Very-long-chain aldehydes promote in vitro prepenetration processes of Blumeria graminis in a dose- and chain length-dependent manner.
Surface properties of aerial plant organs have been shown to affect the interaction of fungal plant pathogens and their hosts. Conidial germination and differentiation - the so-called prepenetration processes - of the barley powdery mildew fungus (Blumeria graminis f. sp. hordei) are known to be triggered by n-hexacosanal (C(26)-aldehyde), a minor constituent of barley leaf wax. In order to analyze the differentiation-inducing capabilities of typical aldehyde wax constituents on conidia of wheat and barley powdery mildew, synthetic even-numbered very-long-chain aldehydes (C(22)-C(30)) were assayed, applying an in vitro system based on Formvar(®)/n-hexacosane-coated glass slides. n-Hexacosanal was the most effective aldehyde tested. Germination and differentiation rates of powdery mildew conidia increased with increasing concentrations of very-long-chain aldehydes. Relative to n-hexacosanal, the other aldehyde compounds showed a gradual decrease in germination- and differentiation-inducing capabilities with both decreasing and increasing chain length. In addition to n-hexacosanal, several other ubiquitous very-long-chain aldehyde wax constituents were capable of effectively stimulating B. graminis prepenetration processes in a dose- and chain length-dependent manner. Other wax constituents, such as n-alkanes, primary alcohols (with the exception of n-hexacosanol), fatty acids and alkyl esters, did not affect fungal prepenetration.
Hansjakob
Anton
A
Universität Würzburg, Julius-von-Sachs-Institut für Biowissenschaften, Lehrstuhl für Botanik II, Julius-von-Sachs-Platz 3, D-97082 Würzburg, Germany.
Bischof
Sebastian
S
Bringmann
Gerhard
G
Riederer
Markus
M
Hildebrandt
Ulrich
U
D000447:Aldehydes / Q000737:chemistry* / Q000494:pharmacology*; D001203:Ascomycota / Q000166:cytology / Q000187:drug effects* / Q000472:pathogenicity*; D005227:Fatty Acids / Q000494:pharmacology; D005233:Fatty Alcohols / Q000494:pharmacology*; D018525:Germination / Q000187:drug effects; D001467:Hordeum / Q000187:drug effects / Q000382:microbiology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D013172:Spores, Fungal / Q000166:cytology / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D014908:Triticum / Q000187:drug effects / Q000382:microbiology; D014885:Waxes / Q000378:metabolism
D000447:Aldehydes; D005227:Fatty Acids; D005233:Fatty Alcohols; D014885:Waxes; C051942:1-hexacosanol