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ARS Home » Pacific West Area » Albany, California » Plant Gene Expression Center » Research » Publications at this Location » Publication #398839

Research Project: Discovery of Plant Genetic Mechanisms Controlling Microbial Recruitment to the Root Microbiome

Location: Plant Gene Expression Center

Title: Photosynthesis in rice is increased by CRISPR/Cas9-mediated transformation of two truncated light-harvesting antenna

item Caddell, Daniel
item LANGENFELD, NOAH - Utah State University
item ZHEN, SHUYANG - Utah State University
item ECKELS, MADIGAN - Utah State University
item ZHEN, SHUYANG - Texas A&M University
item KLARAS, RACHEL - University Of California Berkeley
item MISHRA, LAXMI - University Of California Berkeley
item BUGBEE, BRUCE - Utah State University
item Coleman-Derr, Devin

Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/9/2023
Publication Date: 1/19/2023
Citation: Caddell, D.F., Langenfeld, N.J., Zhen, S., Eckels, M., Zhen, S., Klaras, R., Mishra, L., Bugbee, B., Coleman-Derr, D.A. 2023. Photosynthesis in rice is increased by CRISPR/Cas9-mediated transformation of two truncated light-harvesting antenna. Frontiers in Plant Science. 14. Article 1050483.

Interpretive Summary: In plants, pigments such as chlorophyll and carotenoids harvest light and transfer the energy towards reaction centers, where it is converted to chemical energy via photochemical charge separation, initiating photosynthesis. In full sunlight plants absorb more light than can be used towards photosynthesis. This overaccumulation enables a selective advantage in natural communities, whereby plants with large light-harvesting antenna complexes are able to outcompete neighboring plants for sunlight, which can be a major growth-limiting factor in most environments. Prevention of weed establishment in agricultural settings is often accomplished through herbicidal or management practices, such as planting in dense monocultures. In such situations, the absorption of excess photons reduces the amount of light within the canopy that is used for photosynthesis, and can negatively impact plant yields. Here we work to create new transgenic lines that have reduced chlorophyll and increased photosynthetic rate per unit photon.

Technical Abstract: Penetration of light to lower leaves limits photosynthesis in dense crop canopies. Plants compete for light partly by over-producing chlorophyll in upper leaves. The resulting high light-absorption is an effective strategy for outcompeting neighbors in mixed communities, but it prevents light transmission to lower leaves in agricultural canopies. We used a CRISPR/Cas9-mediated approach to engineer rice plants with truncated light harvesting antennae (TLA). Mutations in either of two genes involved in antennae assembly, CpSRP43 and CpSRP54, decreased chlorophyll content and light absorption and increased photosynthesis per photon absorbed (quantum yield). Additionally, we investigated a Poales-specific duplication of CpSRP54, which includes staple foods such as rice, wheat, corn, millet, and sorghum. We compared the contributions of individual TLA components by studying the growth rates of whole plants, quantum yield of photosynthesis, chlorophyll density and distribution, and phenotypic expression of CpSRP43, CpSRP54a, and its paralog, CpSRP54b. These results have significant implications for high leaf-area-index crop monocultures.