Biotive protease inhibitor from leaves of Capsicum annuum L.: Potential use as an antifungal molecule against Colletotrichum scovillei

Background

A diverse set of antimicrobial molecules have been found mainly in the seeds and fruits of Capsicum annuum UENF1381, accession resistant to different phytopathogenic microorganisms, like bacteria of the genus Xanthomonas and fungi of the genus Colletotrichum. However, there is little information about the defense mechanisms in other plant organs. The work aimed to study the induction of resistance in leaves and roots of C. annuum through the identification and characterization of antimicrobial peptides against Colletotrichum scovillei, one of the main pathogens of the crop.

Results

Based on the results of differential protein expression in response to infection, the extracts, LC₄₈ (Control Leaf mock inoculated 48 h), and RC₄₈ (Control Root mock inoculated 48 h) were selected. Analysis on the HPLC system resulted in 23 fractions (L1 to L23) obtained from the LC₄₈ extract and 27 fractions from the RC₄₈ extract (R1 to R27). Our results show that 10 μg mL⁻¹ of the L1 fraction is able to inhibit 88.4% of fungal growth, causing cell membrane permeabilization, endogenous reactive oxygen species induction and mitochondrial activity reduction. The peptide in the L1 fraction, named CaLPI, showed similarities with different sequences of proteinase inhibitors.

Conclusion

The study provides information on the diversity of antimicrobial proteins and peptides present in the leaves and roots of C. annuum UENF1381. With these results, we hope to contribute to the use of peptides as potential molecules in microbial control.