Project description:Liquid cultures of the unicellular green alga, Chlamydomonas reinhardtii were grown in media with 6 uM Mn (control) or 1000 uM Mn (experimental), and analyzed by RNA-Seq to identify genes that are differentially expressed in response to excess Mn.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The Streptophyta include unicellular and multicellular charophyte green algae and land plants. Colonization of the terrestrial habitat by land plants was a major evolutionary event that has transformed our planet. So far lack of genome information on unicellular charophyte algae hinders our understanding of the origin and the evolution from unicellular to multicellular life in Streptophyta. This work reports the high-quality reference genome and transcriptome of Mesostigma viride, a single-celled charophyte alga with a position at the base of Streptophyta. There are abundant segmental duplications and transposable elements in M. viride, which contribute to a relatively large genome with high gene content compared to other algae and early diverging land plants. This work identifies the origin of genetic tools that multicellular Streptophyta have inherited and key genetic innovations required for evolution of land plants from unicellular aquatic ancestors. The findings shed light on the age-old questions of the evolution of multicellularity and the origin of land plants.
Project description:The green alga Volvox carteri is a model organism for the development of multicellularity. It has a spherical shape with a complete division of labor between around 2000 somatic cells and 16 reproductive cells. When comparing Volvox with its unicellular relative Chlamydomonas rheinhardtii, one striking observation is the similarity in the protein coding genes [1]. Additionally, Baulcombe and colleagues showed that Chlamydomonas contains functional RNAi and miRNA machineries [2]. We deep sequenced small RNAs associated with one Argonaute protein of the female Volvox strain Vol6 during its vegetative growth phase. Using these data, we established a miRNA identification pipeline that takes into account plant miRNA feature in general and also uses parameters employed in finding miRNAs in Chlamydomonas. Other small RNAs that are functionally incorporated into Ago are characterized. 1. Prochnik, S.E., et al., Genomic analysis of organismal complexity in the multicellular green alga Volvox carteri. Science, 2010. 329(5988): p. 223-6. 2. Molnar, A., et al., miRNAs control gene expression in the single-cell alga Chlamydomonas reinhardtii. Nature, 2007. 447(7148): p. 1126-9. Examination of small RNAs bound to an Argonaute protein of Volvox carteri
Project description:Paramecium bursaria chlorella virus (PBCV-1), a member of the family Phycodnaviridae, is a large dsDNA, plaque-forming virus that infects the unicellular green alga Chlorella NC64A. The 331 kb PBCV-1 genome is predicted to encode 365 proteins and 11 tRNAs. To follow global transcription during PBCV-1 replication, a microarray containing 50-mer probes to the PBCV-1 365 protein-encoding genes (CDS) was constructed. Competitive hybridization experiments were conducted employing cDNA from poly A-containing RNA obtained from cells at seven time points after virus infection. The results led to the following conclusions: i) the PBCV-1 replication cycle is temporally programmed and regulated; ii) 360 (99%) of the arrayed PBCV-1 CDSs are expressed at some time in the virus life cycle in the laboratory; iii) 227 (62%) of the CDSs are expressed before virus DNA synthesis begins; iv) these 227 CDSs were grouped into two classes: 127 transcripts disappear prior to initiation of virus DNA synthesis (considered early) and 100 transcripts are still detected after virus DNA synthesis begins (considered early/late); v) 133 (36%) of the CDSs are expressed after virus DNA synthesis begins (considered late); vi) expression of most late CDSs is inhibited by adding the DNA replication inhibitor aphidicolin prior to virus infection. This study provides the first comprehensive evaluation of virus gene expression during the PBCV-1 lifecycle.
Project description:The understanding of molecular events occurring in green alga during CO2 deprivation, are still largely unknown. To well grasp its cellular metabolism, particularly the regulation of biosynthesis and degradation pathways of lipid, protein and carbohydrates, as well as the diverse trophic adaptation affecting carbon partitioning during the transition process, we sequenced the transcriptome (RNA-seq) in four time points to discover how transcriptional changes in C. pyrenoidosa modulate metabolic flux trends leading to intracellular components dynamic reassortment.