BOOSTER Gene: Unlocking New Potential in Photosynthesis and Crop Productivity

By Dr. Chinta SidharthanReviewed by Lily Ramsey, LLMDec 17 2024

Understanding how plants optimize photosynthesis under varying environmental conditions is crucial for improving crop productivity. Photosynthesis, the process by which plants convert light energy into chemical energy, often encounters inefficiencies due to fluctuating light conditions and limitations in key enzymes.

In a recent study published in Developmental Cell, researchers from the United States investigated the activity of the naturally occurring gene BOOSTER, found in poplar trees. This gene enhances photosynthesis and plant productivity.

By examining genetic variations and employing transgenic methods in poplars and Arabidopsis thaliana, the researchers demonstrated that BOOSTER improves photosynthetic efficiency under steady and dynamic light. These findings offer promising avenues for boosting agricultural yield across diverse plant species.

​​​​​​​Study: An orphan gene BOOSTER enhances photosynthetic efficiency and plant productivity. Image Credit: chayanuphol/Shutterstock.com

Background

Photosynthesis is essential for plant growth, yet environmental factors, such as fluctuating light intensity, often constrain its efficiency. When light transitions rapidly between sun and shade, plants must adjust their photosynthetic processes to prevent energy loss or photodamage.

Non-photochemical quenching (NPQ) mechanisms dissipate excess energy to protect photosystems, but their slow relaxation during light transitions limits the carbon gain.

Moreover, the primary enzyme of photosynthesis, Rubisco, is susceptible to oxygen inhibition, further reducing efficiency.

Advances in genetic engineering have targeted photosynthetic optimization, including modifying light-response pathways and Rubisco activity, but these approaches yield inconsistent results across plant species.

Our understanding of the genetic factors underlying photosynthetic regulation in natural settings remains incomplete.

However, recent studies have suggested that chimeric genes derived from organelle-to-nucleus deoxyribonucleic acid (DNA) transfers could play a role in adapting to environmental variability.

The Current Study

Here, the researchers employed genome-wide association studies on a diverse panel of 743 Populus trichocarpa (poplar species) samples to identify genetic variants influencing photosynthetic traits, especially NPQ dynamics under fluctuating light.

Among the identified candidates, the gene BOOSTER, comprising a chimeric structure with sequences of endophytic and plastid origin, was strongly associated with improved photosynthetic performance.

The researchers conducted ribonucleic acid (RNA) sequencing and analysis of high- and low-expression genotypes to confirm the functional role of BOOSTER.

To further validate BOOSTER’s effects, the study used transgenic Populus tremula × P. alba and generated Arabidopsis thaliana lines that overexpressed BOOSTER. Photosynthetic efficiency and growth parameters were assessed under controlled greenhouse conditions and fluctuating light regimes.

These experiments included measurements of NPQ induction and relaxation, quantum efficiencies of carbon dioxide (CO₂) assimilation, and Rubisco activity. Additionally, high-throughput phenotyping and field trials were conducted to evaluate plant height, biomass, and other growth traits.

By integrating genetic, physiological, and molecular approaches, the study explored the enhancement of photosynthetic efficiency and biomass production through BOOSTER under both steady and dynamic light conditions.

The researchers aimed to provide insights into the genetic mechanisms underpinning photosynthetic adaptation and offer strategies for agricultural improvement.

Major Findings

The results suggested that BOOSTER significantly enhances photosynthetic efficiency and plant growth. The genotypes of Populus trichocarpa that had higher expression of BOOSTER exhibited faster NPQ relaxation and improved light-use efficiency compared to low-expression genotypes.

Moreover, transgenic plants overexpressing BOOSTER showed substantial improvements in photosynthesis and biomass under greenhouse and field conditions.

In poplars, BOOSTER expression correlated with up to a 35% increase in photosynthetic rates and an 88% increase in stem biomass.

Additionally, transgenic Arabidopsis lines demonstrated enhanced efficiency of CO₂ assimilation and electron transport under fluctuating light, with biomass and seed production improvements of up to 200% and 50%, respectively.

Rubisco abundance and activity were also significantly higher in BOOSTER-expressing plants, contributing to improved carbon assimilation.

Furthermore, field trials involving poplars revealed consistent increases in plant height, crown area, and stem volume across multiple locations and growth stages. The high-expression genotypes also displayed better adaptation to variable light conditions, maintaining efficient energy dissipation and carbon gain.

Complementation experiments using plants with mutations in sigma factor-6, a nuclear-encoded protein that plays a role in plant greening and plastid development, showed that BOOSTER restored photosynthetic efficiency independently of traditional sigma factor pathways, supporting its role in anterograde or forward signaling between the nucleus and plastid.

Additionally, molecular localization studies revealed that the BOOSTER protein is distributed in the nucleus, plastids, and endoplasmic reticulum, suggesting its involvement in inter-organellar signaling.

Advanced protein modeling and structure-function analysis confirmed the gene’s unique features, including a helix-extended-helix motif that is crucial for its activity.

Conclusions

Overall, the study highlighted the potential of BOOSTER as a transformative genetic tool for enhancing photosynthesis and plant productivity.

By improving light-response mechanisms and optimizing metabolic efficiency, BOOSTER was found to increase growth and biomass in both poplars and Arabidopsis significantly.

The researchers believe that the broad applicability of BOOSTER across plant species and environmental conditions presents a promising strategy for meeting global agricultural demands, particularly under the challenges of climate variability and resource limitations.