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Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis.
Ecotoxicol Environ Saf. 2020 Jul 03; 202:110856.EE

Abstract

To explore the mechanisms underlying the action of the heavy metals Cd and Zn on the photosynthetic function of plant leaves, the effects of 100 μmol L-1 Cd and 200 μmol L-1 Zn stress (the exposure concentrations of Cd and Zn in the culture medium were 2.24 mg kg-1 and 5.36 mg kg-1) on the chlorophyll and carotenoid contents as well as the photosynthetic function of tobacco leaves (Long Jiang 911) were studied. The key proteins in these physiological processes were quantitatively analyzed using a TMT-based proteomics approach. Cd stress was found to inhibit the expression of key enzymes during chlorophyll synthesis in leaves, resulting in a decrease of the Chl content. However, Zn stress did not significantly influence the chlorophyll content. Leaves adapted to Zn stress by upregulating CAO expression and increase the Chl b content. Although the Car content in leaves did not significantly change under either Cd or Zn stress, the expressions of ZE and VDE during Car metabolism decreased significantly under Cd stress. This was accompanied by damages to the xanthophyll cycle and the NPQ-dependent energy dissipation mechanism. In contrast, under Zn stress, leaves adapted to Zn stress by increasing the expression of VDE, thus improving NPQ. Under Cd stress, the expressions of three sets of proteins were significantly down-regulated, including PSII donor-side proteins (PPD3, PPD6, OEE1, OEE2-1, OEE2-2, OEE2-3, and OEE3-2), receptor-side proteins (D1, D2, CP43, CP47, Cyt b559α, Cyt b559β, PsbL, PsbQ, PsbR, Psb27-H1, and Psb28), and core proteins of the PSI reaction center (psaA, psaB, psaC, psaD, psaE-A, PsaE-B, psaF, psaG, psaH-1, psaK, psaL, psaN, and psaOL). In comparison, only eight of the above proteins (PPD6, OEE3-2, PsbL, PsbQ, Psb27-H1, psaL, and psaOL) were significantly down-regulated by Zn stress. Under Cd stress, both the donor side and the receptor side of PSII were damaged, and PSII and PSI experienced severe photoinhibition. However, Zn stress did not decrease either PSII or PSI activities in tobacco leaves. In addition, the expression of electron transport-related proteins (cytb6/f complex, PC, Fd, and FNR), ATPase subunits, Rubisco subunits, and RCA decreased significantly in leaves under Cd stress. However, no significant changes were observed in any of these proteins under Zn stress. Although Cd stress was found to up-regulate the expressions of PGRL1A and PGRL1B and induce an increase of PGR5/PGRL1-CEF in tobacco leaves, NDH-CEF was significantly inhibited. Under Zn stress, the expressions of ndhH and PGRL1A in leaves were significantly up-regulated, but there were no significant changes in either NDH-CEF or PGR5/PGRL-CEF. Under Cd stress, the expressions of proteins related to Fd-dependent nitrogen metabolism and reactive oxygen species (ROS) scavenging processes (e.g., FTR, Fd-NiR, and Fd-GOGAT) were significantly down-regulated in leaves. However, no significant changes of any of the above proteins were identified under Zn stress. In summary, Cd stress could inhibit the synthesis of chlorophyll in tobacco leaves, significantly down-regulate the expressions of photosynthesis-related proteins or subunits, and suppress both the xanthophyll cycle and NDH-CEF process. The expressions of proteins related to the Fd-dependent nitrogen metabolism and ROS scavenging were also significantly down-regulated, which blocked the photosynthetic electron transport, thus resulting in severe photoinhibition of both PSII and PSI. However, Zn stress had little effect on the photosynthetic function of tobacco leaves.

Authors+Show Affiliations

College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China; Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China.College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China.College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China.College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China.Mudanjiang Tobacco Science Research Institute, Mudanjiang, Heilongjiang, China.Mudanjiang Tobacco Science Research Institute, Mudanjiang, Heilongjiang, China.College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China.Natural Resources and Ecology Institute, Heilongjiang Sciences Academy, Harbin, Heilongjiang, China.College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China. Electronic address: yangwei@neau.edu.cn.Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China. Electronic address: sungy@nefu.edu.cn.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

32629202

Citation

Zhang, Huihui, et al. "Toxic Effects of Heavy Metal Cd and Zn On Chlorophyll, Carotenoid Metabolism and Photosynthetic Function in Tobacco Leaves Revealed By Physiological and Proteomics Analysis." Ecotoxicology and Environmental Safety, vol. 202, 2020, p. 110856.
Zhang H, Xu Z, Guo K, et al. Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis. Ecotoxicol Environ Saf. 2020;202:110856.
Zhang, H., Xu, Z., Guo, K., Huo, Y., He, G., Sun, H., Guan, Y., Xu, N., Yang, W., & Sun, G. (2020). Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis. Ecotoxicology and Environmental Safety, 202, 110856. https://doi.org/10.1016/j.ecoenv.2020.110856
Zhang H, et al. Toxic Effects of Heavy Metal Cd and Zn On Chlorophyll, Carotenoid Metabolism and Photosynthetic Function in Tobacco Leaves Revealed By Physiological and Proteomics Analysis. Ecotoxicol Environ Saf. 2020 Jul 3;202:110856. PubMed PMID: 32629202.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis. AU - Zhang,Huihui, AU - Xu,Zisong, AU - Guo,Kaiwen, AU - Huo,Yuze, AU - He,Guoqiang, AU - Sun,Hongwei, AU - Guan,Yupeng, AU - Xu,Nan, AU - Yang,Wei, AU - Sun,Guangyu, Y1 - 2020/07/03/ PY - 2020/03/30/received PY - 2020/05/29/revised PY - 2020/06/01/accepted PY - 2020/7/7/pubmed PY - 2020/7/7/medline PY - 2020/7/7/entrez KW - Cd stress KW - Photoprotective mechanism KW - Photosynthetic KW - Proteomics KW - Tobacco KW - Zn stress SP - 110856 EP - 110856 JF - Ecotoxicology and environmental safety JO - Ecotoxicol. Environ. Saf. VL - 202 N2 - To explore the mechanisms underlying the action of the heavy metals Cd and Zn on the photosynthetic function of plant leaves, the effects of 100 μmol L-1 Cd and 200 μmol L-1 Zn stress (the exposure concentrations of Cd and Zn in the culture medium were 2.24 mg kg-1 and 5.36 mg kg-1) on the chlorophyll and carotenoid contents as well as the photosynthetic function of tobacco leaves (Long Jiang 911) were studied. The key proteins in these physiological processes were quantitatively analyzed using a TMT-based proteomics approach. Cd stress was found to inhibit the expression of key enzymes during chlorophyll synthesis in leaves, resulting in a decrease of the Chl content. However, Zn stress did not significantly influence the chlorophyll content. Leaves adapted to Zn stress by upregulating CAO expression and increase the Chl b content. Although the Car content in leaves did not significantly change under either Cd or Zn stress, the expressions of ZE and VDE during Car metabolism decreased significantly under Cd stress. This was accompanied by damages to the xanthophyll cycle and the NPQ-dependent energy dissipation mechanism. In contrast, under Zn stress, leaves adapted to Zn stress by increasing the expression of VDE, thus improving NPQ. Under Cd stress, the expressions of three sets of proteins were significantly down-regulated, including PSII donor-side proteins (PPD3, PPD6, OEE1, OEE2-1, OEE2-2, OEE2-3, and OEE3-2), receptor-side proteins (D1, D2, CP43, CP47, Cyt b559α, Cyt b559β, PsbL, PsbQ, PsbR, Psb27-H1, and Psb28), and core proteins of the PSI reaction center (psaA, psaB, psaC, psaD, psaE-A, PsaE-B, psaF, psaG, psaH-1, psaK, psaL, psaN, and psaOL). In comparison, only eight of the above proteins (PPD6, OEE3-2, PsbL, PsbQ, Psb27-H1, psaL, and psaOL) were significantly down-regulated by Zn stress. Under Cd stress, both the donor side and the receptor side of PSII were damaged, and PSII and PSI experienced severe photoinhibition. However, Zn stress did not decrease either PSII or PSI activities in tobacco leaves. In addition, the expression of electron transport-related proteins (cytb6/f complex, PC, Fd, and FNR), ATPase subunits, Rubisco subunits, and RCA decreased significantly in leaves under Cd stress. However, no significant changes were observed in any of these proteins under Zn stress. Although Cd stress was found to up-regulate the expressions of PGRL1A and PGRL1B and induce an increase of PGR5/PGRL1-CEF in tobacco leaves, NDH-CEF was significantly inhibited. Under Zn stress, the expressions of ndhH and PGRL1A in leaves were significantly up-regulated, but there were no significant changes in either NDH-CEF or PGR5/PGRL-CEF. Under Cd stress, the expressions of proteins related to Fd-dependent nitrogen metabolism and reactive oxygen species (ROS) scavenging processes (e.g., FTR, Fd-NiR, and Fd-GOGAT) were significantly down-regulated in leaves. However, no significant changes of any of the above proteins were identified under Zn stress. In summary, Cd stress could inhibit the synthesis of chlorophyll in tobacco leaves, significantly down-regulate the expressions of photosynthesis-related proteins or subunits, and suppress both the xanthophyll cycle and NDH-CEF process. The expressions of proteins related to the Fd-dependent nitrogen metabolism and ROS scavenging were also significantly down-regulated, which blocked the photosynthetic electron transport, thus resulting in severe photoinhibition of both PSII and PSI. However, Zn stress had little effect on the photosynthetic function of tobacco leaves. SN - 1090-2414 UR - https://www.unboundmedicine.com/medline/citation/32629202/Toxic_effects_of_heavy_metal_Cd_and_Zn_on_chlorophyll,_carotenoid_metabolism_and_photosynthetic_function_in_tobacco_leaves_revealed_by_physiological_and_proteomics_analysis L2 - https://linkinghub.elsevier.com/retrieve/pii/S0147-6513(20)30695-3 DB - PRIME DP - Unbound Medicine ER -
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