Morintides: cargo-free chitin-binding peptides from Moringa oleifera

Area of Science:

• Plant biochemistry
• Peptide science
• Mycology

Background:

• Hevein-like peptides are cysteine-rich, chitin-binding peptides crucial for plant defense against fungi.
• They are classified into 6C, 8C, and 10C subfamilies based on cysteine content.
• Typically, they possess a three-domain precursor structure, including a signal peptide, mature peptide, and a C-terminal domain with protein cargo (in 8C and 10C types).

Purpose of the Study:

• To isolate and characterize novel 8C-hevein-like peptides from Moringa oleifera.
• To investigate the biochemical properties, including chitin-binding and anti-fungal activity, of these new peptides.
• To elucidate the structural features and evolutionary significance of these peptides within the hevein-like family.

Main Methods:

• Isolation and characterization of peptides using proteomic analysis.
• Assessment of thermal and enzymatic stability.
• Chitin-binding assays.
• Fungal growth inhibition assays.
• Transcriptomic analysis to determine precursor structure.

Main Results:

• Two novel 8C-hevein-like peptides, morintides (mO1 and mO2), were identified from Moringa oleifera.
• Morintides are 44-amino acid peptides rich in cysteine, glycine, and hydrophilic residues.
• They demonstrated resistance to degradation, chitin-binding capability, and inhibition of phytopathogenic fungi.
• Morintides possess a unique three-domain precursor with a protein-cargo-free C-terminal domain, distinguishing them from other angiosperm 8C-hevein-like peptides.

Conclusions:

• The discovery of morintides expands the known diversity of hevein-like peptides.
• These findings highlight the anti-fungal potential and stability of 8C-hevein-like peptides.
• Morintides represent a distinct class of angiosperm hevein-like peptides due to their unique C-terminal domain structure.