vitamins or special enzyme proteins, and in some broadleaf crops BR increases the activity of antioxidants. I have explored how BR affects antioxidants in Montana spring wheat and how BR could help control oxidation during heat stress to improve yield components.
I found that blocking the natural BR in spring wheat slowed down antioxidant activity, increased oxidation, and this was related with smaller seed production under heat stress. I also saw that when we added BR, antioxidant activity responded differently to heat stress and this corresponded to better flower protection. We can use these findings to inform wheat breeding with better antioxidant activity, protect the size and flowers of stressed heads, and produce more seeds. My research helps us understand the ways in which wheat can overcome heat stress, so that we can improve production across the state.