Project description:Phosphorus (P) is an essential nutrient that is limiting in many environments. When P is scarce organisms employ strategies for conservation of internal stores, and to efficiently scavenge P from their external surroundings. In this study we investigated the acclimation response of Chlamydomonas reinhardtii to P deficiency, comparing the transcriptional profiles of P starved wild-type cells to the P replete condition. RNA was prepared from P-containing or P-deprived logarithmic growth phase cells and subjected to RNA-Seq analysis. During the 24 hours after the imposition of P starvation we observed that from the 407 significantly changing genes (> 2 fold change, corrected p-value < 0.05) in the wild-type 317 genes were up-regulated, in average 8.36-fold, and 90 genes were down-regulated by 3.43-fold, in average. Many of the upregulated genes encoded enzymes involved in specific responses to P starvation, including PHOX, encoding the major secreted alkaline phosphatase, and multiple putative, high-efficiency phosphate transporter genes. More general responses included the up-regulation of genes involved in photoprotective processes (LHCSR3, LHCSR1, LHCBM9, PTOX1) and genes involved in protein modification and degradation. Down-regulated mRNAs indicated an early stage of the reduction of chloroplast ribosomal proteins, which are considered to be a reservoir for P in the cell. Chlamydomonas reinhardtii strain 21 gr (CC1690, wild-type) grown in TAP medium (Harris 1989) in a rotary incubator (200 rpm) at 25 M-BM-0C in continuous light (70 M-BM-5mol m-2 s-1). For 24 hours, either 1.1 mM phosphate or 0 mM were provided with the growth media. P deprivation was achieved by washing cells twice in midlogarithmic growth phase with liquid TAP medium without P (TAP-P) and cells were resuspended at a density of 2.5 mg/ml Chlorophyll in TAP or TAP-P. Cell aliquots were collected for mRNA isolation 24 h after being transferred either to TAP or TAP-P medium.
Project description:RNA populations in Chlamydomonas reinhardtii Keywords: Highly parallel pyrosequencing Small RNAs were prepared from Chlamydomonas reinhardtii total extracts,ligated to a 3' adaptor and a 5' acceptor sequentially, and then RT-PCR amplified. PCR products were reamplified using a pair of 454 cloning primers and provided to 454 Life Sciences (Branford, CT) for sequencing. For technical details, see Tao Zhao, Guanglin Li, Shijun Mi, Shan Li, Gregory J. Hannon, Xiu-Jie Wang, and Yijun Qi. 2007. A Complex System of Small RNAs in the Unicellular Green Alga Chlamydomonas reinhardtii. Genes & Development
Project description:Chlamydomonas reinhardtii strain CC849 is seclected to sequence its transcriptome at different times under normal and stress conditions.Before we conducted RNA-sequencing at 0h (start point) and other seven timepoints(24hour, 48hour, 72hour, 96hour, 120hour, 168hour, 192hour) under normal and stress condition, respectively. These data are contained in GSE100763. Now, we add the RNA-seq data at 4hour, 12hour under normal and stress condition, respectively.