Project description:The aim of this experiment was to analyse the expression of two sets of genes identified as being putatively sporophyte-specific or gametophyte-specific by a suppressive subtraction hybridisation using cDNA from immature sporophytes and immature gametophytes of the Ectocarpus strain Esil32. The expression of these genes was analysed in the sporophyte and gametophyte generations of the life cycle (again using immature algae that had not yet produces zoidangia) and in the sporophyte generation of a mutant strain, immediate upright, that exhibits gametophyte-like characteristics during the sporophyte generation.
Project description:Bryophytes are the most basal of the extant land plants. A major feature of these plants is the biphasic alteration of generations between a dominant haploid gametophyte and a minor diploid sporophyte phase. To analyse the differences in the transcriptome of the early gametophyte (protonema) and early and mid-sporophyte phases of the moss Physcomitrella patens, microarray gene expression profiles were performed using dissected sporophyte tissue. Through further analysis the early and mid-sporophyte phases were compared.
Project description:Bryophytes are the most basal of the extant land plants. A major feature of these plants is the biphasic alteration of generations between a dominant haploid gametophyte and a minor diploid sporophyte phase. To analyse the differences in the transcriptome of the early gametophyte (protonema) and early and mid-sporophyte phases of the moss Physcomitrella patens, microarray gene expression profiles were performed using dissected sporophyte tissue. Through further analysis the early and mid-sporophyte phases were compared. RNA isolated from the Gametophytic protonemal tissue was hybridised to six microarrays. Each microarray was hybridised with RNA from a separate biological replicate. Three of these microarrays were co-hybridised with RNA isolated from early sporophytes. With the third gametophyte biological replicate and early sporophyte replicate a dye swap was carried out. The remaining three microarrays hybridised with RNA from the gametophytes were co-hybridised with RNA from mid-sporophytic tissue. A dye swap was carried out on the sixth gametophyte replicate and third mid-sporophyte replicate.To meet the quality requirements for the microarray experiment, at least 400 sporophytes were used per extraction. Three or four RNA extracts were then pooled for further precipitation to maximise purity and concentration. Up to 1600 sporophytes were harvested to prepare sufficient RNA for each microarray replicate. In bioinformatic analysis the channels were split into individual channels and the early and mid-sporophyte were compared.
Project description:The red seaweed, Asparagopsis taxiformis, is a promising ruminant feed-additive with significant anti-methanogenic properties, which could provide a global solution to climate-change. Emerging genomics in this species has provided a strong foundation for in-depth molecular investigations, including proteomics. Here, we investigated the A. taxiformis (L6) proteome of sporophyte and gametophyte (male and female), using soluble and insoluble extraction methods followed by mass spectrometry. A combined total of 741 and 2007 unique non-redundant proteins were identified using genome-derived and transcriptome-derived databases, respectively. Genome-derived proteins were used for further analysis including a relatively large proportion of proteins that were annotated as ion binding proteins (i.e. iron, zinc, manganese, potassium and copper), which may play a role in heavy metal bioremediation. In addition, we identified 44 photosynthesis-related proteins (e.g. phycobilisomes, photosystem I, photosystem II and ATPase) and 58 stress-related proteins (e.g. heat shock proteins and vanadium-dependent haloperoxidases). Forty proteins were predicted to be secreted, supporting a role for them in extracellular activities such as mucilage development and defence. Two Gal-2,6-Sulfurylases II proteins are likely necessary for carrageenan biosynthesis, as well as development of reproductive-associated structures. These findings provide a comprehensive overview of expressed proteins in A. taxiformis (L6) at two different life stages, highlighting the potential of proteomic approaches and warrant further studies for understanding protein functions.
Project description:The flowering plant life cycle consists of alternating haploid (gametophyte) and diploid (sporophyte) generations, where the sporophytic generation begins with fertilization of haploid gametes. In Arabidopsis, genome-wide DNA demethylation is required for normal development, catalyzed by the DEMETER (DME) DNA demethylase in the gamete companion cells of male and female gametophytes. In the sporophyte, postembryonic growth and development are largely dependent on the activity of numerous stem cell niches, or meristems. Analyzing Arabidopsis plants homozygous for a loss-of-function dme-2 allele, we show that DME influences many aspects of sporophytic growth and development. dme-2 mutants exhibited delayed seed germination, variable root hair growth, aberrant cellular proliferation and differentiation followed by enhanced de novo shoot formation, dysregulation of root quiescence and stomatal precursor cells, and inflorescence meristem (IM) resurrection. We also show that sporophytic DME activity exerts a profound effect on the transcriptome of developing Arabidopsis plants, including discrete groups of regulatory genes that are misregulated in dme-2 mutant tissues, allowing us to potentially link phenotypes to changes in specific gene expression pathways. These results show that DME plays a key role in sporophytic development and suggest that DME-mediated active DNA demethylation may be involved in the maintenance of stem cell activities during the sporophytic life cycle in Arabidopsis.