Exploring the potential of Antifungal Peptides to suppress the Pathogenicity of the Botrytis cinerea and Grey Mould Disease in Grapes and Strawberries

Food safety has been intensively challenged by plant fungal pathogens all around the world and Botrytis cinerea which causes “Gray Mould Rot” (‘Botrytis Bunch Rot’) in fresh horticultural crops, is one of the crucial plant fungal pathogens in global agricultural industry. Currently, their effect has worsened due to globalization of markets and global climate change that facilitate the appearance of new fungal strains and their rapid spread. Botrytis cinerea causes huge financial impact globally as nearly 1400 crop plants and their yield are affected by this pathogen. One of the most significant infections impacting export wine and table grapes, B. cinerea infection, especially in Vitis vinifera (L), causes "gray mould rot" during postharvest period, harming entire berry clusters during packaging, transportation, and commercialization. Botrytis cinerea is the major pathogen in wine industry and the total economic loss of grape crop from this plant pathogen has been recorded as US$2 billion internationally. As fungal pathogens create devastating losses in plant crop and their harvest, as well as threat to human consumption through fungal toxins, control of the pathogen is a necessity. Agriculture and food industry mainly depend on synthetic chemical fungicides to control fungal pathogens. Due to negative effect on food safety and enhancing the resistance of pathogen by those chemical fungicides, reliance on traditional pesticides has decreased. As a result of new developments in crop protection, there is now more interest in sustainable and efficient alternatives to traditional pesticides. This research study creates an insight of short antimicrobial peptide as a sustainable green fungicide to control Botrytis cinerea devastating plant pathogen. Antimicrobial peptide activity, which is a natural defence mechanism of some living cells, has been tested against Botrytis cinerea. Bioassays were conducted for four types of Battacin analogues and two analogues of PAF32 peptide on different life stages of the pathogen. Out of six, two analogues of Battacin peptide, BX (Battacin inverso) and BD (Battacin two copy analogue) were very effective against Botrytis cinerea. BX analogue completely suppressed the growth of mycelium at 6.25 μM while spore germination was completely inhibited at the 12.5 μM concentrations of peptide BD and BX. Further it was established that the same Battacin analogue with different lengths (different number of copies) exhibited different levels of antifungal activity against different life stages of Botrytis fungal pathogen which can be attributed to the wide structural variations of cell walls, size and shape between mycelium structure and conidial spore cells of Botrytis. At the same time, differences in peptide chain length and number of positive charges of the peptides may also have an effect on their antifungal activity. Morphological studies revealed that, BX (Batacin inverso peptide) effectively caused cell lysis of the pathogen through disrupting the fungal membranes and inducing cellular toxicity in Botrytis fungal mycelium and spores. Additionally, BX increased ROS production (reactive oxygen species) in the pathogen cells and depolarize the mitochondrial membrane potential, which contribute to cell death. BX contributed towards down regulation of virulence gene BcHBF1, BcHex and BcCBH that correlate with suppression of the mycelial growth, spore germination and pathogenicity. Overall, these findings suggest that the BX peptide analogue causes membrane damage, organelle malfunction, interference with MMP, and oxidative stress, down regulation of key virulence genes, all of which led to the death of conidial spores and the hyphal mycelium of Botrytis cinerea. BX has the potential to be further developed as spray-on antifungal agents or slow-release packaging materials, to control Botrytis cinerea pathogen effectively and to protect grapes and strawberries from “Gray Mould Rot” disease in the field, storage and during transport, thus minimizing the loss of crop and commodities.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Chemistry

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2025

Author dc:creator

• Shiraz, Fathumma Rizana

Advisor dc:contributor.advisor

• Sarojini, Vijayalakshmi

• Antifungal peptides
• Botrytis cinerea
• grey mould disease

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/74522

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/74522