ROS Signaling Mediates Directional Cell Elongation and Somatic Cell Fusion in the Red Alga Griffithsia monilis

Cells. 2022 Jul 5;11(13):2124. doi: 10.3390/cells11132124.

Abstract

In many filamentous red algae, cells that die from physical damage are replaced through somatic fusion of repair cells formed from adjacent cells. We visualized ROS generation in repair cells of Giriffthsia monilis using DCFH-DA staining and examined the expression of the genes involved in wound healing using quantitative PCR. Repair cells elongate along the H2O2 gradient, meet at each other's tips where the H2O2 concentration is highest, and undergo somatic fusion. No wound response occurred with ascorbic acid treatment. Conversely, H2O2 treatment induced many repair cells, leading to multiple somatic cell fusions. Diphenylene iodonium (DPI) or caffeine treatment reversibly inhibited ROS production in repair cells and blocked the progression of the wound response suggesting that ROS and calcium signaling are involved in the process. Four G. monilis homologues of NADPH-oxidase (GmRBOHs) were identified. The expression of GmRBOHs was upregulated upon injury, peaking 1 h post injury, and decreasing to initial levels when repair cells began to elongate. Our results suggest that ROS generated upon cell injury activates Ca2+ channels and upregulates the expression of GmRBOHs, and that H2O2 generated from repair cells mediates induced repair cell elongation leading to somatic cell fusion and filament repair.

Keywords: Griffithsia monilis; H2O2; ROS signal; somatic fusion; wound response.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium Signaling
  • Cell Fusion
  • Hydrogen Peroxide* / metabolism
  • Hydrogen Peroxide* / pharmacology
  • Reactive Oxygen Species / metabolism
  • Rhodophyta* / metabolism

Substances

  • Reactive Oxygen Species
  • Hydrogen Peroxide

Grants and funding

This research was supported by Development of technology for biomaterialization of marine fisheries by-products of Korea institute of Marine Scinece & Technology Promotion (KIMST) funded by the Ministry of Oceans and Fisheries (KIMST-20220128) and by National Marine Biodiversity Institute of Korea (2022M01100) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. 2019M3C1B7025093).