Jonikas Lab: Engineering Photosynthesis

Research
Posted on January 11, 2017

Originally trained in aerospace engineering at MIT, Martin Jonikas has the engineer’s natural interest in understanding how machines work and how they might be improved. But instead of spending his career developing aircraft or rocket technology, Jonikas has ended up studying the photosynthetic organisms that have supported life on Planet Earth for eons, with the aim of improving their function to address some of the 21st century’s most pressing environmental concerns.

Martin JonikasAn electron microscopy image of a Chlamydomonas cell, with the pyrenoid highlighted in blue and the surrounding chloroplast colored green.}

Jonikas, who joined the Department of Molecular Biology as an assistant professor in October, began his transition to the biological sciences near the end of his undergraduate studies, when he took a required course in biology and realized that the molecular machines that operate inside cells were far more impressive than the aerospace gadgets he was already familiar with. Then, while a graduate student at UCSF studying the inner workings of budding yeast, Jonikas became interested in photosynthetic organisms such as plants, which use the energy from sunlight to convert carbon dioxide into sugar. “They’re fundamental to how life on Earth works,” Jonikas explains. “They made the atmosphere how it is today by sucking out the carbon dioxide and producing all the oxygen that we breathe. But it’s surprising how little we actually know about them. We don’t even know all of the genes that are required for photosynthesis.”

Setting up his own group at the Carnegie Institution for Science in Stanford in 2010, Jonikas decided to adapt some of the high-throughput techniques he’d been using with yeast and apply them to Chlamydomonas, a model single-celled photosynthetic alga. (Algae are thought to be responsible for nearly half of all the photosynthesis that occurs around the world). Jonikas assembled a team that generated a library of Chlamydomonas strains carrying known mutations in most of the alga’s ~17,000 genes, the first such resource in any single-celled photosynthetic organism. The project has been a resounding success, and, already, over 100 labs around the world are studying individual mutant strains from the collection.

Jonikas and his team are now using robotic systems – another early engineering interest of his – to systematically analyze the behavior of all the strains in the library and determine the localization and interactions of every Chlamydomonas protein. Together, this approach should reveal what each protein does, and determine the complete set of genes required for every cellular process, including photosynthesis.

Jonikas is particularly interested in the genes required to form a specialized carbon-fixing structure called the pyrenoid. Photosynthetic organisms have become victims of their own success in sucking out carbon dioxide from the atmosphere. Levels of the gas are now too low for many plants and algae to photosynthesize efficiently, limiting the growth of key agricultural crops. But some species have evolved carbon-concentrating mechanisms that allow them to capture carbon dioxide more efficiently. Algae such as Chlamydomonas have developed the pyrenoid, a ball-like structure containing massive amounts of the carbon dioxide-capturing enzyme Rubisco. Jonikas hopes to understand how the pyrenoid is assembled; his lab has already identified a protein that helps to glue all the Rubisco molecules together.

“We think that if we can understand how the pyrenoid works, we might be able to transfer this carbon-concentrating mechanism into crops,” Jonikas says. “That could improve their growth and reduce both water usage and the need for fertilizer. It’s early days but we’re hopeful we can help enhance global food production.”

To help the public appreciate Chlamydomonas’ enormous potential, Jonikas’ lab has collaborated with the “Song A Day” writer Jonathan Mann to create a series of YouTube videos such as Sammy the Chlamy and The Jonikas Lab Song. “We hope we can make more videos in the future,” Jonikas says. “It’s a great way to share what we’re doing in the lab.”