scholarly journals Antifungal symbiotic peptide NCR044 exhibits unique structure and multifaceted mechanisms of action that confer plant protection

2020 ◽  
Vol 117 (27) ◽  
pp. 16043-16054
Author(s):  
Siva L. S. Velivelli ◽  
Kirk J. Czymmek ◽  
Hui Li ◽  
Jared B. Shaw ◽  
Garry W. Buchko ◽  
...  

In the indeterminate nodules of a model legumeMedicago truncatula, ∼700 nodule-specific cysteine-rich (NCR) peptides with conserved cysteine signature are expressed. NCR peptides are highly diverse in sequence, and some of these cationic peptides exhibit antimicrobial activity in vitro and in vivo. However, there is a lack of knowledge regarding their structural architecture, antifungal activity, and modes of action against plant fungal pathogens. Here, the three-dimensional NMR structure of the 36-amino acid NCR044 peptide was solved. This unique structure was largely disordered and highly dynamic with one four-residue α-helix and one three-residue antiparallel β-sheet stabilized by two disulfide bonds. NCR044 peptide also exhibited potent fungicidal activity against multiple plant fungal pathogens, includingBotrytis cinereaand threeFusariumspp. It inhibited germination in quiescent spores ofB. cinerea. In germlings, it breached the fungal plasma membrane and induced reactive oxygen species. It bound to multiple bioactive phosphoinositides in vitro. Time-lapse confocal and superresolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, subsequent accumulation in the cytoplasm, and elevated levels in nucleoli of germlings. Spray-applied NCR044 significantly reduced gray mold disease symptoms caused by the fungal pathogenB. cinereain tomato and tobacco plants, and postharvest products. Our work illustrates the antifungal activity of a structurally unique NCR peptide against plant fungal pathogens and paves the way for future development of this class of peptides as a spray-on fungistat/fungicide.

Author(s):  
Siva L. S. Velivelli ◽  
Kirk J. Czymmek ◽  
Hui Li ◽  
Jared B. Shaw ◽  
Garry W. Buchko ◽  
...  

AbstractNCR044.1 is a 36-amino acid nodule-specific cysteine-rich antimicrobial peptide expressed in the developing nodules of Medicago truncatula. Here, we determined its unique NMR structure to be largely disordered, one four-residue α-helix and one three-residue anti-parallel β-sheet stabilized by two disulfide bonds, suggesting it is highly dynamic. NCR044.1 exhibited potent fungicidal activity against multiple plant fungal pathogens. It breached the fungal plasma membrane, bound to multiple phosphoinositides, and induced reactive oxygen species. Time-lapse confocal and super-resolution microscopy revealed strong fungal cell wall binding, penetration of the cell membrane at discrete foci, followed by gradual loss of turgor, and subsequent accumulation in the cytoplasm with elevated levels in nucleoli. Nucleolar localization of NCR044.1 was unique amongst plant antifungal peptides, suggesting its potential interaction with ribosomes and inhibition of translation. Spray-applied NCR044.1 significantly reduced gray mold disease symptoms caused by the fungal pathogen Botrytis cinerea in tomato plants and post-harvest products demonstrating its potential as a spray-on peptide-based biofungicide.


Foods ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1430 ◽  
Author(s):  
Lina Šernaitė ◽  
Neringa Rasiukevičiūtė ◽  
Alma Valiuškaitė

Sustainable plant protection can be applied on apples against fungal pathogens such as Botrytis cinerea (which is responsible for gray mold)—a significant global postharvest disease. This pathogen can affect a wide range of hosts; and fruits may have variable susceptibilities to B. cinerea from different plant hosts. New possibilities to control gray mold in food production are under demand due to the emergence of resistance against antifungal agents in fungal pathogens. Cinnamon, pimento, and laurel extracts were previously assessed for antifungal activities under in vitro conditions and were found to have the potential to be effective against postharvest gray mold. Therefore, this study aimed to investigate the antifungal activity of cinnamon, pimento, and laurel extracts in vitro and against postharvest gray mold on apples to determine the susceptibility of apple fruits to B. cinerea from different plant hosts, and to analyze the chemical composition of the extracts. Apples (cv. “Connell Red”) were treated with different concentrations of extracts and inoculated with B. cinerea isolates from apple and strawberry followed by evaluation of in vitro antifungal activity. The results reveal that most of the concentrations of the extracts that were investigated were not efficient enough when assessed in the postharvest assay, despite having demonstrated a high in vitro antifungal effect. Apples were less susceptible to B. cinerea isolated from strawberry. To conclude, cinnamon extract was found to be the most effective against apple gray mold; however, higher concentrations of the extracts are required for the efficient inhibition of B. cinerea in fruits during storage.


2021 ◽  
Author(s):  
Pamela R. Avila ◽  
Graciela Juez Castillo ◽  
Carel E. Carvajal

Abstract Fungal diseases are a current problem in agriculture causing significant losses in several crops whereby its prevention and treatment is of utmost importance. The Chitosan nanoparticles (ChNPs) were evaluated for their antimicrobial activity against the phytopathogen Fusarium solani. The chitosan concentration in nanoparticles that showed antifungal activity was 2.0 µg/mL. ChNPs showed to be a potential antifungal candidate with applications in phytosanitary control. Transmission electron microscopy (TEM) results showed damage to the fungal cell wall and membrane caused by the nanoparticles interaction with these structures affecting fungal growth and development in in vitro as in in vivo assay where microscopy demonstrated the internalization of nanoparticles aggregates within plant root cells cytoplasm up to 45 days. Therefore ChNPs nanoparticles could be an alternative method for diseases caused by Fusarium solani instead of chemical fungicides commonly used for treating tomato root rot.


Molecules ◽  
2020 ◽  
Vol 25 (4) ◽  
pp. 903
Author(s):  
Miklós Nagy ◽  
Gábor Szemán-Nagy ◽  
Alexandra Kiss ◽  
Zsolt László Nagy ◽  
László Tálas ◽  
...  

Multiple drug resistant fungi pose a serious threat to human health, therefore the development of completely new antimycotics is of paramount importance. The in vitro antifungal activity of the original, 1-amino-5-isocyanonaphthalenes (ICANs) was evaluated against reference strains of clinically important Candida species. Structure-activity studies revealed that the naphthalene core and the isocyano- together with the amino moieties are all necessary to exert antifungal activity. 1,1-N-dimethylamino-5-isocyanonaphthalene (DIMICAN), the most promising candidate, was tested further in vitro against clinical isolates of Candida species, yielding a minimum inhibitory concentration (MIC) of 0.04–1.25 µg/mL. DIMICAN was found to be effective against intrinsically fluconazole resistant Candida krusei isolates, too. In vivo experiments were performed in a severly neutropenic murine model inoculated with a clinical strain of Candida albicans. Daily administration of 5 mg/kg DIMICAN intraperitoneally resulted in 80% survival even at day 13, whereas 100% of the control group died within six days. Based on these results, ICANs may become an effective clinical lead compound family against fungal pathogens.


Author(s):  
Mrridula Dangi Narwal ◽  
Meenakshi Balhara ◽  
Renu Chaudhary ◽  
Chhillar Ak

Scientific and clinical reports globally demonstrated that the opportunistic mycotic infections are at major risk to the human fitness. In past few decades, development of resistance in microbes to existing antifungals, has emphasized on the search of new antimycotic drugs. As a matter of fact "echinocandins" are new categories of broad-spectrum antifungal enlighten a hope in this direction. Echinocandins are bulky lipopeptides that inhibits the production of β-[1,3]-glucan "a major constituent of fungal cell wall" which ultimately leads to the death of fungal pathogens. In vitro as well as in vivo published reports have demonstrated that the echinocandins exhibit fungicidal activity against most Candida spp while fungistatic against Aspergillus spp and exclusively found to be more effective when tested in combination with polyenes/azoles. Present article is an expert views on the recent and historical literature available on the antifungal therapies with accessing their impact on the human health. Emphasis is given on the utility of the echinocandins as potential antifungal agent by discussing recent examples of clinical and laboratory studies including the use of improved proteomics approaches to know a bit more about the interaction of human host and fungal pathogens.


Author(s):  
NUZHAT TABASSUM ◽  
VIDYASAGAR G. M. ◽  
RAGHUNANDAN D ◽  
SHIVAKUMAR I

Objectives: The aim of the present study is to isolate an antifungal compound from Derris indica (Lam) Bennett seed oil with various solvents and evaluation of its antifungal activity against the clinical species of Candida. Methods: D. indica seed hexane extract was tested against Trichophyton rubrum, Trichophyton tonsurans and Candida albicans. Hexane extract was fractioned using different solvents through column chromatography (CC). Isolated compound D1 was identified and characterized using ultraviolet, Fourier-transform infrared, 1HNMR, and mass spectroscopy. In vitro evaluation of D1 carried out against 12 Candida strains. In vivo evaluation of D1 carried out against T. rubrum, T. tonsurans, and C. albicans using an excision wound healing model on male Wistar rats. Results: Different concentrations of hexane extract showed antimicrobial activity against tested microorganism with varying minimum inhibitory concentration values. On fractionation with hexane-petroleum ether through CC, it yielded a crystalline fraction. Compound D1 characterized as a 3,5-bis (4,4’’-dimethoxy-[1,1’: 2’,1’’-terphenyl]-4’-yl)-4H-pyrazole-4,4-diol. A novel alkaloid compound from D. indica is a new report and proved to be inhibitory against C. albicans MTCC 3017 (14.83±0.28), MTCC 1637 (16.0±0.0), Candida glabrata MTCC 3814 (16.83±0.28) and MTCC 3014 (16.66±0.57), Candida tropicalis MTCC 230 (20.0±0.0), MTCC 1406 (12.33±0.57). C. glabrata MTCC 3981 was found to be resistant to the compound. In vivo studies showed no visual symptoms at the end of treatment indicating the therapeutic property of the compound. Conclusion: The D1 was found to be effective against human fungal pathogens and can be used as a base molecule in designing new antifungal drugs.


Author(s):  
Elif Canpolat ◽  
Müzeyyen Müge Doğaner ◽  
Sibel Derviş ◽  
Çiğdem Ulubaş Serçe

Developing as an alternative plant disease control method by using beneficial microorganisms and their metabolites has gained so much importance in recent years. In this study, the possibilities of using microorganisms which have potential antimicrobial effects on controlling soil-borne fungi at strawberry production were investigated. Effects of different lactic acid bacteria (LAB) strains on the development of several soil-borne fungi were studied in vitro and in vivo. LAB were screened for antifungal activity by using cell free supernatant against Fusarium sp., Rhizoctonia sp., Macrophomina sp., Botrytis sp., Phtopythium sp., Cylindrocarpon sp. and Pestalotiopsis sp. Cell free supernatant of LAB isolates showed promising antifungal activity. In vitro effective strains of LAB were tested in pot experiments to search their effects on disease development and plant growth. While the antifungal effects of all LAB strains tested in vitro experiments exhibited promising results, in vivo experiments revealed similar effects on different fungi genera.


Author(s):  
Raul I. Garcia ◽  
Evelyn A. Flynn ◽  
George Szabo

Skin pigmentation in mammals involves the interaction of epidermal melanocytes and keratinocytes in the structural and functional unit known as the Epidermal Melanin Unit. Melanocytes(M) synthesize melanin within specialized membrane-bound organelles, the melanosome or pigment granule. These are subsequently transferred by way of M dendrites to keratinocytes(K) by a mechanism still to be clearly defined. Three different, though not necessarily mutually exclusive, mechanisms of melanosome transfer have been proposed: cytophagocytosis by K of M dendrite tips containing melanosomes, direct injection of melanosomes into the K cytoplasm through a cell-to-cell pore or communicating channel formed by localized fusion of M and K cell membranes, release of melanosomes into the extracellular space(ECS) by exocytosis followed by K uptake using conventional phagocytosis. Variability in methods of transfer has been noted both in vivo and in vitro and there is evidence in support of each transfer mechanism. We Have previously studied M-K interactions in vitro using time-lapse cinemicrography and in vivo at the ultrastructural level using lanthanum tracer and freeze-fracture.


2020 ◽  
Vol 8 (10) ◽  
pp. 1627
Author(s):  
Tecla Ciociola ◽  
Pier Paolo Zanello ◽  
Tiziana D’Adda ◽  
Serena Galati ◽  
Stefania Conti ◽  
...  

The growing problem of antimicrobial resistance highlights the need for alternative strategies to combat infections. From this perspective, there is a considerable interest in natural molecules obtained from different sources, which are shown to be active against microorganisms, either alone or in association with conventional drugs. In this paper, peptides with the same sequence of fragments, found in human serum, derived from physiological proteins, were evaluated for their antifungal activity. A 13-residue peptide, representing the 597–609 fragment within the albumin C-terminus, was proved to exert a fungicidal activity in vitro against pathogenic yeasts and a therapeutic effect in vivo in the experimental model of candidal infection in Galleria mellonella. Studies by confocal microscopy and transmission and scanning electron microscopy demonstrated that the peptide penetrates and accumulates in Candida albicans cells, causing gross morphological alterations in cellular structure. These findings add albumin to the group of proteins, which already includes hemoglobin and antibodies, that could give rise to cryptic antimicrobial fragments, and could suggest their role in anti-infective homeostasis. The study of bioactive fragments from serum proteins could open interesting perspectives for the development of new antimicrobial molecules derived by natural sources.


2021 ◽  
Vol 7 (6) ◽  
pp. 428
Author(s):  
Men Thi Ngo ◽  
Minh Van Nguyen ◽  
Jae Woo Han ◽  
Myung Soo Park ◽  
Hun Kim ◽  
...  

In the search for antifungal agents from marine resources, we recently found that the culture filtrate of Trichoderma longibrachiatum SFC100166 effectively suppressed the development of tomato gray mold, rice blast, and tomato late blight. The culture filtrate was then successively extracted with ethyl acetate and n-butanol to identify the fungicidal metabolites. Consequently, a new compound, spirosorbicillinol D (1), and a new natural compound, 2′,3′-dihydro-epoxysorbicillinol (2), together with 11 known compounds (3–13), were obtained from the solvent extracts. The chemical structures were determined by spectroscopic analyses and comparison with literature values. The results of the in vitro antifungal assay showed that of the tested fungal pathogens, Phytophthora infestans was the fungus most sensitive to the isolated compounds, with MIC values ranging from 6.3 to 400 µg/mL, except for trichotetronine (9) and trichodimerol (10). When tomato plants were treated with the representative compounds (4, 6, 7, and 11), bisvertinolone (6) strongly reduced the development of tomato late blight disease compared to the untreated control. Taken together, our results revealed that the culture filtrate of T. longibrachiatum SFC100166 and its metabolites could be useful sources for the development of new natural agents to control late blight caused by P. infestans.


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