Project description:Green hydra (Hydra viridissima) harbors endosymbiotic Chlorella and have established a mutual relation. To identify the host hydra genes involved in the specific symbiotic relationship, transcriptomes of intact H. viridissima colonized with symbiotic Chlorella strain A99, aposymbiotic H.viridissima and H. viridissima artificially infected with other symbiotic Chlorella were compared by microarray analysis. The results indicated that genes involved in nutrition supply to Chlorella were upregulated in the symbiotic hydra. In addition, it was induced by supply of photosynthates from the symbiont to the host, suggesting cooperative metabolic interaction between the host and the symbiotic algae.
Project description:By applying Illumina Novaseq 6000, Chlorella sp. TLD6B cells of the control group on day zero and 18, as well as under low salt stress (NaCl1) and under high salt stress (NaCl2) on day 18 were selected for transcriptome sequencing analysis. Meanwhile, 0.05 g/mL ( PEG1) and 0.1 g/mL PEG-6000 (medium for drought stress, PEG2 ) were used to prepare the drought-stressed Chlorella sp. TLD6B cells. Each treatment had two replicates. Clean data were filtered after the removal of adapters, poly-N strands, and low-quality reads. There were no reference genomes for Chlorella sp. TLD6B, and de novo assembly for clean reads was performed by using Trinity. The sequences were compared with databases such as NR, NT, Swiss-Pro, GO, KEGG, PFAM, and KOG using Blast X (e-value ≤ 10-5). The GO annotation of unigenes was obtained using BLAST2GO. FPKM method was used for the analysis of gene expression levels (Trapnell et al., 2010). Out of six samples, a total of 963,078,184 raw reads were generated. A total of 947,225,244 clean reads were obtained based on the base quality score and read length. Meanwhile, the GC percentage in clean reads reached nearly 66.0%, with Q20 being above 96%. A total of 219,577 transcripts with an average length of 1,394 bp were obtained. In total, 155,503 non-redundant unigenes were assembled for the following analyses. The length of the unigenes ranged from 200 bp to 23,825 bp, with an average length of 1,842 bp. Under different salt stress, verification had been conducted with qRT-PCR on nine unigenes of different pathways, which were related to lipid metabolism. The detection results by qRT-PCR were highly correlated with RNA-Seq results (r = 0.890, r2 = 0.791), which indicated that the RNA-Seq data of Chlorella sp. TLD6B under salt stress were accurate and reliable. Our study represents the first detailed analysis of Chlorella sp. TLD6B under salt stress transcriptomes. Hierarchical clustering of differentially expressed genes uncovered several currently uncharacterized genes that may contribute to the function about lipid accumulation of Chlorella sp. TLD6B under salt stress.
Project description:Micractinium conductrix SAG 241.80 secretes sugars (especially maltose) at pH 5.7 while very little sugar is found at pH 7.6. Another algae, Chlorella sorokiniana does not secrete sugars at either pH. We evaluated the transcriptional profiles of both species of algae at pH 5.7 and 7.6 to make comparisons in the regulation of potential genes involved in these pathways.
Project description:Purpose: The purpose of this study are to identify the miRNA involved in regulating the production of metabolites in Chlorella sorokiniana and Chlorella zofingiensis under normal and stress-induced condition through RNA-sequencing technique. Methods: miRNA transcriptome profile from normal and stress sample of C. sorokiniana and C. zofingiensis were generated, in triplicate, using Illumina Miseq. The sequence reads that passed quality filters were analysed using CLC genomic workbench and OmiRas. Results: The known and predicted novel miRNAs were identified. Although most of the identified miRNAs were not functionally determined, this study suggests that they were species-specific, which may have roles in regulating genes during stress related condition.
