Research Progress on CFEM Proteins in Phytopathogenic Fungi

In the process of infecting plants, pathogenic fungi may often secrete effectors to increase pathogenicity, or conversely, be recognized by the host to trigger resistance. Hence, such effectors are crucial for the well-being of a plant at time of a pathogenic intrusion. As an effector, CFEM (common in fungal extracellular membrane) protein is found only in the outer membrane of a fungal pathogen. This article reviews the origin, evolution, growth, development, structural characteristics, expressions and localization in different species, and intracellular iron absorption regulations of the CFEM protein family as well as the host immunology and infection-promoting factors associated with the proteins in the phytopathogens. Some of the yet-to-be-clarified issues on the molecular mechanisms and plant-pathogen interactions relating to CFEM proteins are discussed to facilitate the cultivation of disease-resistant plants and the development of ecologically friendly disease control strategies on crops.