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

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 CO 2 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.

Comparative genomics can provide new insights into the evolutionary mechanisms and gene function in CAM plants

“…In comparison with C 3 species, changes in the expression of a large number of protein-encoding genes were also revealed in other comparative analyses of constitutive CAM plant species such as Agave (Abraham et al , 2016; Yin et al , 2018) and Ananas comosus (Ming et al , 2015). Additionally, many genes, including transcription factors, are potentially involved in CAM induction in facultative CAM plants such as Mesembryanthemum crystallinum (Amin et al , 2019). Besides protein-encoding genes, microRNAs (miRNAs) are likely involved in CAM gene regulation (Wai et al , 2017).…”

“…Recently, Brilhaus et al (2016) and Maleckova et al (2019) identified candidate transcription factors potentially involved in the regulation of the C 3 -to-CAM transition in the facultative CAM species Talinum triangulare , which is capable of reversible transitioning from C 3 photosynthesis to weak CAM in response to drought stress. More recently, eight transcription factors were identified as potential candidates regulating the induction of CAM by water-deficit stress in another facultative CAM species, Mesembryanthemum crystallinum (Amin et al , 2019). These comparative genomics analyses of stress-induced CAM versus C 3 photosynthesis provide insights into the course of CAM evolution.…”

Undervalued potential of crassulacean acid metabolism for current and future agricultural production

“…Recent advances in the understanding of CAM gene expression lay the groundwork for potential genetic engineering of CAM to improve crop tolerance (e.g. Amin et al , 2019; Lim et al , 2019).…”

Irrigation Intervals in the Production of Ornamental Pineapple in Pots1

“…Furthermore, it is possible that the CAM also reduced the effects of water deficit in the absence of rainfall, due to the plants adapting to the stress caused by the lack of water. As discussed above, CAM plants close their stomata during the day to reduce water loss and open them at night to increase CO 2 fixation, which results in greater water use efficiency and therefore greater resistance to drought (AMIN et al, 2019).…”