Labyrinthula

The genus Labyrinthula, also known as net slime molds, is part of the protist group Labyrinthulomycetes and contains thirteen species.

The major feature of this genus is the formation of an ectoplasmic net secreted by specialized organelles called bothrosomes which surrounds the colony, which is also used by Labyrinthula for moving.

The interest in Labyrinthula arose as it has been identified as the cause of the "wasting disease", which led to the death of more than 90% of the seagrass population of the North Atlantic coast in the early 1930s.

An epidemic happened in the 1930s in the North American and European coasts, killing over 90% of the seagrass (Zostera marina) population.

[3] The general morphology of the cell contain one central nucleus, the smooth endoplasmatic reticulum, mitochondria with tubular cristae, numerous lipid-composed granules and two large Golgi complexes.

[11] The defining characteristic of the genera Labyrinthula is the formation of an ectoplasmic net around the cells and embedding the whole colony.

The ectoplasmic net is secreted and attached to the cell by specialized organelles called segenetosome or bothrosomes.

By forming long filaments, the ectoplasmic net allows the colony to attach to surfaces and it secretes digestive enzymes for absorptive nutrition.

Some features of their binary fission are the de novo synthesis of the bothrosome and the cytokinesis, that occurs by vesicle accumulation and fusion.

[10] Labyrinthula have awoken the interest of scientists by being the cause of the "wasting disease" of the seagrass on the North American and European coasts in the 1930s.

Pathogenesis may be triggered by biotic or abiotic stress of the higher organism, like a large increase in temperature or a decrease in light exposure for example.

[17] The most famous parasitic symbiont is L. zosterae, which colonizes marine seagrasses referring to the event mentioned above.

Typical features of the "wasting disease" are a discolouration of the leaves, due to the destruction of the chloroplasts in epidermis, mesophyll and lesion formation.

It has been identified by the Koch's postulates as responsible for the "rapid blight" killing infected turf grasses.