###### Abstract  
Rapid industrializing during recent decades has resulted in the widespread contamination by cadmium (Cd) of agricultural soils, which has become a ubiquitous environmental problem and poses great risk to human health via the food chain. Cd accumulation greatly varies among different plant species and even within different genotypes of the same species across the plant kingdom. A better understanding of the physiological and molecular mechanisms underlying Cd uptake, translocation, sequestration, and (re)distribution in plants will shed light on developing strategies to minimize Cd in crops. Moreover, analysis of molecular evolution of the key transporters reveals that Cd transporters were highly conserved throughout the evolutionary lineage of the entire plant kingdom and underwent lineage-specific expansion as the result of gene duplication. However, different Cd transporters may experience different evolutionary lineages from algae to angiosperms, suggesting the divergence of their roles in plant adaptation to metalloprotein soil. In summary, all the knowledge in the present review can be used to predict the transfer of Cd from soils to plants, to further understand the origins of Cd-accumulating phenotypes, and to discover the plant genetic resources for the breeding of low-Cd crops and the phytoremediation of Cd-contaminated soils. cadmium; phylogenetic variation; membrane transporters; evolution; uptake; translocation; sequestration; (re)distribution 2023151215810  
growth and development and eventually plant death [4; 7]. Due to consuming agricultural products with excessive levels of Cd, the Cd accumulated in plants is easily absorbed and stored in humans through the food chain. Such excessive intake of Cd causes severely detrimental effects on human health, including cancer diseases in kidney and breast; cardiovascular and cerebrovascular diseases like hypertension, anemia, heart failure, and cerebral infarction; and renal diseases like proteinuria and renal insufficiency [2]. It is well known that humans are exposed to Cd mainly through the consumption of crops, which account for 90% of the total dietary Cd intake [5]. Therefore, it is of great importance to develop crop cultivars with reduced Cd accumulation (especially in the edible parts like grains) to minimize the harm caused by Cd to human health. To reach this goal, it is imperative to obtain a comprehensive understanding of the mechanisms underlying Cd accumulation in plants. Over the last decade, a great deal of research has focused on revealing the physiological and molecular mechanisms of Cd uptake and accumulation [2; 6]. A series of genes associated with Cd transport in plants have been identified and functionally verified [4; 6; 7; 8]. Meanwhile, specific plant genotypes or lines with extremely low or high Cd accumulation potential have been developed by genetic transformation and gene editing [9]. Furthermore, there is increasing evidence indicating that Cd accumulation and tolerance in some plant species might have evolved under the selection pressure for their colonization in metal-liferous soils or to protect them against herbivores or pathogens [10]. However, there are still many questions far from being clearly answered, such as the following: How does Cd accumulation vary across the plant kingdom? How is the trait of Cd accumulation evolved? What is the molecular basis driving the evolution of Cd accumulation in plants? Is there any relationship between the physiological/molecular mechanisms of Cd accumulation and evolutionary adaptation? To answer these questions, the present review firstly analyzed the phylogenetic variation in Cd accumulation among plant species with the available research data.