A multifaceted approach to identifying targets for the improvement of water-use efficiency in Zea mays

Current climate projections and the need for sustainability require the development of more efficient crops. With fresh water resources declining and precipitation patterns becoming more sporadic, severe drought scenarios are becoming a normal occurrence during production seasons. Current methods for quantifying water-use efficiency (WUE) in C4 crops are not able to screen large quantities of lines. Stable carbon isotope composition (δ13C) has been successfully used to breed for higher WUE in C3 crops. This has not been the case in C4 species due to their more complex photosynthetic mechanism. We present data demonstrating that leaf δ13C variation exists across lines of Z. mays, and is a heritable trait. Appropriate and optimal leaf δ13C sample collection was determined through developmental and circadian time courses as a means to standardize the use of δ13C as a proxy trait for transpiration efficiency. In addition, the relationship between δ13C and transpiration was established. The use of leaf δ13C has the potential to be used as a breeding tool to increase the transpiration efficiency and WUE of maize. Atmospheric CO2 has increased over the past decade and projections show greater increases in the future. Understanding how stomata will respond to high atmospheric CO2 concentrations and accompanying environmental changes is necessary for the production of efficient crops. Stomata are the major avenue for CO2 uptake and also the avenue for transpirational water loss. As a result, a balance between CO2 integration and water loss is important for desirable photosynthetic rates while maintaining a healthy plant water status. The CO2 stomatal signaling pathway was previously elucidated in the dicot species A. thaliana. We characterized orthologs believed to hold importance in the Z. mays CO2 signaling pathway using genetic mutants and gas exchange physiology. By identifying the mechanisms stomata use to respond to varying CO2 levels in Z. mays, we can begin to engineer stomatal dynamics to produce an efficient crop under changing climates.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Crop Sciences

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2019

Author dc:creator

• Twohey III, Robert James

Contributors dc:contributor

• Studer, Anthony J
• Sachs, Martin
• Leakey, Andrew

• Zea mays
• Stomata
• Stable Carbon Isotopes
• WUE

Statement dc:rights

• Copyright 2019 Robert James Twohey III

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/105827

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/105827