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Production of indole-3-acetic acid via the indole-3-acetamide pathway in the plant-beneficial bacterium Pseudomonas chlororaphis O6 is inhibited by ZnO nanoparticles but enhanced by CuO nanoparticles.
Appl Environ Microbiol. 2012 Mar; 78(5):1404-10.AE

Abstract

The beneficial bacterium Pseudomonas chlororaphis O6 produces indole-3-acetic acid (IAA), a plant growth regulator. However, the pathway involved in IAA production in this bacterium has not been reported. In this paper we describe the involvement of the indole-3-acetamide (IAM) pathway in IAA production in P. chlororaphis O6 and the effects of CuO and ZnO nanoparticles (NPs). Sublethal levels of CuO and ZnO NPs differentially affected the levels of IAA secreted in medium containing tryptophan as the precursor. After 15 h of growth, CuO NP-exposed cells had metabolized more tryptophan than the control and ZnO NP-challenged cells. The CuO NP-treated cells produced higher IAA levels than control cultures lacking NPs. In contrast, ZnO NPs inhibited IAA production. Mixing of CuO and ZnO NPs resulted in an intermediate level of IAA production relative to the levels in the separate CuO and ZnO NP treatments. The effect of CuO NPs on IAA levels could be duplicated by ions at the concentrations released from the NPs. However, ion release did not account for the inhibition caused by the ZnO NPs. The mechanism underlying changes in IAA levels cannot be accounted for by effects on transcript accumulation from genes encoding a tryptophan permease or the IAM hydrolase in 15-h cultures. These findings raise the issue of whether sublethal doses of NPs would modify the beneficial effects of association between plants and bacteria.

Authors+Show Affiliations

Department of Biological Engineering, Utah State University, Logan, UT, USA. cdimkpa@usu.eduNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

22210218

Citation

Dimkpa, Christian O., et al. "Production of Indole-3-acetic Acid Via the Indole-3-acetamide Pathway in the Plant-beneficial Bacterium Pseudomonas Chlororaphis O6 Is Inhibited By ZnO Nanoparticles but Enhanced By CuO Nanoparticles." Applied and Environmental Microbiology, vol. 78, no. 5, 2012, pp. 1404-10.
Dimkpa CO, Zeng J, McLean JE, et al. Production of indole-3-acetic acid via the indole-3-acetamide pathway in the plant-beneficial bacterium Pseudomonas chlororaphis O6 is inhibited by ZnO nanoparticles but enhanced by CuO nanoparticles. Appl Environ Microbiol. 2012;78(5):1404-10.
Dimkpa, C. O., Zeng, J., McLean, J. E., Britt, D. W., Zhan, J., & Anderson, A. J. (2012). Production of indole-3-acetic acid via the indole-3-acetamide pathway in the plant-beneficial bacterium Pseudomonas chlororaphis O6 is inhibited by ZnO nanoparticles but enhanced by CuO nanoparticles. Applied and Environmental Microbiology, 78(5), 1404-10. https://doi.org/10.1128/AEM.07424-11
Dimkpa CO, et al. Production of Indole-3-acetic Acid Via the Indole-3-acetamide Pathway in the Plant-beneficial Bacterium Pseudomonas Chlororaphis O6 Is Inhibited By ZnO Nanoparticles but Enhanced By CuO Nanoparticles. Appl Environ Microbiol. 2012;78(5):1404-10. PubMed PMID: 22210218.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Production of indole-3-acetic acid via the indole-3-acetamide pathway in the plant-beneficial bacterium Pseudomonas chlororaphis O6 is inhibited by ZnO nanoparticles but enhanced by CuO nanoparticles. AU - Dimkpa,Christian O, AU - Zeng,Jia, AU - McLean,Joan E, AU - Britt,David W, AU - Zhan,Jixun, AU - Anderson,Anne J, Y1 - 2011/12/30/ PY - 2012/1/3/entrez PY - 2012/1/3/pubmed PY - 2012/5/9/medline SP - 1404 EP - 10 JF - Applied and environmental microbiology JO - Appl Environ Microbiol VL - 78 IS - 5 N2 - The beneficial bacterium Pseudomonas chlororaphis O6 produces indole-3-acetic acid (IAA), a plant growth regulator. However, the pathway involved in IAA production in this bacterium has not been reported. In this paper we describe the involvement of the indole-3-acetamide (IAM) pathway in IAA production in P. chlororaphis O6 and the effects of CuO and ZnO nanoparticles (NPs). Sublethal levels of CuO and ZnO NPs differentially affected the levels of IAA secreted in medium containing tryptophan as the precursor. After 15 h of growth, CuO NP-exposed cells had metabolized more tryptophan than the control and ZnO NP-challenged cells. The CuO NP-treated cells produced higher IAA levels than control cultures lacking NPs. In contrast, ZnO NPs inhibited IAA production. Mixing of CuO and ZnO NPs resulted in an intermediate level of IAA production relative to the levels in the separate CuO and ZnO NP treatments. The effect of CuO NPs on IAA levels could be duplicated by ions at the concentrations released from the NPs. However, ion release did not account for the inhibition caused by the ZnO NPs. The mechanism underlying changes in IAA levels cannot be accounted for by effects on transcript accumulation from genes encoding a tryptophan permease or the IAM hydrolase in 15-h cultures. These findings raise the issue of whether sublethal doses of NPs would modify the beneficial effects of association between plants and bacteria. SN - 1098-5336 UR - https://www.unboundmedicine.com/medline/citation/22210218/Production_of_indole_3_acetic_acid_via_the_indole_3_acetamide_pathway_in_the_plant_beneficial_bacterium_Pseudomonas_chlororaphis_O6_is_inhibited_by_ZnO_nanoparticles_but_enhanced_by_CuO_nanoparticles_ L2 - http://aem.asm.org/cgi/pmidlookup?view=long&pmid=22210218 DB - PRIME DP - Unbound Medicine ER -