Photosynthesis is the process underlying all plant growth. Scientists aim to boost photosynthesis to meet the increasing global demand for food by engineering its key enzyme Rubisco. Now, researchers at the Max Planck Institute of Biochemistry have succeeded in producing functional plant Rubisco in a bacterium. This allows genetic engineering of the enzyme. The study could one day lead to better crop yields and plant varieties with increased water-use efficiencies or enhanced temperature resistance. The results were published in Science.
The world's population is predicted to exceed 9 billion in 2050. With more mouths to feed, there is a pressing need for improved food output. To meet the global demand for food, scientists aim to increase the efficiency of photosynthesis and therefore crop productivity.
Photosynthesis is the fundamental biological process that underlies all plant growth and supports life on Earth. Plants use the energy of sunlight to convert carbon dioxide (CO2) and water to sugar and oxygen (O2). The critical enzyme in this process is Rubisco. Rubisco catalyses the first step in carbohydrate production in plants, the fixation of CO2 from the atmosphere.
In doing so, plants utilize CO2 to build biomass and produce the required energy for growth. However, Rubisco is an inefficient enzyme as it captures CO2 slowly. Competing reactions with O2 further impair Rubisco’s catalytic efficiency. For these reasons, Rubisco often limits the rate of photosynthesis and ultimately plant growth, making Rubisco a hot target for genetic engineering.
Engineering of plant Rubisco, and photosynthesis, would be enhanced by functional expression of the enzyme in alternative hosts. So far, however, scientists failed to produce an enzymatically active form of plant Rubisco in a bacterial host – a goal that has been sought after for many decades. A team led by Manajit Hayer-Hartl, head of the research group “Chaperonin-assisted Protein Folding”, has now identified the requirements for expressing and assembling plant Rubisco in a bacterium. Their findings are expected to greatly accelerate efforts to improve photosynthesis through Rubisco engineering.
The Rubisco assembly line
The Rubisco enzyme consists of eight large and eight small subunits. Protein folding of the large subunits is assisted by specific chaperonins, macromolecular folding cages, in which the newly synthesized proteins can assume their proper functional conformation. After folding, multiple additional helper proteins (chaperones) assist in the proper assembly of the subunits into the large enzyme complex.
The researchers generated functional plant Rubisco in a bacterial host by simultaneously expressing plant chaperones and Rubisco in the same cells. This not only enables the scientists to understand the complex assembly pathway of Rubisco, but to modify the Rubisco gene in order to improve Rubisco’s properties. Once they have obtained a Rubisco variant with a desired trait, they can insert the modified gene back into the plant cells. This is a key-step towards improving photosynthesis through Rubisco engineering. “The bacterial expression system resembles an assembly line for cars. Whereas previously every optimized variant of Rubisco had to be painstakingly expressed in a transgenic plant, which takes a year or more to generate - like building a car by hand - we can now make hundreds or thousands of Rubisco variants in days or weeks. It is like building cars in an automated assembly line”, explains Hayer-Hartl.
Superior Rubisco variants
Genetic engineering facilitates efforts to generate Rubisco variants with improved functional properties. This might not only lead to the much-needed increase in crop yields, but also plant varieties with increased water-use efficiencies or enhanced temperature resistance - properties that are of special importance in the light of global warming and increasing water scarcity.
Aigner H*, Wilson RH*, Bracher A, Calisse L, Bhat JY, Hartl FU, Hayer-Hartl M. Plant Rubisco assembly in E. coli with five chloroplast chaperones including BSD2. Science, Dezember 2017. *These authors contributed equally to this work.
About Manajit Hayer-Hartl
Manajit Hayer-Hartl received her Bachelor of Science degree at the University of Stirling, Scotland, UK, where she afterwards gained her PhD. Her interest in structural and cellular biology motivated her to several postdoctoral fellowships at renowned research institutions, among them the Louis Pasteur Institute in Strasbourg, France and the Sloan-Kettering Institute in New York, USA. Hayer- Hartl joined the Max Planck Institute of Biochemistry in 1997 as group leader in the department “Cellular Biochemistry”. Since 2006, she is head of the research group “Chaperonin-assisted Protein Folding”. Her research focuses on chaperones and how these molecular machines assist in proper protein folding and assembly. Hayer-Hartl became EMBO Member in 2016 and was awarded the Dorothy Crowfoot Hodgkin Award in 2017.
About the Max Planck Institute of Biochemistry
The Max Planck Institute of Biochemistry (MPIB) belongs to the Max Planck Society, an independent, non-profit research organization dedicated to top level basic research. As one of the largest Institutes of the Max Planck Society, 850 employees from 45 nations work here in the field of life sciences. In currently eight departments and about 25 research groups, the scientists contribute to the newest findings in the areas of biochemistry, cell biology, structural biology, biophysics and molecular science. The MPIB in Munich-Martinsried is part of the local life-science-campus where two Max Planck Institutes, a Helmholtz Center, the Gene-Center, several bio-medical faculties of two Munich universities and several biotech-companies are located in close proximity. http://biochem.mpg.de
Dr. Manajit Hayer-Hartl
Department of Cellular Biochemistry
Max Planck Institute of Biochemistry
Am Klopferspitz 18
Dr. Christiane Menzfeld
Max-Planck-Institut für Biochemie
Am Klopferspitz 18
Tel. +49 89 8578-2824
Dr. Christiane Menzfeld | Max-Planck-Institut für Biochemie
Cereals use chemical defenses in a multifunctional manner against different herbivores
06.12.2018 | Max-Planck-Institut für chemische Ökologie
Can rice filter water from ag fields?
05.12.2018 | American Society of Agronomy
The more objects we make "smart," from watches to entire buildings, the greater the need for these devices to store and retrieve massive amounts of data quickly without consuming too much power.
Millions of new memory cells could be part of a computer chip and provide that speed and energy savings, thanks to the discovery of a previously unobserved...
What if, instead of turning up the thermostat, you could warm up with high-tech, flexible patches sewn into your clothes - while significantly reducing your...
A widely used diabetes medication combined with an antihypertensive drug specifically inhibits tumor growth – this was discovered by researchers from the University of Basel’s Biozentrum two years ago. In a follow-up study, recently published in “Cell Reports”, the scientists report that this drug cocktail induces cancer cell death by switching off their energy supply.
The widely used anti-diabetes drug metformin not only reduces blood sugar but also has an anti-cancer effect. However, the metformin dose commonly used in the...
A research team from the University of Zurich has developed a new drone that can retract its propeller arms in flight and make itself small to fit through narrow gaps and holes. This is particularly useful when searching for victims of natural disasters.
Inspecting a damaged building after an earthquake or during a fire is exactly the kind of job that human rescuers would like drones to do for them. A flying...
Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...
12.12.2018 | Event News
10.12.2018 | Event News
06.12.2018 | Event News
14.12.2018 | Power and Electrical Engineering
14.12.2018 | Physics and Astronomy
14.12.2018 | Physics and Astronomy