International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.6, 286-293 http://ecoevopublisher.com/index.php/ijmec 286 Feature Review Open Access Genomic Evolutionary Uniqueness of Pineapple: CAM Photosynthesis, Chromosomal Rearrangement, and Gene Duplication Clusters ZhenLi 1, Zhonggang Li 2 1 Hainan Institute of Biotechnology, Haikou, 570206, Hainan, China 2 Hainan Institute of Tropical Agricultural Resources, Sanya, 572025, Hainan, China Corresponding email: zhonggang.li@hitar.org International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.5 doi: 10.5376/ijmec.2025.15.0029 Received: 29 Sep., 2025 Accepted: 16 Nov., 2025 Published: 01 Dec., 2025 Copyright © 2025 Li and Li, This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Preferred citation for this article: Li Z., and Li Z.G., 2025, Genomic evolutionary uniqueness of pineapple: CAM photosynthesis, chromosomal rearrangement, and gene duplication clusters, International Journal of Molecular Ecology and Conservation, 15(6): 286-293 (doi: 10.5376/ijmec.2025.15.0029) Abstract This study systematically analyzes recent research progress on the pineapple (Ananas comosus) genome, focusing on three key evolutionary features: the transition from C3 to CAM photosynthesis, chromosomal rearrangements, and the evolution of gene duplication clusters. Major findings indicate that during its evolutionary history, pineapple underwent limited whole-genome duplication events, retained a relatively conserved karyotype of seven chromosomes, and achieved functional gene expansion and diversification through segmental duplications and chromosomal structural rearrangements. By constructing an integrated framework of pineapple genome evolution, this study provides both theoretical foundations and practical guidance for future research on monocot evolution and the molecular breeding of crops with enhanced stress tolerance traits. Keywords CAM photosynthesis; Chromosomal rearrangement; Gene duplication; Pineapple genome; Monocot evolution 1 Introduction Pineapple (Ananas comosus) is a popular tropical fruit grown in many regions around the world. It ranks second in terms of cultivation and consumption among tropical fruits, second only to bananas. In addition to its significant economic value, pineapple also has some unique genetic characteristics, which makes it an important model plant for studying the evolutionary mechanisms of bromeliads and CAM (crassulacean acid metabolism) photosynthesis (Xu et al., 2018). Compared with many other monocots, pineapple has a relatively simple genome structure, which allows researchers and breeders to study its genetic characteristics in more depth. In terms of evolutionary characteristics, pineapple shows some significant differences. One of the important changes is the shift in its photosynthesis pathway from C3 to CAM. This shift did not originate from a large-scale genome duplication event, but rather from a change in the way the expression of existing genes was regulated (De La Harpe et al., 2020). In other words, pineapple did not adapt by acquiring a large number of new genes, but instead completed the functional transformation by "modifying old genes." In addition, compared with other monocots, pineapple has experienced fewer whole genome duplication events, and its chromosome number has remained relatively stable during evolution, which reflects the strong structural conservation of its genome (Zhang et al., 2014). This study analyzes the research progress on the pineapple genome in recent years, focusing on its particularity in CAM photosynthesis, chromosome evolution, and gene duplication. By integrating multiple research results, this article helps to deepen our understanding of the evolution mechanism of pineapple genome and its environmental adaptation strategy. Related findings are also expected to provide ideas for future crop breeding in arid areas, especially in using CAM pathways to improve drought resistance. 2 Evolutionary History and Genomic Insights of Pineapple 2.1 Phylogenetic placement of pineapple in the bromeliaceae family In the Bromeliaceae family, pineapple (Ananas comosus) occupies a special position and is often used as a model plant for studying the evolutionary history of plants in this family and the CAM (crassulacean acid metabolism) photosynthesis mechanism (Xu et al., 2018). As the research deepened, the scientific community merged Ananas and Pseudananas, which originally belonged to two genera, into one genus. Today, this genus contains two
RkJQdWJsaXNoZXIy MjQ4ODYzNA==