Nitrogen and phosphorus deprivation led to the degradation of the highly abundant light-harvesting proteins so that they could be used as sources for protein synthesis [ 28].
Notably, we find that DNA damage or replication fork stress (with MMS), endoplasmic reticulum stress (with DTT), cell wall stress (with CPZ) and phosphorus deprivation are clearly Pph3-dependent stresses.
Phosphorus deprivation was included as it causes nuclear accumulation of tRNAs, similar to DNA damage (Ghavidel et al, 2007; Hurto et al, 2007), although whether it causes Pol III transcription repression or Maf1 dephosphorylation has not been tested.
LPB is important for acclimation of Chlamydomonas reinhardtii to phosphorus and sulfur deprivation [ 25]. 6-PGDH is the first enzyme for pentose phosphate pathway (PPP), which is common for plant responses to abiotic stresses, and serine/threonine protein kinase is required for acclimation of the alga to sulfur deprivation [ 26].
In contrast, phosphorus (P) and nitrogen (N) deprivation caused transcriptional changes in a vast number of genes in Arabidopsis[ 26, 27].
Because of the inherent connection between carbon, nitrogen, and phosphorus in biological systems, macronutrient deprivation has been proven to significantly enhance lipid accumulation in different diatom and algae species.
In several algae, nutritional stresses, for example, deprivation of nitrogen or phosphorus, limit cell growth, while increasing lipid [ 43, 56- 58] or carbohydrate [ 35, 59, 60] content.
Because of the inherent connection between carbon (C), nitrogen (N), and phosphorus (P) in biological systems, macronutrient deprivation has been proven to significantly enhance lipid accumulation in different diatom and algae species.
As some examples, calcium deprivation reduces the appetite for phosphorus, and hunger inhibits sexual behavior (Dickinson & Balleine, 2002).
The increased expression of cycB1 suggests a role during cell-cycle arrest induced by nutrient deprivation of both nitrogen and phosphorus.
However, evidence for urinary silicon conservation (to maintain tissue levels), changes in bone/body lengths, bone calcium:phosphorus ratio and differences at the growth plate with silicon deprivation are all novel and deserve further study.
