Modulatory Role Of Reactive Oxygen Species In Root Development In Model Plant Ofarabidopsis Thaliana

Reactive oxygen species (ROS), a type of oxygen monoelectronic reduction product, have a higher chemical activity than O-2. Although ROS pose potential risks to all organismsviainducing oxidative stress, indispensable role of ROS in individual development cannot be ignored. Among them, the role of ROS in the model plantArabidopsis thalianais deeply studied. Mounting evidence suggests that ROS are essential for root and root hair development. In the present review, we provide an updated perspective on the latest research progress pertaining to the role of ROS in the precise regulation of root stem cell maintenance and differentiation, redox regulation of the cell cycle, and root hair initiation during root growth. Among the different types of ROS, O(2)(center dot-)and H(2)O(2)have been extensively investigated, and they exhibit different gradient distributions in the roots. The concentration of O(2)(center dot-)decreases along a gradient from the meristem to the transition zone and the concentration of H(2)O(2)decreases along a gradient from the differentiation zone to the elongation zone. These gradients are regulated by peroxidases, which are modulated by the UPBEAT1 (UPB1) transcription factor. In addition, multiple transcriptional factors, such as APP1, ABO8, PHB3, and RITF1, which are involved in the brassinolide signaling pathway, converge as a ROS signal to regulate root stem cell maintenance. Furthermore, superoxide anions (O-2(center dot-)) are generated from the oxidation in mitochondria, ROS produced during plasmid metabolism, H(2)O(2)produced in apoplasts, and catalysis of respiratory burst oxidase homolog (RBOH) in the cell membrane. Furthermore, ROS can act as a signal to regulate redox status, which regulates the expression of the cell-cycle components CYC2;3, CYCB1;1, and retinoblastoma-related protein, thereby controlling the cell-cycle progression. In the root maturation zone, the epidermal cells located in the H cell position emerge to form hair cells, and plant hormones, such as auxin and ethylene regulate root hair formationviaROS. Furthermore, ROS accumulation can influence hormone signal transduction and vice versa. Data about the association between nutrient stress and ROS signals in root hair development are scarce. However, the fact thatROBHC/RHD2orRHD6is specifically expressed in root hair cells and induced by nutrients, may explain the relationship. Future studies should focus on the regulatory mechanisms underlying root hair developmentviathe interactions of ROS with hormone signals and nutrient components.