Given the central role of haustoria in the infection process,
several attempts have been made to purify them to a
degree suitable for proteomic and genetic analyses. Enrichment
has relied mainly on concavalin A sepharose affinity
chromatography [15, 16] and density gradient centrifugation
[17, 18]. Although both methods enrich haustoria to a degree,
they suffer from the drawback that the resulting enrichments
are contaminated with both plant material and hyphae, and it
is therefore difficult to identify haustoria proteins unequivocally,
although a subtractive approach can be used [16]. Here,
we present findings on the haustoria proteome using haustoria
that were purified to near homogeneity by immunoprecipitation
with monoclonal antibodies prepared specifically to
haustoria of P. triticina. We have used a high-resolution, high
mass accuracy mass spectrometer to analyze tryptic peptides
derived from these haustoria and have tentatively identified
1192 proteins with two or more peptides matched (p < 0.05).
Using bioinformatics-based algorithms and characteristics of
known effectors, 140 effector protein candidates have been
tentatively identified.