Regulation of Photosynthesis in Bloom-Forming Cyanobacteria with the Simplest β-Diketone

Abstract

Selective inhibition of photosynthesis is a fundamental strategy to solve the global challenge caused by harmful cyanobacterial blooms. However, there is a lack of specificity of the currently used cyanocides, because most of them act on cyanobacteria by generating nontargeted oxidative stress. Here, for the first time, we find that the simplest β-diketone, acetylacetone, is a promising specific cyanocide, which acts on Microcystis aeruginosa through targeted binding on bound iron species in the photosynthetic electron transport chain, rather than by oxidizing the components of the photosynthetic apparatus. The targeted binding approach outperforms the general oxidation mechanism in terms of specificity and eco-safety. Given the essential role of photosynthesis in both natural and artificial systems, this finding not only provides a unique solution for the selective control of cyanobacteria but also sheds new light on the ways to modulate photosynthesis.

Multi-stepwise charge transfer via MOF@MOF/TiO2 dual-heterojunction photocatalysts towards hydrogen evolution

“…1a). [14][15][16] By contrast to directly transferring from P680* to P700 + , the slight gradient difference of multi-stepwise energy bands can ensure a small interface resistance, thereby enabling the charge to transfer more easily and quickly. The multi-stepwise energy bands can also play a key role in deconcentrating the charge, thus further inhibiting the charge recombination.…”

Structure–Activity Relationship Study of Xanthoxyline and Related Small Methyl Ketone Herbicides

“…Diketones were also reported as plant growth inhibitors. 18 − 21 Even though their modes of action are likely to be complex, some diketones, such as benzobicyclon, are also HPPD inhibitors. 22 Monoketones, or compounds containing one ketonic carbonyl, are reported to exhibit weed-killing properties.…”

Acetylacetone Interferes with Carbon and Nitrogen Metabolism of Microcystis aeruginosa by Cutting Off the Electron Flow to Ferredoxin

“…In a recent work, the simplest β -diketone, acetylacetone (AA), was found as a specific cyanocide of freshwater cyanobacteria . Unlike most of the currently studied cyanocides that act on algae through generation of oxidative stress, AA inactivates Microcystis aeruginosa through a nonoxidative pathway . Such an inhibitory mechanism endows AA with better target selectivity.…”

“…Consequently, the use of AA as cyanocide can be considered as environmentally friendly and safe. On the basis of a combined analysis of photosynthetic oxygen-evolving activity, chlorophyll (Chl) a fluorescence induction kinetics, and differential protein analyses, it has been confirmed that AA interfered with the photosynthetic electron transport chain by selectively affecting the functionality of the nonheme iron (NHI) in photosystem II and the iron–sulfur clusters in ferredoxin (Fd) . In cyanobacteria, Fd not only plays a major role in reducing nicotinamide adenine dinucleotide phosphate (NADP + ) via ferredoxin-NADP reductase to complete the noncyclic (linear) electron transport chain but also serves as a reductant for a variety of other vital cellular processes, including photosynthetic assimilation of carbon/nitrogen/sulfur, cyclic photophosphorylation, regulation of several enzymes involved in the Calvin–Benson cycle, the cyclic electron flow around photosystem I, and the synthesis of Chls and amino acids. , Therefore, the interaction of AA with NHI and Fd of the photosynthetic electron transport chain may also affect other fundamental metabolic processes in cyanobacteria.…”