Analysis of sublethal arsenic toxicity to Ceratophyllum demersum: subcellular distribution of arsenic and inhibition of chlorophyll biosynthesis

0465037 - MBÚ 2017 RIV GB eng J - Článek v odborném periodiku
Mishra, S. - Alfred, M. - Sobotka, Roman - Andresen, E. - Falkenberg, G. - Küpper, Hendrik
Analysis of sublethal arsenic toxicity to Ceratophyllum demersum: subcellular distribution of arsenic and inhibition of chlorophyll biosynthesis.
Journal of Experimental Botany. Roč. 67, č. 15 (2016), s. 4639-4646. ISSN 0022-0957. E-ISSN 1460-2431
Grant CEP: GA ČR GBP501/12/G055; GA MŠMT(CZ) LO1416
Institucionální podpora: RVO:61388971 ; RVO:60077344
Klíčová slova: arsenic toxicity * chlorophyll biosynthesis * subcellular distribution of arsenic * synchrotron micro-X-ray fluorescence
Kód oboru RIV: EE - Mikrobiologie, virologie; CE - Biochemie (BC-A)
Impakt faktor: 5.830, rok: 2016

At sublethal toxic concentrations, arsenic is predominantly localized in the nucleus but is already able to inhibit chlorophyll biosynthesis upstream of coproporphyrinogen III.Arsenic (As) pollution is a serious concern worldwide. Recent studies under environmentally relevant conditions revealed that, in the aquatic plant Ceratophyllum demersum, pigments are the first observable target of toxicity, prior to any effect on photosynthetic parameters or to oxidative stress. Lethal toxicity was initiated by a change of As species and their distribution pattern in various tissues. Here, the localization of As was investigated at the subcellular level through X-ray fluorescence using a submicron beam and a Maia detector. Further, it was possible to obtain useful tissue structural information from the ratio of the tomogram of photon flux behind the sample to the tomogram of Compton scattering. The micro-X-ray fluorescence tomograms showed that As predominantly accumulated in the nucleus of the epidermal cells in young mature leaves exposed to sublethal 1 A mu M As. This suggests that As may exert toxic effects in the nucleus, for example, by interfering with nucleic acid synthesis by replacing phosphorous with As. At higher cellular concentrations, As was mainly stored in the vacuole, particularly in mature leaves. An analysis of precursors of chlorophyll and degradation metabolites revealed that the observed decrease in chlorophyll concentration was associated with hindered biosynthesis, and was not due to degradation. Coproporphyrinogen III could not be detected after exposure to only 0.5 A mu M As.
Trvalý link: http://hdl.handle.net/11104/0264324