CAREER: Understanding non-photochemical quenching under chilling in the warm-season C4 grasses

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This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).Sensitivity to low temperatures greatly limits the distribution, establishment, and productivity of crops. The economically important grasses such as maize and sugarcane originated in a warm climate and did not develop protection against cold. In low temperatures, solar energy absorbed by leaves exceeds greatly its use for CO2 fixation, which leads to oxidative stress and subsequent photodamage, arrest of growth and eventually plant death. As a photoprotective response, the leaf switches into a ‘safety mode’ where an excess of energy can be harmlessly released. Little is known about these protective switches in warm climate grasses under cold conditions. Therefore, this project integrates physiology, biochemistry, genetics, metabolomics and field phenomics to reveal the regulation of protective mechanisms against oxidative stress under chilling and cold. Improved chilling tolerance of warm climate crops would increase their climate resilience, enable an earlier spring planting/regrowth that would extend the growing season while facilitating increased use of early season soil-moisture. The education component will train undergraduate students on the life-long skill of science communication. The research experiences will provide instrumental training to female undergraduate and graduate students, and a postdoctoral fellow. Increased participation of women in STEM will lead to a more diverse and stronger scientific workforce. The public outreach activities will aim for higher acceptance and appreciation for research innovation in feeding the world.The research goal of this proposal is to understand the non-photochemical quenching (NPQ) mechanism under chilling in C4 warm-season grasses. The study will be performed on Miscanthus, which is a close relative to maize and sugarcane while being also extremely tolerant to low temperatures. The extensive geographical distribution of Miscanthus offers unique opportunities to elucidate the underlying mechanisms of C4 photosynthesis tolerance to chilling. By spanning across levels of biological organization this project will 1) Define chilling-dependent characteristics of NPQ and their effect on plant physiology; 2) Identify how key NPQ related genes contribute to chilling light-dependent and -independent changes in NPQ characteristics; 3) Determine how NPQ is integrated at the level of the whole organism. The following education objectives are integrated with the research: 4) Develop and disseminate an undergraduate-level course to increase students’ science communication skills; 5) Engage girls in plant science via hands-on activities; and 6) Educate and engage the public on photosynthesis and its potential improvement in crop species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.