Guard-cell-targeted overexpression of Arabidopsis Hexokinase 1 can improve water use efficiency in field-grown tobacco plants

Authors

Liana G. Acevedo-Siaca, International Maize and Wheat Improvement Center, University of Illinois at Urbana-Champaign
Katarzyna Glowacka, University of Nebraska - LincolnFollow
Steven M. Driever, University of Illinois at Urbana-Champaign
Coralie E. Salesse-Smith, University of Illinois at Urbana-Champaign
Nitsan Lugassi, Institute of Plant Sciences- The Volcani Center
David Granot, Institute of Plant Sciences- The Volcani Center
Stephen P. Long, University of Illinois at Urbana-Champaign, University of Lancaster
Johannes Kromdijk, University of Illinois at Urbana-Champaign, Wageningen University

Document Type

Article

Date of this Version

5-18-2022

Citation

Journal of Experimental Botany https://doi.org/10.1093/jxb/erac218

Comments

Open Access

Abstract

Water deficit currently acts as one of the largest limiting factors for agricultural productivity worldwide. Additionally, limitation by water scarcity is projected to continue in the future with the further onset of effects of global climate change. As a result, it is critical to develop or breed for crops that have increased water use efficiency and that are more capable of coping with water scarce conditions. However, increased intrinsic water use efficiency (iWUE) typically brings a trade-off with CO₂ assimilation as all gas exchange is mediated by stomata, through which CO₂ enters the leaf while water vapor exits. Previously, promising results were shown using guard-cell-targeted overexpression of hexokinase to increase iWUE without incurring a penalty in photosynthetic rates or biomass production. Here, two homozygous transgenic tobacco (Nicotiana tabacum) lines expressing Arabidopsis Hexokinase 1 (AtHXK1) constitutively (35SHXK2 and 35SHXK5) and a line that had guard-cell-targeted overexpression of AtHXK1 (GCHXK2) were evaluated relative to wild type for traits related to photosynthesis and yield. In this study, iWUE was significantly higher in GCHXK2 compared with wild type without negatively impacting CO₂ assimilation, although results were dependent upon leaf age and proximity of precipitation event to gas exchange measurement.