Pathogen-induced expression of a cecropin A-melittin antimicrobial peptide gene confers antifungal resistance in transgenic tobacco

Abstract Background: WRKY transcription factors (TFs) play vital roles in plant growth and development, secondary metabolite synthesis, and response to biotic and abiotic stresses. In a previous transcriptome sequencing analysis of Lilium regale Wilson, we identified multiple WRKY TFs that respond to exogenous methyl jasmonate treatment and lily Fusarium wilt (Fusarium oxysporum).Results: In the present study, the WRKY TF LrWRKY3 was further analyzed to reveal its function in defense response to F. oxysporum. The LrWRKY3 protein was localized in the plant cell nucleus, and LrWRKY3 transgenic tobacco lines showed higher resistance to F. oxysporum compared with wild-type (WT) tobacco. In addition, some genes related to jasmonic acid (JA) biosynthesis, salicylic acid (SA) signal transduction, and disease resistance had higher transcriptional levels in the LrWRKY3 transgenic tobacco lines than in the WT. On the contrary, L. regale scales transiently expressing LrWRKY3 RNA interference fragments showed higher sensitivity to F. oxysporum infection. Moreover, a F. oxysporum-induced defensin gene, Def1, was isolated from L. regale, and the recombinant protein LrDef1 isolated and purified from Escherichia coli possessed antifungal activity to several phytopathogens, including F. oxysporum. Furthermore, co-expression of LrWRKY3 and the LrDef1 promoter in tobacco evidently up-regulated the expression activity of the LrDef1 promoter.Conclusions: These results clearly indicate that LrWRKY3 is an important positive regulator in response to F. oxysporum infection, and one of its targets is the antimicrobial peptide gene LrDef1.

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Paneth cells of the human small intestine express an antimicrobial peptide gene

Journal of Biological Chemistry ◽

10.1016/s0021-9258(18)50079-x ◽

1992 ◽

Vol 267 (32) ◽

pp. 23216-23225

Author(s):

D.E. Jones ◽

C.L. Bevins

Keyword(s):

Small Intestine ◽

Antimicrobial Peptide ◽

Paneth Cells ◽

Human Small Intestine ◽

Peptide Gene

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Induced Expression of Sarcotoxin IA Enhanced Host Resistance Against Both Bacterial and Fungal Pathogens in Transgenic Tobacco

Molecular Plant-Microbe Interactions ◽

10.1094/mpmi.2000.13.8.860 ◽

2000 ◽

Vol 13 (8) ◽

pp. 860-868 ◽

Cited By ~ 44

Author(s):

Ichiro Mitsuhara ◽

Hiroki Matsufuru ◽

Masahiro Ohshima ◽

Hisatoshi Kaku ◽

Yuki Nakajima ◽

...

Keyword(s):

Fungal Infection ◽

Transgenic Tobacco ◽

Pseudomonas Syringae ◽

Host Resistance ◽

Fungal Pathogens ◽

Erwinia Carotovora ◽

Induced Expression ◽

Sarcotoxin Ia ◽

Resistance To Infection

We demonstrate here that induced expression of sarcotoxin IA, a bactericidal peptide from Sarcophaga peregrina, enhanced the resistance of transgenic tobacco plants to both bacterial and fungal pathogens. The peptide was produced with a modified PR1a promoter, which is further activated by salicylic acid treatment and necrotic lesion formation by pathogen infection. Host resistance to infection of bacteria Erwinia carotovora subsp. carotovora and Pseudomonas syringae pv. tabaci was shown to be dependent on the amounts of sarcotoxin IA expressed. Since we found antifungal activity of the peptide in vitro, transgenic seedlings were also inoculated with fungal pathogens Rhizoctonia solani and Pythium aphanidermatum. Transgenic plants expressing higher levels of sarcotoxin were able to withstand fungal infection and remained healthy even after 4 weeks, while control plants were dead by fungal infection after 2 weeks.

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Light-induced expression of ipt from Agrobacterium tumefaciens results in cytokinin accumulation and osmotic stress symptoms in transgenic tobacco

Plant Molecular Biology ◽

10.1007/bf00042081 ◽

1995 ◽

Vol 28 (5) ◽

pp. 965-965 ◽

Cited By ~ 2

Keyword(s):

Agrobacterium Tumefaciens ◽

Osmotic Stress ◽

Transgenic Tobacco ◽

Induced Expression ◽

Stress Symptoms

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Functional Characterization of a Novel Promoter Element Required for an Innate Immune Response in Drosophila

Molecular and Cellular Biology ◽

10.1128/mcb.23.22.8272-8281.2003 ◽

2003 ◽

Vol 23 (22) ◽

pp. 8272-8281 ◽

Cited By ~ 21

Author(s):

Hanna Uvell ◽

Ylva Engström

Keyword(s):

Gene Expression ◽

Antimicrobial Peptide ◽

Functional Characterization ◽

Binding Activity ◽

Innate Immune ◽

Site Directed Mutagenesis ◽

Promoter Element ◽

Peptide Gene ◽

Inducible Genes

ABSTRACT Innate immune reactions are crucial processes of metazoans to protect the organism against overgrowth of faster replicating microorganisms. Drosophila melanogaster is a precious model for genetic and molecular studies of the innate immune system. In response to infection, the concerted action of a battery of antimicrobial peptides ensures efficient killing of the microbes. The induced gene expression relies on translocation of the Drosophila Rel transcription factors Relish, Dif, and Dorsal to the nucleus where they bind to κB-like motifs in the promoters of the inducible genes. We have identified another putative promoter element, called region 1 (R1), in a number of antimicrobial peptide genes. Site-directed mutagenesis of the R1 site diminished Cecropin A1 (CecA1) expression in transgenic Drosophila larvae and flies. Infection of flies induced a nuclear R1-binding activity that was unrelated to the κB-binding activity in the same extracts. Although the R1 motif was required for Rel protein-mediated CecA1 expression in cotransfection experiments, our data argue against it being a direct target for the Drosophila Rel proteins. We propose that the R1 and κB motifs are targets for distinct regulatory complexes that act in concert to promote high levels of antimicrobial peptide gene expression in response to infection.

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