2023-08-28 10:15:02
Penicillium digitatum is the fungus that causes green rot in citrus, the so-called ‘green mold’, the main post-harvest disease that causes large economic losses worldwide.
To combat it, a research group from the Institute of Agrochemistry and Food Technology (IATA), of the Higher Council for Scientific Research (CSIC) in Spain, is studying the possibilities of a type of antifungal protein called AFPs, produced by filamentous fungi. And these scientists have discovered that one of these proteins has multiple effects against this threat, hindering the appearance of resistance and allowing the development of new antifungals. In addition to their application in post-harvest protection, these proteins can be applied in the field of medicine, agriculture and food technology.
The aforementioned team is the Research Group on Bioactive Proteins and Peptides of Interest in Agrifood, and is directed by José F. Marcos and Paloma Manzanares. The group works on the characterization of antifungal proteins such as AFPs. They are small and very stable, and have the ability to prevent the growth of pathogenic fungi, both those that affect humans and plants, as well as fungi that spoil food and produce toxic compounds. Recently, a team of scientists from this group, led by Carolina Ropero-Pérez from IATA, managed to describe how the AfpB antifungal protein works against the fungus Penicillium digitatum.
The most relevant results indicate that the AfpB protein has a multiple mode of action against this fungus: it prevents it from defending itself by producing toxic compounds (it represses the genes that encode these compounds); causes programmed cell death (cell apoptosis) in the fungus; Furthermore, it affects the synthesis of acetoin, an organic compound produced by alcoholic fermentation that also contributes to the antifungal activity of AfpB.
“Finally, we saw that AfpB induces the expression of a gene that encodes a very particular extracellular protein made up of tandem amino acid repeats, which enhances the inhibitory activity of AfpB”, explains José F. Marcos.
To carry out this work, transcriptomic techniques such as RNAseq technology were used, a highly sensitive and precise RNA sequencing methodology to study the expression of the set of genes of an organism under different conditions (different culture conditions, presence or absence of certain compounds, etc.).
“The use of RNAseq to study the mechanism of action of AfpB against Penicillium digitatum has allowed us to know which genes present a stronger response, both induction and repression, in the presence of said protein, and, therefore, which pathways metabolic processes associated with these genes are more affected by the antifungal action of AfpB”, describes Paloma Manzanares. Furthermore, these transcriptomic analyzes were then functionally validated.
Orange is one of the most consumed citrus fruits by humanity. Unfortunately, like other citrus fruits, it is vulnerable to the Penicillium digitatum fungus. (Photo: Amanda Mills/CDC)
Applications
Fungal infections threaten human health and have a negative impact on food safety, damaging agricultural production and causing animal diseases. “Currently, there are only a few classes of fungicides available on the market,” says Sandra Garrigues, a postdoctoral researcher at IATA who participated in this study. “This, together with the fact that the excessive use of fungicides in agriculture has caused the development of resistant fungi, makes it very necessary to obtain alternative antifungal molecules to those that already exist and with a different mode of action, to combat pathogenic fungi,” says the CSIC researcher.
“AFPs, such as AfpB, offer great potential as new biofungicides to control these harmful fungi, and their application would be possible in the fields of medicine, agriculture, post-harvest protection, and food technology,” he points out. apple orchards “This work delves into the study of the mode of action of AfpB in particular, which has multiple targets, which hinders the appearance of resistance and makes it possible to develop new antifungals based on this protein or similar ones”, he remarks.
The study is titled “Transcriptomic Profile of Penicillium digitatum Reveals Novel Aspects of the Mode of Action of the Antifungal Protein AfpB”. And it has been published in the academic journal Microbiology Spectrum. (Source: Isidoro Garcia / CSIC)
#Proteins #fungi #damage #citrus