Nosema sp. PM-1, a new isolate of microsporidian from infected Papilio machaon Linnaeus, based on ultrastructure and molecular identification

Area of Science:

• Microbiology
• Entomology
• Parasitology

Background:

• Microsporidia are obligate intracellular parasites with a wide host range.
• The genus Nosema includes important insect pathogens.
• Understanding Nosema diversity and host interactions is crucial for ecological and agricultural contexts.

Purpose of the Study:

• To characterize a newly isolated microsporidium, Nosema sp. PM-1, from Papilio machaon.
• To determine the phylogenetic placement of Nosema sp. PM-1 within the Nosema genus.
• To assess the potential host range expansion of Nosema.

Main Methods:

• Isolation and morphological characterization of Nosema sp. PM-1.
• Ultrastructural analysis of microsporidian spores.
• Molecular characterization using rRNA, RNA polymerase II, and tubulin gene sequencing.
• Phylogenetic analysis to determine evolutionary relationships.

Main Results:

• Nosema sp. PM-1 exhibits typical Nosema spore morphology (3.22 μm × 1.96 μm, long oval) and ultrastructure.
• Complete rRNA gene sequence analysis confirmed its classification within the Nosema genus.
• Phylogenetic analyses placed Nosema sp. PM-1 as a sister taxon to a clade including N. bombycis, N. spodopterae, and N. sp. PX1.
• The isolate successfully parasitized Papilio machaon.

Conclusions:

• Nosema sp. PM-1 represents a distinct lineage within the "true" Nosema group.
• The isolation from Papilio machaon expands the known host range for Nosema.
• This finding highlights the potential for Nosema to infect a broader spectrum of lepidopteran species.