Transcriptome for Photobiological Hydrogen Production Induced by Sulfur Deprivation in the Green Alga Chlamydomonas reinhardtii

Abstract

Photobiological hydrogen production using microalgae is being developed into a promising clean fuel stream for the future. In this study, microarray analyses were used to obtain global expression profiles of mRNA abundance in the green alga Chlamydomonas reinhardtii at different time points before the onset and during the course of sulfur-depleted hydrogen production. These studies were followed by real-time quantitative reverse transcription-PCR and protein analyses. The present work provides new insights into photosynthesis, sulfur acquisition strategies, and carbon metabolism-related gene expression during sulfur-induced hydrogen production. A general trend toward repression of transcripts encoding photosynthetic genes was observed. In contrast to all other LHCBM genes, the abundance of the LHCBM9 transcript (encoding a major lightharvesting polypeptide) and its protein was strongly elevated throughout the experiment. This suggests a major remodeling of the photosystem II light-harvesting complex as well as an important function of LHCBM9 under sulfur starvation and photobiological hydrogen production. This paper presents the first global transcriptional analysis of C. reinhardtii before, during, and after photobiological hydrogen production under sulfur deprivation.

Repression of Essential Chloroplast Genes Reveals New Signaling Pathways and Regulatory Feedback Loops inChlamydomonas

“…The decrease was larger for RR5 than for DPF1 in the light but the opposite occurred in the dark for Lhca1 and Lhcbm1. By contrast, Lhcbm9, which is known to be induced under stress conditions, was increased in the light and in the dark in both RR5 and DPF1 (Nguyen et al, 2008).…”

Genetic Interactions Between Regulators of Chlamydomonas Phosphorus and Sulfur Deprivation Responses

“…The specific S-deprivation responses include an elevated rate of extracellular SO 4 2À uptake , secretion of extracellular arylsulfatases (Lein and Schreiner 1975;de Hostos et al 1988), and an increased cellular capacity to assimilate SO 4 2À by increasing levels of enzymes required for cysteine biosynthesis (Ravina et al 2002). Mechanisms for conserving S during limiting conditions include the rapid turnover of sulfolipids and their replacement with phospholipids (Sugimoto et al 2007(Sugimoto et al , 2008, the synthesis of putative cell wall proteins with a very low abundance of S-containing amino acids , and a potential change in the polypeptide composition of light harvesting complexes, favoring the synthesis of complexes with polypeptides containing low levels of sulfur amino acid (Nguyen et al 2008). Many S starvation-elicited responses appear to be controlled, at least in part, at the level of gene expression.…”

Changes in Transcript Abundance in Chlamydomonas reinhardtii following Nitrogen Deprivation Predict Diversion of Metabolism

“…html). At this time, a number of microarrays have been used to interrogate changes in response to environmental factors (Ledford et al, 2004(Ledford et al, , 2007Jamers et al, 2006;Mus et al, 2007;Nguyen et al, 2008;Simon et al, 2008;Yamano et al, 2008;Mustroph et al, 2010). These microarrays could not cover all genes in the genome, but more recently, massively parallel cDNA sequencing approaches were applied to C. reinhardtii, overcoming the shortcomings of microarrays (González-Ballester et al, 2010).…”