Identification of two thaumatin-like proteins (TLPs) in the pollination drop of hybrid yew that may play a role in pathogen defence during pollen collection.

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TypeArticle
Journal titleTree Physiology
ISSN0829-318X
Volume27
Issue12
Pages16491659; # of pages: 11
AbstractWe describe the proteomic identification of two pathogenesis-related group 5 (PR-5) proteins, an acidic thaumatin-like protein (TLP) and a basic TLP isolated from the pollination drop of hybrid yew (Taxus x media Rehder). The basic TLP (TxmTLPb) was the most abundant protein in the yew pollination drop based on protein spot size after two-dimensional electrophoresis. The acidic TLP (TxmTLPa) is also a major protein component of the yew ovular secretion and appears to be encoded by a number of mRNAs transcribed from a TLP gene family that has undergone limited sequence divergence. We have sequenced five acidic TLP-encoding cDNAs (TxmTLPa-1,2,3,4 and 5) isolated from the yew ovule that vary from each other by no more than five out of 233 amino acid residues in their predicted protein sequences. All of the cDNA variants encode TLPs possessing the 16 conserved cysteine residues and five charged amino acid side chains associated with antifungal activity. Amplification of genomic DNA with TxmTLPa primers indicated that at least 11 acidic TLPs with highly similar amino acid sequences may be expressed in yew tissues. Antibodies against TLPs confirmed the identity of TxmTLPa and TxmTLPb in the yew pollination drop and detected TLPs in the ovular secretions of four other species from three other conifer families. Our results suggest that TLPs are a conserved component of conifer ovular secretions and are involved in broad spectrum pathogen defence of ovules.
Publication date
AffiliationNRC Institute for Marine Biosciences; National Research Council Canada
Peer reviewedYes
NRC number1764
NPARC number3538077
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Record identifier13e92c4e-7634-4c72-89bd-856ec3cf130b
Record created2009-03-01
Record modified2016-05-09
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