Yeping  Han¹ , Zhonggang  Li²

1 Institute of Life Science, Jiyang College of Zhejiang A&F University, Zhuji, 311800, China
2 Tropical Specialty Crops Research Center, Hainan Institute of Tropical Agricultural Resources, Sanya, 572000, Hainan, China
Author    Correspondence author
Biological Evidence, 2025, Vol. 15, No. 3   
Received: 02 Apr., 2025    Accepted: 14 May, 2025    Published: 28 May, 2025

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.

Pitaya (Hylocereus spp.) is a typical crassulacean acid metabolism (CAM) plant in the Cactaceae family, which can effectively utilize water through a special photosynthetic pathway in arid environments. This study reviews the evolutionary mechanism of the conversion of the photosynthetic pathway of pitaya from C3 to CAM, and elaborates on its carbon metabolism regulation characteristics. The taxonomic differences of C3, intrinsic CAM and inducible CAM photosynthesis in Cactaceae plants, as well as the structural and physiological characteristics related to CAM evolution, are compared. The circadian expression characteristics of key enzyme genes of pitaya CAM photosynthesis, the role of transcription factors involved in regulation, and the regulatory mechanisms at the epigenetic and post-transcriptional levels are analyzed. The dynamics of the accumulation and conversion of carbonate assimilates (such as malic acid, sugar and starch) in pitaya during the diurnal cycle, as well as the role of vacuolar carbonate transport in carbon allocation, are discussed. The conservation and novelty of CAM pathway-related genes in Cactaceae plants are explored from the perspective of comparative genomics, and the differences in the genomes of pitaya and its C3 relatives are compared. Through the case of red-fleshed and white-fleshed pitaya varieties, this study analyzed the changes in CAM expression levels and metabolome under drought and high temperature stress, and looked forward to applying CAM characteristics to pitaya stress resistance breeding to improve crop water use efficiency and stress resistance, and promote the efficient use of pitaya in sustainable agricultural development.

Pitaya (Hylocereus spp.); Crassulacean acid metabolism (CAM); Photosynthetic pathway; Carbon metabolism; Drought resistance and adaptation