The role of cis-elements in the evolution of crassulacean acid metabolism photosynthesis
Li-Yu Chen1, Yinghui Xin2, Ching Man Wai2, Juan Liu1 & Ray Ming1,2,
1FAFU and UIUC Joint Center for Genomics and Biotechnology, Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Genetics, Breeding and Multiple Utilization of Crops, Ministry of Education, Fujian Agriculture and Forestry University, 350002 Fuzhou, Fujian, China
2Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
Received: 23 Aug 2019 Revised: 01 Dec 2019 Accepted: 04 Dec 2019 Published online: 01 Jan 2020
Crassulacean acid metabolism (CAM) photosynthesis is an innovation of carbon concentrating mechanism that is characterized by nocturnal CO2 fixation. Recent progresses in genomics, transcriptomics, proteomics, and metabolomics of CAM species yielded new knowledge and abundant genomic resources. In this review, we will discuss the pattern of cis-elements in stomata movement-related genes and CAM CO2 fixation genes, and analyze the expression dynamic of CAM related genes in green leaf tissues. We propose that CAM photosynthesis evolved through the re-organization of existing enzymes and associated membrane transporters in central metabolism and stomatal movement-related genes, at least in part by selection of existing circadian clock cis-regulatory elements in their promoter regions. Better understanding of CAM evolution will help us to design crops that can thrive in arid or semi-arid regions, which are likely to expand due to global climate change.