Location: Application Technology Research
Title: Cyanobacterial live cultures, cell extracts, and individual toxins all decrease photosynthesis in the terrestrial plants Lactuca sativa and Zea maysAuthor
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HECKATHORN, SCOTT - University Of Toledo |
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MULLER, CLARE - University Of Toledo |
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THOMAS, MICHAEL - University Of Toledo |
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VINING, EMILY - University Of Toledo |
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BIGIONI, SAMANTHA - University Of Toledo |
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ELSIE, CLAIR - University Of Toledo |
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FRANKLIN, J - University Of Toledo |
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MORRIS, JULIET - University Of Toledo |
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NEW, EMILY - University Of Toledo |
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Boldt, Jennifer |
Submitted to: Plants
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 11/8/2024 Publication Date: 11/13/2024 Citation: Heckathorn, S.A., Muller, C.T., Thomas, M.D., Vining, E.P., Bigioni, S., Elsie, C., Franklin, J.T., Morris, J.O., New, E.R., Boldt, J.K. 2024. Cyanobacterial live cultures, cell extracts, and individual toxins all decrease photosynthesis in the terrestrial plants Lactuca sativa and Zea mays. Plants. 13(22): Article 3190. https://doi.org/10.3390/plants13223190. DOI: https://doi.org/10.3390/plants13223190 Interpretive Summary: Many crops grown in fields, nurseries, or greenhouses are irrigated with freshwater from ponds and lakes. These freshwater sources may develop an overabundance of algae during the summer. Some algae produce toxins that make the water unsafe for humans and plants. This study identified that irrigating corn and lettuce plants with water containing intact algal cells, burst algal cells, or purified toxins all stunted plant growth. This suggests that filtering out algal cells from irrigation water will not sufficiently clean the water before applying it to a crop. The stunted plant growth occurred because the toxins targeted the process of photosynthesis. This enhanced understanding of what components of the irrigation water impact crop growth, and what systems in plants the toxins target, will guide the development of solutions that lessen the impact of algae-containing irrigation water on crop growth. Technical Abstract: Cyanobacterial harmful-algal blooms (cHABs) are increasing due to eutrophication and climate change, as is irrigation of crops with freshwater contaminated with cHAB toxins. A few studies, mostly in aquatic algae and plants, have investigated effects of cHAB toxins or cell extracts on various aspects of photosynthesis, with variable effects reported (negative-to-neutral-to-positive). We examined effects of cyanobacterial live cultures and cell extracts (Microcystis aeruginosa or Anabaena flos-aquae in nutrient solution) and individual cHAB toxins (anatoxin-a, ANA; beta-methyl-amino-L-alanine, BMAA; lipopolysaccharide, LPS; microcystin-LR, MC-LR) on photosynthesis in intact plants and leaf pieces in corn (Zea mays) and lettuce (Lactuca sativa). In intact plants grown in soil or hydroponically, overall net photosynthesis (Pn), but not Photosystem-II (PSII) electron-transport yield (FPSII), decreased when roots were exposed to algal culture (whether with intact cells, cells removed, or cells lysed and removed) or individual toxins in solution (especially ANA, which also decreased rubisco activity); algal culture also decreased leaf chlorophyll concentration. In contrast, FPSII decreased in leaf tissue vacuum-infiltrated with algal culture or the individual toxins, LPS and MC-LR, though only in illuminated (vs. dark-adapted) leaves, and only BMAA caused a small non-significant decrease in in vitro photosynthesis in thylakoids. Principal-component analysis indicated unique overall effects of algal culture and each toxin on photosynthesis. Hence, while cHAB toxins consistently impacted plant photosynthesis at ecologically-relevant concentrations, the effects varied depending on toxins and mode of exposure. |