New Study Shows that Decreasing Antenna Size of Photosystem can Improve Canopy Photosynthetic Efficiency

Improving canopy photosynthesis is a major viable approach to drastically increase crop yields. However, canopy photosynthesis is determined not only by leaf photosynthetic properties, which are further determined by a complex array of energy conversion, electron transfer, CO2 fixation processes, but also by highly heterogeneous canopy microclimates, such as light, temperature etc., inside the canopy. As a result, identifying new options to improve canopy light use efficiency has become a major task for plant biologists and crop breeders. 

Recently, a study led by Dr. ZHU Xinguang at Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, describes an in silico approach to rapidly identify new potential options to modify plants for improved canopy photosynthesis.

This new in silico approach relies on the success of developing a dynamic systems model of canopy photosynthesis, which effectively integrates leaf photosynthetic processes, leaf shape and canopy architecture information; it can be used to quantitatively study canopy photosynthetic efficiency and examine the consequences of modifying any properties related to photosynthesis, leaf shape, or canopy architecture on canopy photosynthetic efficiency, and hence can be applied to design crops for optimized canopy photosynthesis.

With this model, researchers demonstrated that decreasing antenna size of photosystem can increase canopy photosynthetic efficiency and nitrogen use efficiency. Decreasing antenna is shown to be able to improve canopy photosynthesis through two mechanisms, i.e. decreasing the loss of energy through heat and increasing the light availability for leaves in the bottom layers of a canopy.

This new finding cast major doubts on the current dogma held in major crop breeders, i.e. greener leaves are equivalent to higher photosynthesis and hence should be selected during breeding. In nature, leaves tend to evolve greater antenna, with the possible driving forces including capturing more nitrogen inside leaves, i.e. leaving less for their competitors, and shading other neighboring competitors. The research under process is focusing on identifying approaches to manipulate antenna size of photosystem to boost crop canopy photosynthesis for greater yields.

This work, entitled "The impact of modifying photosystem antenna size on canopy photosynthetic efficiency-Development of a new canopy photosynthesis model scaling from metabolism to canopy level processes ", was published in Plant, Cell & Environment. It is funded by the strategic leading project, Ministry of Science and Technology of China, Bill and Melinda Gates Foundation, China National Science Foundation and State Key Laboratory of Hybrid Rice.

Article website:
http://onlinelibrary.wiley.com/doi/10.1111/pce.13041/full

Diagram showing a multi-scale dynamic systems model of canopy photosynthesis

Author contact:
ZHU Xinguang, Professor and principal investigator
Institute of Plant Physiology and Ecology (SIPPE)
Chinese Academy of Sciences (CAS)
300 Fenglin Road, Shanghai 200032, China
Phone: (86) 21-54924163
Email: zhuxinguang@picb.ac.cn