Genetic variation in rice momilactone biosynthesis

• Applicant: Professor Dr. Claude Becker
• Subject Area: Plant Genetics and Genomics ; Organismic Interactions, Chemical Ecology and Microbiomes of Plant Systems
• Term: from 2020 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 457739273

Plants usually grow in dense communities, together with plants from the same or a different species. Because resources are scarce, plants must compete with their neighbours for nutrients, space, and water. In a strategy called ‘allelopathy’, plants produce and release chemical compounds that are harmful for their neighbours. This type of biochemical interference between plants also occurs between crop plants and weeds that infest agricultural areas. It is therefore important to understand the molecular mechanisms employed during allelopathy, to develop strategies by which crops can protect themselves against invaders without harming themselves.Rice is the most important crop worldwide based on calorie supply. Every year, weed infestation of rice fields, particularly by the grassy weed Echinochloa crus-galli (cockspur grass) causes massive losses in potential production. At the same time, rice is an allelopathic crop, meaning that it has the capacity to produce and release weed-suppressive chemical compounds. The main chemicals are momilactones, of which there are two forms, A and B. While momilactone A is produced when the rice plant is under attack by fungal pathogens, momilactone B is produced as a repellent against neighbouring weeds. However, it remains unclear how the rice plants perceive and recognize their neighbours. Earlier studies have shown that different rice varieties and cultivars have different allelopathic strength, meaning that some are better in suppressing weeds than others. However, it is unclear whether this variation is related to different levels of momilactone production. Momilactone-based allelopathy can potentially be used to breed new cultivars that can naturally defend themselves against invading weeds, thus reducing the need for synthetic and potentially harmful herbicides. To apply such strategies, knowledge on the natural genetic variation that determines the allelopathic strength of different rice strains is indispensable.Here, we propose to use an existing resource of rice natural and cultivated variation, the 3000 Rice Genomes resource, to investigate the genetic components of momilactone production and its regulation. By combining metabolite analyses in hundreds of rice cultivars with genomic and quantitative genetic approaches, we aim to identify genomic loci that control the baseline production rate and the responsiveness to nearby neighbours of momilactone synthesis. Our ultimate objective is to prepare the ground for the development of sustainable, resource-friendly weed management strategies.

• DFG Programme: Research Grants
• International Connection: Japan
• Cooperation Partner: Professor Dr. Kazunori Okada