Cellular responses associated with ROS production and cell fate decision in early stress response to iron limitation in the diatom Thalassiosira pseudonana.
Investigation of how diatoms cope with the rapid fluctuations in iron bioavailability in marine environments may facilitate a better understanding of the mechanisms underlying their ecological success, in particular their ability to proliferate rapidly during favorable conditions. In this study, using in vivo biochemical markers and whole-cell iTRAQ-based proteomics analysis, we explored the cellular responses associated with reactive oxygen species (ROS) production and cell fate decision during the early response to Fe limitation in the centric diatom Thalassiosira pseudonana. Fe limitation caused a significant decrease in Photosystem (PS) II photosynthetic efficiency, damage to the photosynthetic electron transport chain in PS I, and blockage of the respiratory chain in complexes III and IV, which could all result in excess ROS accumulation. The increase in ROS likely triggered programmed cell death (PCD) in some of the Fe-limited cells through synthesis of a series of proteins involved in the delicate balance between pro-survival and pro-PCD factors. The results provide molecular-level insights into the major strategies that may be employed by T. pseudonana in response to Fe-limitation: the reduction of cell population density through PCD to reduce competition for available Fe, the reallocation of intracellular nitrogen and Fe to ensure survival, and an increase in expression of antioxidant and anti-PCD proteins to cope with stress.
School of Life Sciences, Xiamen University , Xiamen 361102, People's Republic of China.
Chun-Shan
CS
Luo
Jun-Rong
JR
Liang
Qun
Q
Lin
Caixia
C
Li
Chris
C
Bowler
Donald M
DM
Anderson
Peng
P
Wang
Xin-Wei
XW
Wang
Ya-Hui
YH
Gao
D000222:Adaptation, Physiological; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D002853:Chromatography, Liquid; D017377:Diatoms / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D014450:Electron Transport Complex III / Q000235:genetics / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression; D007501:Iron / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods; D046529:Microscopy, Electron, Transmission; D010788:Photosynthesis / Q000235:genetics; D045332:Photosystem II Protein Complex / Q000235:genetics / Q000378:metabolism; D020543:Proteome / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013312:Stress, Physiological
D000975:Antioxidants; D045332:Photosystem II Protein Complex; D020543:Proteome; D017382:Reactive Oxygen Species; D007501:Iron; D003576:Electron Transport Complex IV; D014450:Electron Transport Complex III
Fe-limitation stress; diatom; iTRAQ-based proteomics; phytoplankton; programmed cell death (PCD); reactive oxygen species (ROS)