PMC

Proton symport model for nutrient transport across the haustorial plasma membrane, supplying glucose and amino acids to biotrophic fungi. 1, Protons are supplied by haustorial plasma membrane H⁺-ATPase (); 2, Amino acid transporter (); 3, Glucose/fructose transporter described by Voegele et al. (). Redrawn from Hahn et al. ().

Haustorial complex, a specialized feeding organ of biotrophic fungal parasites of plants. To move from host cell to fungus, nutrients must traverse the extrahaustorial membrane, the extrahaustorial matrix, the haustorial wall, and the haustorial plasma membrane. A neckband seals the extrahaustorial matrix from the plant cell wall region so that the matrix becomes a unique, isolated, apoplast-like compartment. The haustorium connects to intercellular fungal hyphae by way of a haustorial mother cell. Evidence from Voegele et al. () indicates that a proton symport system in the haustorial plasma membrane drives sugar transport from plant to parasite. (A) Transmission electron micrograph of a flax rust haustorium [Reproduced with permission from ref. (Copyright 1972, NRC Research Press)]. (Bar, 1 μm.) (B) Drawing showing key features of the fungal haustorium.