| Iron homeostasis plays an important role in physiological and biochemical processes such as cell morphological maintenance and photosynthesis.Higher plants have evolved two strategies to obtain insoluble Fe3+from soil:reduction-based strategyⅠfor non-gramineous plants,and chelating-based strategyⅡfor gramineous plants.However,a combination of strategy I and strategy II for iron absorption was found in rice.This has important implications for elucidating the evolution of iron homeostasis-related proteins and their role in plant organogenesis and reproduction,as well as for exploring the evolutionary history of iron uptake strategies.Wheat（Triticum aestivum L.）is a representative species of the grass family.As one of the most important staple crops in the world,it is very important for global food security.Exploring the evolution and regulation mechanism of iron homeostasis-related proteins in the grass family is of great significance for improving wheat yield and quality as well as improving wheat health function.This helps to accelerate the biological fortification process of iron.In the present study,we systematically identified 9 classes of iron-transport-related proteins involved in two iron uptake strategies in 339 plant species,explored the distribution and phylogeny of the two iron uptake strategies in plants and their contributions to organogenesis and reproduction during the evolution of terrestrial plants.And explored the characteristics and expression patterns of iron homeostasis-related genes in wheat and its ancestral donors.It provided a new idea for the analysis of iron absorption mechanisms in plants.The main results of the study are as follows:（1）339 representative plant species were selected to systematically identify the family members of iron homeostasis-related proteins PEZ,HA,FRO,IRT,NAS,NAAT,DMAS,TOM and YSL.Phylogenetic analysis suggested that these families expanded significantly during the evolution of plants from low to high.This is especially true in the monocotyledon group of angiosperms.In addition,strategyⅡrelated genes had a higher abundance in gramineous plants.（2）According to the expression patterns of iron homeostasis regulation genes in 13phylogenetic representative species,it was found that some genes of NAAT and DMAS can respond to circadian rhythm changes and stress such as nitrogen starvation and sulfur starvation in algae,but most iron homeostasis-related genes are not actively expressed in the development of male and female gametophytes and related tissues.These genes are less involved in the reproductive growth process of plants,and the expression of these genes is spatio-temporal specific.（3）By analyzing the composition,structure,evolution and expression patterns of genes related to iron homeostasis regulation in wheat and its ancestor species,it was found that the quantity distribution of 9 types of proteins was relatively balanced among all species,and it was speculated that PEZ gene of bread wheat may have originated from B subgenome donors.Cis-acting element analysis revealed that iron homeostasis-related genes may be associated with plant photosynthesis and stress response mechanisms,suggesting that the maintenance of iron homeostasis plays an important role in the vegetative growth and environmental adaptability of wheat.（4）Six hub genes were discovered from 577 iron homeostasis-related genes of bread wheat using transcriptome data.Gene expression analysis has shown that they have different mechanisms of response to low and high iron environments,affecting root development and plant phenotypes at the seedling stage.However,most of the hub genes were not selected during wheat improvement and acclimation. |
