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Effect of Different Light Intensities on Freshwater Red Algae Batrachospermum gelatinosum: A Transcriptomic Approach

Tiwari, Sunil
http://rave.ohiolink.edu/etdc/view?acc_num=ohiou159671675380422

Abstract Details

2020, Master of Science (MS), Ohio University, Plant Biology (Arts and Sciences).
Freshwater red algae are common primary producers in streams and rivers throughout the world. Physiological studies of these algae have shown that they are shade-adapted and can acclimate to various light conditions. Only two studies on gene regulation have been conducted in freshwater red algae to elucidate the effect of light on photosynthesis. Batrachospermum gelatinosum commonly inhabits running waters with varying light regimes in North America and Europe making this taxon a good candidate for study. The purpose of this research was to examine gene expression under light levels representing initial saturation, saturation and photoinhibition. Field collected gametophytes were acclimated to 265 μmol photon m-2 s-1 and then subjected to 75 μmol photon m-2 s-1 (low), 265 μmol photon m-2 s-1 (medium) and 600 μmol photon m-2 s-1 (high) for 72 hours. RNA was extracted in quadruplicate for each light level and sequenced on HiSeq2500 platform. All 12 replicates were used for de-novo assembly of the transcriptome. In the assembly process, only contigs identified as Rhodophyta were used, which represents a conservative approach to ensure that all possible contaminants such as epiphytes were removed for the differential gene expression analyses. Differential expression analysis between the Low vs Medium and High vs Medium, revealed the downregulation of chlorophyll synthesis pathway in Low light. The carbohydrate metabolism was downregulated in High light, while there was evidence of starch accumulation in Low light. Photoprotective mechanisms were evident in High light indicated by the upregulation of tocopherol and phylloquinone biosynthetic pathway. The transcription/translation process along with the protein translocation in endoplasmic reticulum were downregulated in High light while the genes involved in unfolded protein response and misfolded protein degradation were upregulated. Although it was expected that genes of the light harvesting cap and photosynthesis would be differentially expressed, little change was observed and may be due to physiological changes rather than changes at the molecular level in response to this short-term study. It was observed that chlorophyll synthesis, carbohydrate metabolism and photoprotective mechanisms were affected.
Morgan Vis, Dr (Advisor)
Sarah Wyatt , Dr (Committee Member)
David Rosenthal, Dr (Committee Member)
87 p.
Plant Biology
Photoinhibition; Photoprotection; Photoadaptation

Recommended Citations

Citations

  • Tiwari, S. (2020). Effect of Different Light Intensities on Freshwater Red Algae Batrachospermum gelatinosum: A Transcriptomic Approach [Master's thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou159671675380422

    APA Style (7th edition)

  • Tiwari, Sunil. Effect of Different Light Intensities on Freshwater Red Algae Batrachospermum gelatinosum: A Transcriptomic Approach. 2020. Ohio University, Master's thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ohiou159671675380422.

    MLA Style (8th edition)

  • Tiwari, Sunil. "Effect of Different Light Intensities on Freshwater Red Algae Batrachospermum gelatinosum: A Transcriptomic Approach." Master's thesis, Ohio University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou159671675380422

    Chicago Manual of Style (17th edition)

ohiou159671675380422
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This open access ETD is published by Ohio University and OhioLINK.