Impacts of hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor (mesotrione) on photosynthetic processes in Chlamydomonas reinhardtii. (January 2019)

• Record Type: Journal Article
• Authors: Xu, Kui; Racine, Francis; He, Zhili; Juneau, Philippe
• Is Part Of: Environmental pollution. Volume 244(2019)
• Page Start: 295
• Page End: 303
• Publication Date: 2019-01
• Subjects: Chlamydomonas reinhardtii -- HPPD inhibitor -- Mesotrione -- Photosynthetic energy dissipation -- Photoinhibition recovery; ABS absorbance -- Car:Chl-a carotenoids to Chl-a pigment ratio -- Chl Chlorophyll -- Cyt b6f cytochrome b6f complex -- DI0 dissipation -- FPSII/FPSI 77k-fluorescence emission ratio of photosystem II and photosystem I -- HL high light intensity treatment (1100 μE/m2/s for 75 min) -- HPLC high performance liquid chromatography -- HPPD hydroxyphenylpyruvate dioxygenase -- HSM high-salt medium -- LHCII light harvesting complex of photosystem II -- LL low light intensity (100 μE/m2/s) -- NPQ non-photochemical fluorescence quenching -- PDS phytoene desaturase -- PQ and PQH2 plastoquinone and plastoquinol -- PSI and PSII photosystem I and photosystem II -- QA and QB primary and secondary electron acceptor of PS II -- qE energy-dependant fluorescence quenching -- qI photoinhibitory quenching -- qN non-photochemical quenching -- qP photochemical quenching -- qPQ quenching of the PSII fluorescence associated with oxidized plastoquinones -- qT quenching related to state transitions -- RC reaction centre -- ROS reactive oxygen species -- UQFrel relative unquenched fluorescence -- [Z/(Z+A+V)] de-epoxidation of violaxanthin -- ΔpH transthylakoid pH gradient -- Φ'M operational PSII quantum yield -- ΦM maximal PSII quantum yield; Pollution -- Periodicals; Pollution -- Environmental aspects -- Periodicals; Environmental Pollution -- Periodicals; Pollution -- Périodiques; Pollution -- Aspect de l'environnement -- Périodiques; Pollution -- Effets physiologiques -- Périodiques; Pollution; Pollution -- Environmental aspects; Periodicals; Electronic journals; 363.73
• DOI: 10.1016/j.envpol.2018.09.121
• Languages: English
• ISSNs: 0269-7491

Abstract

Abstract: Mesotrione, an herbicide increasingly found in aquatic systems due to its increased application frequency in corn fields, is an inhibitor of the p-hydroxyphenylpyruvate dioxygenase (HPPD), a key enzyme for plastoquinone-9, α-tocopherol and indirectly for carotenoid biosynthesis. The direct effect of mesotrione on plastoquinone-9 and α-tocopherol synthesis and their degradation rates are well documented, but few information exists on its action on photosynthetic processes under various light intensities. We therefore investigated the photosynthetic activity, energy dissipation processes, pigment composition and α-tocopherol content when Chlamydomonas reinhardtii were exposed to mesotrione for 24 h under low light condition and then the impacts of HL treatment (75 min) were also investigated. Under low light growth conditions, mesotrione did not induce PSII photoinhihition, while substantially decreased Car:Chl- a ratio, maximal energy-dependant quenching and state 1 to state 2 transition. Under high light conditions (HL), PSII activity was highly decreased in presence of mesotrione, and the non-photochemical energy dissipation processes were drastically affected in these conditions compared to the HL treatment alone. Mesotrinone also prevent the complete recovery of PSII damage caused by HL. Light condition seems therefore to be a non-negligible factor modulating mesotrione toxicity, and this has an obvious importance in agricultural waterbodies where phytoplankton is subjected to fluctuating light intensities. Graphical abstract: Image 1 Highlights: Mesotrione impacts on Chlamydomonas reinhardtii under two light intensities were studied. Mesotrione affects indirectly carotenoid biosynthesis and chlorophyll content. High light amplifies the effects of mesotrione on energy dissipation and photosynthesis. Mesotrione prevents the complete recovery of PSII photoinhibition. These results have implications for algae living in fluctuating light environments. Abstract : Mesotrione has synergistic effects with high light on pigment content and PSII activity and prevents complete recovery of photoinhibited algae.