Journal Article

Homoserine and asparagine are host signals that trigger in planta expression of a pathogenesis gene in Nectria haematococca

Guo, W, Rogers, L.M, Yang, Z, Song, Y, Kolattukudy, P.E

2005

Overview

Some pathogenesis-related genes are expressed in fungi only when the pathogen is in the host, but the host signals that trigger these gene expressions have not been identified. Virulent Nectria haematococca infects pea plants and requires either pelA, which is induced by pectin, or pelD, which is induced only in planta. However, the host signal(s) that trigger pelD expression was unknown. Here we report the isolation of the host signals and identify homoserine and asparagine, two free amino acids found in uniquely high levels in pea seedlings, as the pelD-inducing signals. N. haematococca has evolved a mechanism to sense the host tissue environment by using the high levels of two free amino acids in this plant, thereby triggering the expression of pelD to assist the pathogenic process.

• Publisher: National Academy of Sciences,National Acad Sciences
• Subject: Amino acids / asparagine / Asparagine - metabolism / Biological Sciences / Botany / Enzymes / fungal diseases of plants / Fungal genes / Fungi - enzymology / Fungi - genetics / Fungi - pathogenicity / Fusarium eumartii / Gels / Gene expression / gene expression regulation / genes / homoserine / Homoserine - metabolism / Host-Parasite Interactions - genetics / Host-Parasite Interactions - physiology / host-pathogen relationships / Infections / Nectria haematococca / Organisms, Genetically Modified / Pathogenesis / Pathogens / Peas / pectate lyase / pelD gene / pelD promoter / Pisum / Pisum sativum / Pisum sativum - metabolism / Pisum sativum - microbiology / plant pathogenic fungi / Polysaccharide-Lyases - biosynthesis / Polysaccharide-Lyases - genetics / promoter regions / Promoter Regions, Genetic / Seedlings / Seedlings - metabolism / Seedlings - microbiology / Water filtration