Characterization and regulation of the Resistance-Nodulation-Cell Division-type multidrug efflux pumps MdtABC and MdtUVW from the fire blight pathogen Erwinia amylovora

被引:32
作者
Pletzer, Daniel [1 ]
Weingart, Helge [1 ]
机构
[1] Jacobs Univ Bremen, Sch Sci & Engn, D-28759 Bremen, Germany
来源
BMC MICROBIOLOGY | 2014年 / 14卷
关键词
Plant pathogen; Fire blight; Erwinia amylovora; Multidrug efflux; RND transporter; MdtABC; MdtUVW; BaeR; CpxR; SIGNAL-TRANSDUCTION SYSTEMS; ENVELOPE STRESS-RESPONSE; ESCHERICHIA-COLI; EXPRESSION ANALYSIS; CONDENSED TANNINS; SEQUENCE; OVEREXPRESSION; FLAVONOIDS; INDUCTION; VIRULENCE;
D O I
10.1186/1471-2180-14-185
中图分类号
Q93 [微生物学];
学科分类号
071005 ; 100705 ;
摘要
Background: The Gram-negative bacterium Erwinia amylovora is the causal agent of the devastating disease fire blight in rosaceous plants such as apple, pear, quince, raspberry, and cotoneaster. In order to survive and multiply in a host, microbes must be able to circumvent the toxic effects of antimicrobial plant compounds, such as flavonoids and tannins. E. amylovora uses multidrug efflux transporters that recognize and actively export toxic compounds out of the cells. Here, two heterotrimeric resistance-nodulation-cell division (RND)-type multidrug efflux pumps, MdtABC and MdtUVW, from E. amylovora were identified. These RND systems are unusual in that they contain two different RND proteins forming a functional pump. Results: To find the substrate specificities of the two efflux systems, we overexpressed the transporters in a hypersensitive mutant lacking the major RND pump AcrB. Both transporters mediated resistance to several flavonoids, fusidic acid and novobiocin. Additionally, MdtABC mediated resistance towards josamycin, bile salts and silver nitrate, and MdtUVW towards clotrimazole. The ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock was reduced. Quantitative RT-PCR analyses revealed that the expression of the transporter genes was induced during infection of apple rootstock. The polyphenolic plant compound tannin, as well as the heavy metal salt tungstate was found to induce the expression of mdtABC. Finally, the expression of the mdtABC genes was shown to be regulated by BaeR, the response regulator of the two component system BaeSR, a cell envelope stress response system that controls the adaptive responses to changes in the environment. Conclusions: The expression of MdtABC and MdtUVW is induced during growth of E. amylovora in planta. We identified the plant polyphenol tannin as inducer of mdtABC expression. The reduced ability of the mdtABC- and mdtUVW-deficient mutants to multiply in apple rootstock suggests that the efflux pumps are involved in resistance to plant antimicrobials, maybe including flavonoids, which were identified as substrates of both pumps. Furthermore, we found that the mdtABC operon belongs to the regulon of the two-component regulator BaeR suggesting a role of this RND transporter in the cell envelope stress response of E. amylovora.
引用
收藏
页数:15
相关论文
共 59 条
[11]   Antimicrobial activity of flavonoids [J].
Cushnie, TPT ;
Lamb, AJ .
INTERNATIONAL JOURNAL OF ANTIMICROBIAL AGENTS, 2005, 26 (05) :343-356
[12]   Iron and citrate export by a major facilitator superfamily pump regulates metabolism and stress resistance in Salmonella Typhimurium [J].
Frawley, Elaine R. ;
Crouch, Marie-Laure V. ;
Bingham-Ramos, Lacey K. ;
Robbins, Hannah F. ;
Wang, Wenliang ;
Wright, Gerard D. ;
Fang, Ferric C. .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2013, 110 (29) :12054-12059
[13]   Darwin v. 2.0: an interpreted computer language for the biosciences [J].
Gonnet, GH ;
Hallett, MT ;
Korostensky, C ;
Bernardin, L .
BIOINFORMATICS, 2000, 16 (02) :101-103
[14]  
Halbwirth H, 2003, Z NATURFORSCH C, V58, P765
[15]   β-Lactam resistance modulated by the overexpression of response regulators of two-component signal transduction systems in Escherichia coli [J].
Hirakawa, H ;
Nishino, K ;
Yamada, J ;
Hirata, T ;
Yamaguchi, A .
JOURNAL OF ANTIMICROBIAL CHEMOTHERAPY, 2003, 52 (04) :576-582
[16]   Indole induces the expression of multidrug exporter genes in Escherichia coli [J].
Hirakawa, H ;
Inazumi, Y ;
Masaki, T ;
Hirata, T ;
Yamaguchi, A .
MOLECULAR MICROBIOLOGY, 2005, 55 (04) :1113-1126
[17]   Comprehensive studies of drug resistance mediated by overexpression of response regulators of two-component signal transduction systems in Escherichia coli [J].
Hirakawa, H ;
Nishino, K ;
Hirata, T ;
Yamaguchi, A .
JOURNAL OF BACTERIOLOGY, 2003, 185 (06) :1851-1856
[18]   A broad-host-range Flp-FRT recombination system for site-specific excision of chromosomally-located DNA sequences:: application for isolation of unmarked Pseudomonas aeruginosa mutants [J].
Hoang, TT ;
Karkhoff-Schweizer, RR ;
Kutchma, AJ ;
Schweizer, HP .
GENE, 1998, 212 (01) :77-86
[19]   PCR fusion-based approach to create reporter gene constructs for expression analysis in transgenic C-elegans [J].
Hobert, O .
BIOTECHNIQUES, 2002, 32 (04) :728-730
[20]   Different Functions of MdtB and MdtC Subunits in the Heterotrimeric Efflux Transporter MdtB2C Complex of Escherichia coli [J].
Kim, Hong-Suk ;
Nikaido, Hiroshi .
BIOCHEMISTRY, 2012, 51 (20) :4188-4197