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

Abstract

Crassulacean acid metabolism (CAM) photosynthesis is an important biological innovation enabling plant adaptation to hot and dry environments. CAM plants feature high water-use efficiency, with potential for sustainable crop production under water-limited conditions. A deep understanding of CAM-related gene function and molecular evolution of CAM plants is critical for exploiting the potential of engineering CAM into C3 crops to enhance crop production on semi-arid or marginal agricultural lands. With the newly emerging genomics resources for multiple CAM species, progress has been made in comparative genomics studies on the molecular basis and subsequently on the evolution of CAM. Here, recent advances in CAM comparative genomics research in constitutive and facultative CAM plants are reviewed, with a focus on the analyses of DNA/protein sequences and gene expression to provide new insights into the path and driving force of CAM evolution and to identify candidate genes involved in CAM-related biological processes. Potential applications of new computational and experimental technologies (e.g. CRISPR/Cas-mediated genome-editing technology) to the comparative and evolutionary genomics research on CAM plants are offered.

Editorial: Systems Biology and Synthetic Biology in Relation to Drought Tolerance or Avoidance in Plants

“…Therefore, engineering drought-inducible CAM (or CAM-on-demand) systems would be ideal. In nature, CAM can be induced by drought stress in facultative CAM plants, which perform C 3 photosynthesis under well-watered conditions (Winter, 2019;Yang et al, 2019a). In this Research Topic, Amin et al proposed a strategy for engineering of CAMon-demand systems based on the engineering of droughtresponsive transcription factors (TFs) in multiple gene families (e.g., AP2/ERF, MYB, WRKY, NAC, NF-Y, bZIP) from the facultative CAM plant M. crystallinum and obligate CAM plant K. fedtschenkoi.…”

New perspectives on crassulacean acid metabolism biology

“…Comparative transcriptome and preliminary metabolomic analyses of a 24 h time course comparing Yucca (Asparagaceae) species with C 3 photosynthesis ( Y. filamentosa ), C 3 –CAM [ Y. gloriosa (hybrid)], and CAM ( Y. aloifolia ) under both well-watered and drought-stressed conditions in a common garden setting revealed clear-cut differences among the two parents and the hybrid, yet all three shared some common changes in steady-state mRNA abundance Such common expression patterns and resulting traits might have facilitated the convergent evolution of CAM within the Agavoideae (Heyduk et al , 2019). In the context of CAM evolution, Yang et al (2019) discuss possible pathway scenarios for CAM evolution, anatomical modifications associated with CAM, and potential amino acid and temporal reprogramming changes that might sustain CAM evolution informed by comparative genomic analyses. Taking a phylogenetic approach and using δ 13 C tissue analysis of herbarium specimens, Li et al (2019) report multiple independent origins of CAM within the highly diverse orchid genus Dendrobium in Australasia (Li et al , 2019).…”

Model approaches to advance crassulacean acid metabolism system integration

“…Finally, additional layers of control are also being explored at the level of post‐transcriptional regulation via microRNA (miRNA) as well as less conventional mechanisms such as long non‐coding RNA (lncRNA) which could function competitively with endogenous RNAs to alter the expression profile of key CAM pathway genes such as PEPC and PPDK (Yang et al , ; Wai et al , ; Bai et al , ). Hence, computational modelling is becoming increasingly important to make sense of the explosion of data in the genomics era and not be deafened by the associated noise (Schatz, ; Fernie, ; Smita et al , ; Yang et al , ).…”