ABCDEFGHIJKLMNOPQRSTUVWXYZ

Peanut root tip with stained root-knot nematodes (Meloidogyne arenaria) inside.  Root-knot nematodes are plant pathogens that are classified as biotrophs.

Intercellular mycelia and haustoria of Bremia lactuca, the plant-pathogenic cause of lettuce downy mildew disease.  Species of the genus Bremia are classified as biotrophic plant pathogens.

Definition

A biotroph is an organism that can live and multiply only on another living organism (see necrotroph for an antonym).

Discussion

Biotrophs are also referred to as obligate parasites.

Examples of common biotrophs include:

1. Plant pathogenic viruses, viroids

2. Some plant pathogenic fungi

3. Plant pathogenic nematodes