The cytotoxic properties of a plant lipid transfer protein involve membrane permeabilization of target cells

MARIANA CLELIA REGENTE; GIUDICI, A. M.; VILLALAIN, J.; DE-LA-CANAL, L.

Letters in Applied Microbiology

Wiley-Blackwell

Año: 2005 vol. 40 p. 183 - 189

0266-8254

Aims: To determine whether Ha-AP10, a member of the plant lipid-transfer proteins (LTPs) family produces a direct cytotoxic effect on fungal cells mediated by membrane permeabilization. LTPs can inhibit fungal growth and are considered members of the ubiquitous class of antimicrobial peptides. However, the way they exert their effects on target cells is not yet understood. Methods and Results: Viability assays demonstrate  that Ha-AP10 acts as a fungicidal compound but no harmful effect is observed on plant cells. Liposome leakage assays show that the protein induces a moderate release of fluorescent probes encapsulated in model membranes, indicating its ability to interact with phospholipids. Using a fluorescent indicator of damage at the membrane level, we demonstrate that Ha-AP10 is able to induce the permeabilization of intact fungal spores in a dose-dependent manner. Conclusion: The results presented here demonstrate the permeabilization of fungal spores caused by Ha-AP10. Significance and Impact of the Study: To our knowledge, this is the first demonstration of fungal membrane damage by a LTP, giving a clue to elucidate the basis of its antimicrobial properties.