Crassulacean Acid Metabolism Abiotic Stress-Responsive Transcription Factors: a Potential Genetic Engineering Approach for Improving Crop Tolerance to Abiotic Stress.

Atia B. Amin,Kumudu N. Rathnayake,Bernard W. M. Wone,Beate Wone,Won C. Yim,John C. Cushman,Travis M. Garcia

doi:10.3389/fpls.2019.00129

Atia B. Amin, Kumudu N. Rathnayake + Show 5 more

Open Access

https://doi.org/10.3389/fpls.2019.00129

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Abstract

This perspective paper explores the utilization of abiotic stress-responsive transcription factors (TFs) from crassulacean acid metabolism (CAM) plants to improve abiotic stress tolerance in crop plants. CAM is a specialized type of photosynthetic adaptation that enhances water-use efficiency (WUE) by shifting CO2 uptake to all or part of the nighttime when evaporative water losses are minimal. Recent studies have shown that TF-based genetic engineering could be a useful approach for improving plant abiotic stress tolerance because of the role of TFs as master regulators of clusters of stress-responsive genes. Here, we explore the use of abiotic stress-responsive TFs from CAM plants to improve abiotic stress tolerance and WUE in crops by controlling the expression of gene cohorts that mediate drought-responsive adaptations. Recent research has revealed several TF families including AP2/ERF, MYB, WRKY, NAC, NF-Y, and bZIP that might regulate water-deficit stress responses and CAM in the inducible CAM plant Mesembryanthemum crystallinum under water-deficit stress-induced CAM and in the obligate CAM plant Kalanchoe fedtschenkoi. Overexpression of genes from these families in Arabidopsis thaliana can improve abiotic stress tolerance in A. thaliana in some instances. Therefore, we propose that TF-based genetic engineering with a small number of CAM abiotic stress-responsive TFs will be a promising strategy for improving abiotic stress tolerance and WUE in crop plants in a projected hotter and drier landscape in the 21st-century and beyond.

Highlights

Formidable challenges facing humankind include a burgeoning global human population (Godfray et al, 2010; Gerland et al, 2014) and the increasing frequency and intensity of droughts related to global warming (Cook et al, 2014; Singh et al, 2015)
It would be interesting to attempt to reprogram a C3 plant such that it becomes crassulacean acid metabolism (CAM) performing, we are not suggesting to shift gene expression patterns of CAM pathway genes that might be present in extant C3 plants, or to regulate the engineered CAM pathway in C3 plants (Yang et al, 2015; Fernie, 2016; Heyduk et al, 2018; Yin et al, 2018), but rather identify and exploit the transcription factors (TFs) involved in abiotic stress responses from obligate and inducible CAM plants to modulate the expression of appropriate genes in C3 plants to improve their abiotic stress tolerance
The abiotic stress-adaptive features of CAM plants provide a wealth of genetic resources, TFs, that are available for functional testing and possible improvement of water-use efficiency (WUE) and abiotic stress responses in C3 photosynthesis plants

Summary

Introduction

Formidable challenges facing humankind include a burgeoning global human population (Godfray et al, 2010; Gerland et al, 2014) and the increasing frequency and intensity of droughts related to global warming (Cook et al, 2014; Singh et al, 2015). Identification of candidate CAM pathway regulators (i.e., TFs) that are expressed or activated under water-deficit stress or CAM should be prioritized to exploit the molecular and regulatory machinery of abiotic stress adaptation in CAM plants as a vital resource for applications in C3 crop species (Yang et al, 2015; Fernie, 2016; Yin et al, 2018).

Results

Conclusion