Light to Life

Plants constitute more than nine-tenths of the total biomass on Earth (~70 billion tons). Plants dominate the Earth because the can capture sunlight and convert it into chemical energy through the process of photosynthesis. This conversion of light energy by photosynthesis yields approximately 100 terawatts of power annually: six times the power consumption of human civilization! Photosynthesis supports life on the planet, from microbes to humans.

While we know the essential building blocks of the photosynthetic machinery, we understand less about the dynamics of this machinery, the diversity of photosynthetic functions among organisms, and how photosynthesis is regulated in an ever-changing environment. Furthermore, harvesting light energy can be dangerous to photosynthetic cells; captured energy has the potential to be toxic as a consequence of the formation of reactive oxygen. Plants have evolved a suite of mechanisms to mitigate such damage. These include sophisticated light, energy and redox status signaling networks that allow plants to adjust photosynthetic function. Plants respond to these signals by modulating the structure and interactions of the core photosynthetic complexes, deploying energy-dissipating mechanisms, and altering both whole plant and cellular architecture to optimize light capture and minimize photodamage.

Today, Arthur Grossman’s lab is at the forefront of research on the regulation of photosynthesis using biochemical, physiological, genetic and genomic tools in cyanobacteria and the green alga Chlamydomonas. He was awarded the Gilbert Morgan Smith Medal in 2009 by the National Academy of Sciences for his innovative use of algal systems.

Winslow Briggs’ lab has long been a world leader in discovering the mechanisms by which plants sense and respond to light. Winslow’s lab identified the blue light receptors that drive phototropism, the direction of growth towards light, and chloroplast positioning. This discovery was recognized by the International Prize in Biology in 2009.

Devaki Bhaya’s lab studies phototaxis in photosynthetic bacteria, and has identified the photoreceptor and novel components of this complex pathway. She also studies environmental acclimation in communities of photosynthetic microbes in the extreme environment of hot springs.

M. Kathryn Barton’s lab identify the molecular mechanisms that shape the plant body, especially the production and shape of leaves, a central issue in optimizing light capture by the plant.

Zhi-Yong Wang’s lab studies how photoreceptors and hormones act together to control cell elongation and seedling morphogenesis according to light and shade condition.