A team of scientists from the Center for Advanced Bioenergy and Bioproducts Innovation at the University of Illinois Urbana-Champaign and the Center for Bioenergy Innovation at Oak Ridge National Laboratory identified a gene in poplar trees that enhances photosynthesis and can boost tree height. 

Chloroplasts are the principal cell structures that house the photosynthetic apparatus converting light energy into the chemical energy that fuels plant growth. Specifically, the Rubisco protein captures carbon dioxide from the atmosphere. Scientists have for years been working on ways to boost the amount of Rubisco in plants for greater crop yield and absorption of atmospheric CO₂.

“Historically, a lot of studies have focused on steady-state photosynthesis where every condition is kept constant. However, this is not representative of the field environment in which light can vary all the time,” said Steven Burgess (CABBI/GEGC), an assistant professor of integrative biology. “Over the last few years, these dynamic processes have been considered to be more important and are not well understood.” 

In the new study, the researchers focused on poplar since it is a fast-growing crop and a leading candidate for making biofuels and bioproducts. They sampled ~1,000 trees in outdoor research plots and analyzed their physical characteristics and genetic makeup to perform a genome-wide association study. The team used the GWAS population to look for candidate genes that had been linked to photosynthetic quenching, a process that regulates how quickly plants adjust between sun and shade and dissipate excess energy from too much sun to avoid damage. 

One of the genes, which the researchers named BOOSTER, was unusual because it is unique to poplar and although it is in the nuclear genome contains a sequence which originated from the chloroplast. 

The team discovered that this gene was able to increase the Rubisco content and subsequent photosynthetic activity, resulting in taller polar plants when grown in greenhouse conditions. In field conditions, scientists found that genotypes with higher expression of BOOSTER were up to 37% taller, increasing biomass per plant. The team also inserted BOOSTER in a different plant, Arabidopsis, or thale cress, resulting in an increase in biomass and seed production. This finding indicates the wider applicability of BOOSTER to potentially trigger higher yields in other plants.

“it is an exciting first step, although these are small-scale experiments, and there is a lot of work to be done, if we can reproduce the results on a large scale, this gene has the potential to increase biomass production in crops,” Burgess said. 

Next steps in the research could encompass testing in other bioenergy and food plants, with researchers recording plant productivity in varying growing conditions to analyze long-term success. They will also be investigating the other genes that were identified in the GWAS study that could contribute to crop improvement. 

The study “An orphan gene BOOSTER enhances photosynthetic efficiency and plant productivity” was published in Developmental Cell and can be found at https://doi.org/10.1016/j.devcel.2024.11.002. The research was supported by CBI and CABBI, both sponsored by the DOE Office of Science Biological and Environmental Research Program.