title: Probing allocrite preferences of 2 naturally occurring variants of the wheat LR34 ABC transporter.
abstract: For almost a century, the wheat Lr34 gene has conferred durable resistance against fungal rust diseases. While sequence homology predicts a putative ATP binding cassette transporter, the molecules that are transported (allocrites) by the encoded LR34 variants, and any associated mechanism of resistance, remain enigmatic. Here, the in vitro transport characteristics of 2 naturally occurring Lr34 variants (that differ in their ability to mediate disease resistance; Lr34sus and Lr34res) are investigated. Initially, a method to express and purify recombinant LR34Sus and LR34Res pseudo half-molecules from Saccharomyces cerevisiae, is described. Subsequently, a semi-targeted chlorophyll catabolite (CC) extraction from Lr34res-expressing wheat plants was performed based on previous reports highlighting increased accumulation of CCs in Lr34res-expressing flag leaves. Following partial biochemical characterization, this extract was applied to an LR34 in vitro proteoliposome transport assay. Mass spectroscopic analyses of transported metabolites revealed that LR34Sus imported a wheat metabolite of 618 Da and that the LR34Res transporter did not. While the identity of the LR34Sus transported metabolite remains to be confirmed and any allocrites of LR34Res remain to be detected, this work demonstrates that these variants have different allocrite preferences, a finding that may be relevant to the mechanism of disease resistance.
authors: a National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada.
authors: Nandhakishore
authors: N
authors: Rajagopalan
authors: b National Research Council of Canada, 6100 Royalmount Avenue, Montreal, QC H4P 2R2, Canada.
authors: Annamaria
authors: A
authors: Halasz
authors: a National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada.
authors: Yuping
authors: Y
authors: Lu
authors: a National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada.
authors: Enwu
authors: E
authors: Liu
authors: b National Research Council of Canada, 6100 Royalmount Avenue, Montreal, QC H4P 2R2, Canada.
authors: Fanny
authors: F
authors: Monteil-Rivera
authors: a National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada.|c Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.
authors: Michele C
authors: MC
authors: Loewen
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D007113:Immunity, Innate / Q000276:immunology*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D010940:Plant Proteins; D002734:Chlorophyll
keywords: PDR/ABCG transporter; adult plant resistance (APR); leaf rust; leaf tip necrosis (LTN); nécrose des extrémités foliaires; rouille de la feuille; résistance des plants adultes; transporteur PDR/ABCG