Nitrogen and sulfur deprivation differentiate lipid accumulation targets of Chlamydomonas reinhardtii

Critical Function of a Chlamydomonas reinhardtii Putative Polyphosphate Polymerase Subunit during Nutrient Deprivation

“…The unicellular green alga Chlamydomonas reinhardtii (Chlamydomonas throughout) has been a powerful model organism for dissecting responses of photosynthetic eukaryotes to nutrient deprivation, including deprivation for iron (BlabyHaas and Merchant, 2012;Page et al, 2012;Urzica et al, 2012Urzica et al, , 2013Hsieh et al, 2013), nitrogen (N) (Miller et al, 2010;Boyle et al, 2012;Blaby et al, 2013), and phosphorus (P) (Moseley et al, 2006Yehudai-Resheff et al, 2007;, and S González-Ballester et al, 2010;Cakmak et al, 2012aCakmak et al, , 2012bAksoy et al, 2013;Schmollinger et al, 2014). Processes induced by S deprivation in this alga include rapid changes in cell size (Zhang et al, 2002), elevated production of hydrolytic extracellular enzymes (de Hostos et al, 1988;Takahashi et al, 2001), alterations in cell wall structure (Takahashi et al, 2001), changes in the activities and composition of the photosynthetic apparatus (Collier and Grossman, 1992;Wykoff et al, 1998;Zhang et al, 2004;González-Ballester et al, 2010;Cakmak et al, 2012aCakmak et al, , 2012bAksoy et al, 2013), scavenging of S from intracellular structures/molecules, elevated SO 4 22 transport activity Pootakham et al, 2010), and the synthesis of enzymes required for efficient S assimilation (Ravina et al, 1999(Ravina et al, , 2002González-Ballester et al, 2010).…”

Cross-Effects of Nitrogen and Sulphur Starvation in <i>Chlorella sorokiniana</i> 211/8K

“…In addition, in the process of acclimation to long term N-deficiency, microalgae have been reported to degrade ribosomes and decrease enzyme activities involved in gluconeogenesis and photosynthetic carbon fixation cycle [1]. These effects of N-starvation recall in many aspects those observed following S-deprivation.…”

“…Several studies indicate the degradation of PSII as responsible for this decrease [23]. Chlamydomonas reinhardtii is known to restructure its photosynthetic machinery upon S-deprivation to minimize oxidative stress that may occur in conditions of reduced photosynthesis [1]. As such, the decrease in chlorophyll content could be ascribed to the deactivation and disassembly of photosynthetic complexes as a response to oxidative stress resulting from S-starvation.…”

“…As such, the decrease in chlorophyll content could be ascribed to the deactivation and disassembly of photosynthetic complexes as a response to oxidative stress resulting from S-starvation. As well, protein degradation that occurs in N-starved cells does not save the enzyme ribulose-1,5- bisphosphate carboxylase oxygenase [1] [24] and the depletion of this protein may compromise the mechanism of photosynthesis, leading to the decrease in chlorophyll content observed in N-deficient Chlorella cells.…”

“…In this context, a Chlorella sorokiniana suspension that contained all nutrients in sufficient concentration showed a growth constant of 3 d −1 . In microalgae, long-term nutrient deprivation can lead to the cell death preceded by autophagy, a self-degrading process to recycle part of the cytoplasm including organelles [1].…”