1
|
Fodil S, De Zotti M, Tundo S, Gabbatore L, Vettorazzo I, Luti S, Musetti R, Sella L, Favaron F, Baccelli I. Multiple lysine substitutions in the peptaibol trichogin GA IV enhance the antibiotic activity against plant pathogenic Pseudomonas syringae. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2024; 201:105901. [PMID: 38685232 DOI: 10.1016/j.pestbp.2024.105901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/05/2024] [Accepted: 04/06/2024] [Indexed: 05/02/2024]
Abstract
Plant diseases caused by Pseudomonas syringae are essentially controlled in the field with the use of copper-based products and antibiotics, raising environmental and safety concerns. Antimicrobial peptides (AMPs) derived from fungi may represent a sustainable alternative to those chemicals. Trichogin GA IV, a non-ribosomal, 11-residue long AMP naturally produced by the fungus Trichoderma longibrachiatum has the ability to insert into phospholipidic membranes and form water-filled pores, thereby perturbing membrane integrity and permeability. In previous studies, peptide analogs modified at the level of specific residues were designed to be water-soluble and active against plant pathogens. Here, we studied the role of glycine-to-lysine substitutions and of the presence of a C-terminal leucine amide on bioactivity against Pseudomonas syringae bacteria. P. syringae diseases affect a wide range of crops worldwide, including tomato and kiwifruit. Our results show that trichogin GA IV analogs containing two or three Gly-to-Lys substitutions are highly effective in vitro against P. syringae pv. tomato (Pst), displaying minimal inhibitory and minimal bactericidal concentrations in the low micromolar range. The same analogs are also able to inhibit in vitro the kiwifruit pathogen P. syringae pv. actinidiae (Psa) biovar 3. When sprayed on tomato plants 24 h before Pst inoculation, only tri-lysine containing analogs were able to significantly reduce bacterial titers and symptom development in infected plants. Our results point to a positive correlation between the number of lysine substitutions and the antibacterial activity. This correlation was supported by microscopy analyses performed with mono-, di- and tri-Lys containing analogs that showed a different degree of interaction with Pst cells and ultrastructural changes that culminated in cell lysis.
Collapse
Affiliation(s)
- Sihem Fodil
- Institute for Sustainable Plant Protection, National Research Council of Italy, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Marta De Zotti
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131 Padova, Italy.
| | - Silvio Tundo
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Viale Dell' Università 16, 35020 Legnaro, Italy; Department of Agronomy, Food, Natural Resources, Animals and Environment (DAFNAE), University of Padova, Viale Dell' Università 16, 35020 Legnaro, Italy
| | - Laura Gabbatore
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Irene Vettorazzo
- Department of Chemistry, University of Padova, Via Marzolo 1, 35131 Padova, Italy
| | - Simone Luti
- Department of Experimental and Clinical Biomedical Sciences, University of Florence, Viale Morgagni 50, 50134 Firenze, Italy
| | - Rita Musetti
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Viale Dell' Università 16, 35020 Legnaro, Italy
| | - Luca Sella
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Viale Dell' Università 16, 35020 Legnaro, Italy
| | - Francesco Favaron
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Viale Dell' Università 16, 35020 Legnaro, Italy
| | - Ivan Baccelli
- Institute for Sustainable Plant Protection, National Research Council of Italy, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy.
| |
Collapse
|
2
|
Pereira-Dias L, Oliveira-Pinto PR, Fernandes JO, Regalado L, Mendes R, Teixeira C, Mariz-Ponte N, Gomes P, Santos C. Peptaibiotics: Harnessing the potential of microbial secondary metabolites for mitigation of plant pathogens. Biotechnol Adv 2023; 68:108223. [PMID: 37536466 DOI: 10.1016/j.biotechadv.2023.108223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 07/28/2023] [Accepted: 07/31/2023] [Indexed: 08/05/2023]
Abstract
Agricultural systems are in need of low-cost, safe antibiotics to protect crops from pests and diseases. Peptaibiotics, a family of linear, membrane-active, amphipathic polypeptides, have been shown to exhibit antibacterial, antifungal, and antiviral activity, and to be inducers of plant resistance against a wide range of phytopathogens. Peptaibiotics belong to the new generation of alternatives to agrochemicals, aligned with the United Nations Sustainable Development Goals and the One Health approach toward ensuring global food security and safety. Despite that, these fungi-derived, non-ribosomal peptides remain surprisingly understudied, especially in agriculture, where only a small number has been tested against a reduced number of phytopathogens. This lack of adoption stems from peptaibiotics' poor water solubility and the difficulty to synthesize and purify them in vitro, which compromises their delivery and inclusion in formulations. In this review, we offer a comprehensive analysis of peptaibiotics' classification, biosynthesis, relevance to plant protection, and mode of action against phytopathogens, along with the techniques enabling researchers to extract, purify, and elucidate their structure, and the databases holding such valuable data. It is also discussed how chemical synthesis and ionic liquids could increase their solubility, how genetic engineering and epigenetics could boost in vitro production, and how omics can reduce screenings' workload through in silico selection of the best candidates. These strategies could turn peptaibiotics into effective, ultra-specific, biodegradable tools for phytopathogen control.
Collapse
Affiliation(s)
- Leandro Pereira-Dias
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; Instituto de Conservación y Mejora de la Agrodiversidad Valenciana, Universitat Politècnica de València, 46022, Valencia, Spain.
| | - Paulo R Oliveira-Pinto
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Juliana O Fernandes
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Laura Regalado
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Rafael Mendes
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Cátia Teixeira
- LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Nuno Mariz-Ponte
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| | - Paula Gomes
- LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; Department of Chemistry and Biochemistry, Faculty of Sciences, University of Porto, 4169-007 Porto, Portugal
| | - Conceição Santos
- iB(2) Laboratory, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal; LAQV-REQUIMTE, Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre s/n, 4169-007 Porto, Portugal
| |
Collapse
|
3
|
Bolzonello A, Morbiato L, Tundo S, Sella L, Baccelli I, Echeverrigaray S, Musetti R, De Zotti M, Favaron F. Peptide Analogs of a Trichoderma Peptaibol Effectively Control Downy Mildew in the Vineyard. PLANT DISEASE 2023; 107:2643-2652. [PMID: 36724095 DOI: 10.1094/pdis-09-22-2064-re] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Plasmopara viticola, the agent of grapevine downy mildew, causes enormous economic damage, and its control is primarily based on the use of synthetic fungicides. The European Union policies promote reducing reliance on synthetic plant protection products. Biocontrol agents such as Trichoderma spp. constitute a resource for the development of biopesticides. Trichoderma spp. produce secondary metabolites such as peptaibols, but the poor water solubility of peptaibols limits their practical use as agrochemicals. To identify new potential bio-inspired molecules effective against P. viticola, various water-soluble peptide analogs of the peptaibol trichogin were synthesized. In grapevine leaf disk assays, the peptides analogs at a concentration of 50 μM completely prevented P. viticola infection after zoosporangia inoculation. Microscopic observations of one of the most effective peptides showed that it causes membrane lysis and cytoplasmic granulation in both zoosporangia and zoospores. Among the effective peptides, 4r was selected for a 2-year field trial experiment. In the vineyard, the peptide administered at 100 μM (equivalent to 129.3 g/ha) significantly reduced the disease incidence and severity on both leaves and bunches, with protection levels similar to those obtained using a cupric fungicide. In the second-year field trial, reduced dosages of the peptide were also tested, and even at the peptide concentration reduced by 50 or 75%, a significant decrease in the disease incidence and severity was obtained at the end of the trial. The peptide did not show any phytotoxic effect. Previously, peptide 4r had been demonstrated to be active against other fungal pathogens, including the grapevine fungus Botrytis cinerea. Thus, this peptide may be a candidate for a broad-spectrum fungicide whose biological properties deserve further investigation.
Collapse
Affiliation(s)
- Angela Bolzonello
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro I-35020, Italy
| | - Laura Morbiato
- Department of Chemistry, University of Padova, Padova I-35131, Italy
| | - Silvio Tundo
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro I-35020, Italy
| | - Luca Sella
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro I-35020, Italy
| | - Ivan Baccelli
- Institute for Sustainable Plant Protection, National Research Council of Italy, Sesto Fiorentino I-50019, Italy
| | - Sergio Echeverrigaray
- Institute of Biotechnology, University of Caxias do Sul, Caxias do Sul, RS 95070-560, Brazil
| | - Rita Musetti
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro I-35020, Italy
| | - Marta De Zotti
- Department of Chemistry, University of Padova, Padova I-35131, Italy
| | - Francesco Favaron
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro I-35020, Italy
| |
Collapse
|
4
|
Dalla Torre C, Sannio F, Battistella M, Docquier JD, De Zotti M. Peptaibol Analogs Show Potent Antibacterial Activity against Multidrug Resistant Opportunistic Pathogens. Int J Mol Sci 2023; 24:ijms24097997. [PMID: 37175704 PMCID: PMC10178204 DOI: 10.3390/ijms24097997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 04/19/2023] [Accepted: 04/22/2023] [Indexed: 05/15/2023] Open
Abstract
New classes of antibacterial drugs are urgently needed to address the global issue of antibiotic resistance. In this context, peptaibols are promising membrane-active peptides since they are not involved in innate immunity and their antimicrobial activity does not involve specific cellular targets, therefore reducing the chance of bacterial resistance development. Trichogin GA IV is a nonhemolytic, natural, short-length peptaibol active against Gram-positive bacteria and resistant to proteolysis. In this work, we report on the antibacterial activity of cationic trichogin analogs. Several peptides appear non-hemolytic and strongly active against many clinically relevant bacterial species, including antibiotic-resistant clinical isolates, such as Staphylococcus aureus, Acinetobacter baumannii, and extensively drug-resistant Pseudomonas aeruginosa, against which there are only a limited number of antibiotics under development. Our results further highlight how the modification of natural peptides is a valuable strategy for obtaining improved antibacterial agents with potential therapeutic applications.
Collapse
Affiliation(s)
- Chiara Dalla Torre
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Filomena Sannio
- Dipartimento di Biotecnologie Mediche, University of Siena, Viale Bracci 16, I-53100 Siena, Italy
| | - Mattia Battistella
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| | - Jean-Denis Docquier
- Dipartimento di Biotecnologie Mediche, University of Siena, Viale Bracci 16, I-53100 Siena, Italy
- Lead Discovery Siena s.r.l., Via Fiorentina 1, I-53100 Siena, Italy
- Laboratoire de Bactériologie Moléculaire, Centre d'Ingénierie des Protéines-UR InBioS, University of Liège, Allée du Six Août 11, B-4000 Liège, Belgium
| | - Marta De Zotti
- Department of Chemical Sciences, University of Padova, Via Marzolo 1, I-35131 Padova, Italy
| |
Collapse
|
5
|
Anticancer and Targeting Activity of Phytopharmaceutical Structural Analogs of a Natural Peptide from Trichoderma longibrachiatum and Related Peptide-Decorated Gold Nanoparticles. Int J Mol Sci 2023; 24:ijms24065537. [PMID: 36982610 PMCID: PMC10057332 DOI: 10.3390/ijms24065537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/08/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
In the large field of bioactive peptides, peptaibols represent a unique class of compounds. They are membrane-active peptides, produced by fungi of the genus Trichoderma and known to elicit plant defenses. Among the short-length peptaibols, trichogin GA IV is nonhemolytic, proteolysis-resistant, antibacterial, and cytotoxic. Several trichogin analogs are endowed with potent activity against phytopathogens, thus representing a sustainable alternative to copper for plant protection. In this work, we tested the activity of trichogin analogs against a breast cancer cell line and a normal cell line of the same derivation. Lys-containing trichogins showed an IC50 below 12 µM, a peptide concentration not significantly affecting the viability of normal cells. Two analogs were found to be membrane-active but noncytotoxic. They were anchored to gold nanoparticles (GNPs) and further investigated for their ability to act as targeting agents. GNP uptake by cancer cells increased with peptide decoration, while it decreased in the corresponding normal epithelial cells. This work highlights the promising biological properties of peptaibol analogs in the field of cancer therapy either as cytotoxic molecules or as active targeting agents in drug delivery.
Collapse
|
6
|
Caracciolo R, Sella L, De Zotti M, Bolzonello A, Armellin M, Trainotti L, Favaron F, Tundo S. Efficacy of Trichoderma longibrachiatum Trichogin GA IV Peptaibol analogs against the Black Rot Pathogen Xanthomonas campestris pv. campestris and other Phytopathogenic Bacteria. Microorganisms 2023; 11:microorganisms11020480. [PMID: 36838445 PMCID: PMC9967956 DOI: 10.3390/microorganisms11020480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/17/2023] Open
Abstract
Black rot caused by the Gram-negative bacterial pathogen Xanthomonas campestris pv. campestris (Xcc) is considered one of the most destructive diseases affecting crucifers. Xcc is a seedborne pathogen able to infect the host at any growth stage. The management of the pathogen mainly relies on the use of copper-based products with possible negative effects on human health and the environment. Searching for protection alternatives is crucial for achieving a sustainable management of Xcc. Trichoderma spp. has been largely used as a biocontrol agent against several phytopathogens. Among Trichoderma species, Trichoderma longibrachiatum produces the peptaibol trichogin GA IV, a secondary metabolite with antimicrobial activity against Gram-positive bacteria, as well as filamentous and yeast-like fungi. In this work, we tested, at micromolar concentrations, 25 synthetic analogs of the peptaibol trichogin GA IV for their bacteriostatic and bactericidal activity toward the bacterium Xcc. One of the most effective peptides (4r) was also tested against the Gram-negative bacteria Xanthomonas arboricola, Pseudomonas corrugata, Pseudomonas savastanoi pv. savastanoi, Agrobacterium tumefaciens, Ralstonia solanacearum, and Erwinia carotovora subsp. carotovora, as well as the Gram-positive bacterium Bacillus subtilis. The peptide 4r reduced black rot symptoms on cauliflower plants when administered both before and 24 h after inoculation with Xcc. The cytotoxic activity of the peptide 4r was also evaluated towards suspensions of tobacco cells by Evans Blue assay.
Collapse
Affiliation(s)
- Rocco Caracciolo
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, 35020 Legnaro, Italy
| | - Luca Sella
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, 35020 Legnaro, Italy
| | - Marta De Zotti
- Department of Chemistry, University of Padova, 35131 Padova, Italy
| | - Angela Bolzonello
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, 35020 Legnaro, Italy
| | - Marco Armellin
- Department of Biology (DiBio), University of Padova, 35121 Padova, Italy
| | - Livio Trainotti
- Department of Biology (DiBio), University of Padova, 35121 Padova, Italy
| | - Francesco Favaron
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, 35020 Legnaro, Italy
| | - Silvio Tundo
- Department of Land, Environment, Agriculture and Forestry (TESAF), University of Padova, 35020 Legnaro, Italy
- Correspondence:
| |
Collapse
|
7
|
Guzmán-Guzmán P, Kumar A, de los Santos-Villalobos S, Parra-Cota FI, Orozco-Mosqueda MDC, Fadiji AE, Hyder S, Babalola OO, Santoyo G. Trichoderma Species: Our Best Fungal Allies in the Biocontrol of Plant Diseases-A Review. PLANTS (BASEL, SWITZERLAND) 2023; 12:plants12030432. [PMID: 36771517 PMCID: PMC9921048 DOI: 10.3390/plants12030432] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/08/2023] [Accepted: 01/13/2023] [Indexed: 06/02/2023]
Abstract
Biocontrol agents (BCA) have been an important tool in agriculture to prevent crop losses due to plant pathogens infections and to increase plant food production globally, diminishing the necessity for chemical pesticides and fertilizers and offering a more sustainable and environmentally friendly option. Fungi from the genus Trichoderma are among the most used and studied microorganisms as BCA due to the variety of biocontrol traits, such as parasitism, antibiosis, secondary metabolites (SM) production, and plant defense system induction. Several Trichoderma species are well-known mycoparasites. However, some of those species can antagonize other organisms such as nematodes and plant pests, making this fungus a very versatile BCA. Trichoderma has been used in agriculture as part of innovative bioformulations, either just Trichoderma species or in combination with other plant-beneficial microbes, such as plant growth-promoting bacteria (PGPB). Here, we review the most recent literature regarding the biocontrol studies about six of the most used Trichoderma species, T. atroviride, T. harzianum, T. asperellum, T. virens, T. longibrachiatum, and T. viride, highlighting their biocontrol traits and the use of these fungal genera in Trichoderma-based formulations to control or prevent plant diseases, and their importance as a substitute for chemical pesticides and fertilizers.
Collapse
Affiliation(s)
- Paulina Guzmán-Guzmán
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico
| | - Ajay Kumar
- Department of Postharvest Science, ARO, Volcani Center, Bet Dagan 50250, Israel
| | | | - Fannie I. Parra-Cota
- Campo Experimental Norman E. Borlaug, Instituto Nacional de Investigaciones Forestales, Agrícolas y Pecuarias (INIFAP), Ciudad Obregón 85000, Mexico
| | | | - Ayomide Emmanuel Fadiji
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Sajjad Hyder
- Department of Botany, Government College Women University Sialkot, Sialkot 51310, Pakistan
| | - Olubukola Oluranti Babalola
- Food Security and Safety Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Private Bag X2046, Mmabatho 2735, South Africa
| | - Gustavo Santoyo
- Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, Morelia 58030, Mexico
| |
Collapse
|
8
|
Baccelli I, Luti S, Bernardi R, Favaron F, De Zotti M, Sella L. Water-Soluble Trichogin GA IV-Derived Peptaibols Protect Tomato Plants From Botrytis cinerea Infection With Limited Impact on Plant Defenses. FRONTIERS IN PLANT SCIENCE 2022; 13:881961. [PMID: 35665189 PMCID: PMC9161086 DOI: 10.3389/fpls.2022.881961] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 04/27/2022] [Indexed: 06/02/2023]
Abstract
Peptaibols are non-ribosomal linear peptides naturally produced by a wide variety of fungi and represent the largest group of peptaibiotic molecules produced by Trichoderma species. Trichogin GA IV is an 11-residue lipopeptaibol naturally produced by Trichoderma longibrachiatum. Peptaibols possess the ability to form pores in lipid membranes or perturb their surface, and have been studied as antibiotics or anticancer drugs in human medicine, or as antimicrobial molecules against plant pathogens. When applied to plants, peptaibols may also elicit defense responses. A major drawback to the exploitation and application of peptaibols in agriculture is their poor water solubility. In a previous study, we designed water-soluble Lys-containing Trichogin GA IV analogs, which were able to inhibit the growth of several fungal plant pathogens in vitro. In the present study, we shed light on the mechanism underpinning their efficacy on plants, focusing on six Trichogin GA IV analogs. Our results highlighted peptide hydrophilicity, rather than helix stability, as the major determinant of their activity against B. cinerea infection in tomato leaves. The peptides showed preventive but not curative efficacy against infection, and lack of translaminar activity, with results reproducible on two tomato cultivars, Marmande and Micro-Tom. Reactive oxygen species (ROS) detection analysis in tomato and Arabidopsis, and expression of defense genes in tomato, highlighted a transient and limited impact of the peptides on the plant defense system. The treatment did not result in significant modulation of defense genes or defense priming. The antimicrobial effect thus emerges as the only mechanism behind the plant protection ability exerted by water-soluble Trichogin GA IV analogs, and limited effects on the plant metabolism are expected to occur.
Collapse
Affiliation(s)
- Ivan Baccelli
- Institute for Sustainable Plant Protection, National Research Council of Italy, Sesto Fiorentino, Italy
| | - Simone Luti
- Institute for Sustainable Plant Protection, National Research Council of Italy, Sesto Fiorentino, Italy
| | - Rodolfo Bernardi
- Department of Agriculture, Food and Environment, University of Pisa, Pisa, Italy
| | - Francesco Favaron
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro, Italy
| | - Marta De Zotti
- Department of Chemistry, University of Padova, Padova, Italy
| | - Luca Sella
- Department of Land, Environment, Agriculture, and Forestry (TESAF), University of Padova, Legnaro, Italy
| |
Collapse
|