The Brandizzi Lab has won a 3-year National Science Foundation grant towards studying environmental stress effects in corn. The award will fund a collaboration between Iowa State University, The University of North Carolina, and MSU-DOE Plant Research Laboratory (PRL) for an amount of $3.5 million, approximately $700,000 of which will go to the PRL. The PI is Dr. Stephen Howell from Iowa State University, and Dr. Federica Brandizzi will be one of three co-PIs. (For information on graduate and undergraduate positions, go to the end.)

Plant stress is one of the major limitations currently preventing crops from achieving their yield potential. Stresses such as drought, extreme temperatures, and high salt content result in some of the greatest crop losses worldwide, estimated at billions of dollars.

Corn in particular is of interest due to its ubiquity in US food, feed, and fuel supply systems. We know that corn undergoes a lot of heat stress during growing season, with severe negative effects on these crops. Corn yields usually increase up to temperatures reaching 29 C/84.2 F. Any temperatures beyond that threshold are very harmful, and the losses in yield are much steeper beyond that threshold than the increases below it.

The USDA estimates there are more than 90 million acres of corn plantations in the US alone. With the looming prospect of global warming and the uncertainty it will impose on US and global food security, it is easy to see the urgency of improving corn and, in general, plant resistance to adverse environmental stressors such as heat. Beyond obvious and highly visible green solutions that should lead to a cleaner environment and more sustainable food systems, there are ways in which these plants can be genetically encouraged to better cope with the challenges they are bound to face.
 

How corn protects itself

Plants contain complex networks of communication and trafficking in order to properly function.

Within each plant cell, there is a massive manufacturing facility called the endoplasmic reticulum (ER) which produces and provides quality control over many of the plant’s proteins, the so-called building blocks necessary for life. In specific, proteins have to be folded into precise 3D structures during production. Only then can they perform their biological functions, be it for energy generation, growth, defense, etc.

After undergoing production and inspection, these proteins are sent over to the Golgi apparatus – which works like a post office – where they are “finished,” packaged and shipped off to the appropriate destinations within the plant cell.

Extreme stressors, such as heat, can negatively affect this system and lead to the production of misfolded or unfolded proteins that are useless to plants. There is a mechanism within the ER, called the unfolded protein response (UPR), by which plants perceive and respond to these conditions. When there is an accumulation of defective proteins in the ER, the system becomes overloaded. This situation activates the UPR, which then triggers genetic functions that restore normal performance, by temporarily halting protein production to stop the train wreck, clearing out the badly formed proteins, and signaling the increase of production of new and well-formed protein structures.

Out of the lab, into the ground

The NSF project goal is to better understand how the UPR functions in corn and to examine genetic ways of increasing resistance to environmental stressors.

Not much is known about how the relevant genes interact to successfully activate the UPR. (In contrast, these have been well studied in animals.) Consequently, the grant team will conduct research on the corn UPR response both in the lab and in two fields at the University of North Carolina and Iowa State.

Increasing this body of knowledge has both scientific intellectual and real world implications. For one, understanding how corn’s visible (physiological) and invisible (molecular and genetic) traits correlate could explain how ER stress can affect important plant characteristics such as seed weight or yield. For example, it has been already discovered that the UPR is deeply entwined in plant cell makeup and development.

On a more immediate scale, however, understanding those UPR genes could lead to the bioengineering of plants that do better Jiu jitsu in stressful situations. In specific, the grantees are interested in increasing the UPR’s reactivation of new protein production after undergoing “stress treatment” or optimizing how the UPR degrades damaged proteins.

All this aims towards increasing corn production efficiency. Even tiny increments towards this goal, as small as 1% to 5%, have massive effects on productivity (keep in mind those 90 million acres of corn plantation in the US alone), with potential improvements in such areas as food supply or biomass generation for those well-advertised green solutions inundating our collective consciousness, from POTUS speeches and government policy, to social media and everyday conversations.

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There will be new graduate and undergraduate positions throughout the duration of the grant. For more information, visit PRL’s graduate page in addition to Dr. Brandizzi’s faculty and lab pages. For inquiries, contact Dr. Brandizzi at fb@msu.edu.