Transcriptome Sequencing Revealed an Inhibitory Mechanism of Recombinant Puroindoline B Protein on Aspergillus flavus

TL;DR

This study shows how a plant protein inhibits a harmful fungus by targeting specific genes, reducing its growth and toxin production.

Contribution

Identified MFS transporter genes mfs1 and mfs2 as key to the inhibitory effect of rPINB on Aspergillus flavus.

Findings

Gene deletion strains showed reduced sensitivity to rPINB, with lower growth and altered morphology.

MFS transporter genes mfs1 and mfs2 are crucial for rPINB's inhibitory effect on A. flavus.

rPINB significantly reduced aflatoxin B1 production in gene-deleted strains.

Abstract

Aspergillus flavus, a common food contaminant, poses health and economic risks. Previous research showed that recombinant Puroindoline B protein (rPINB) inhibited A. flavus by disrupting its cell wall, membrane, nuclear function, mitochondrial activity, and oxidative stress. This study used transcriptome technology to explore the impact of rPINB on A. flavus gene expression and created gene deletion strains to test the sensitivity to rPINB. RNA-Seq identified the differentially expressed genes (DEGs) affecting cell wall synthesis, membrane transport, oxidative stress, spore formation, and aflatoxin production. The MFS transporter genes AFLA_106900 (mfs1) and AFLA_106910 (mfs2) were crucial for an inhibitory effect of rPINB. The mutants exhibited reduced sensitivity to rPINB-mediated inhibition, indicating lower growth, sunken conidia, and shriveled hyphae, compared to the wild-type strain. The results also demonstrated decreased sensitivity to the stress agents affecting cell membranes, osmotic balance, and oxidation, alongside a significant reduction in AFB1 production in gene-deleted strains. These results suggested that mfs1 and mfs2 were essential for rPINB protein’s inhibition of A. flavus growth, laying the groundwork for the mold control strategies using plant proteins.

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