Mapping and Expression Analysis of a Fusarium Head Blight Resistance Gene Candidate Pleiotropic Drug Resistance 5 (PDR5) in Wheat

Fusarium head blight (FHB) caused by Fusarium graminearum is a serious disease of wheat (Triticum aestivum L.), through which grain quality losses are induced by fungal trichotecene mycotoxins such as deoxynivalenol (DON). A class of plasma membrane localized ABC transporter proteins related to the yeast PDR5 (pleiotropic drug resistance5) efflux pump seems to be responsible for partial resistance against trichothecenes in wheat. In order to develop and map a PDR5-specific marker linked to Fusarium head blight resistance in wheat, F3 and F5 generations obtained from a cross between ‘Wangshuibai’ and ‘Seri82’ were used. The analysis of nucleotide sequences of OSPDR5 revealed a high homology to the wheat EST BT009500. Among ten primer pairs developed from this PDR5-like EST, one was polymorphic between the parental lines. This PCR-based marker associated with FHB resistance in a ‘Wangshuibai’ derived mapping population. In this study, Composite Interval Mapping (CIM) analysis detected a QTL in the map interval of Xm12p17_2-Xpdr5 (consisting of the developed PDR5-like gene locus) on chromosome 6BS. This QTL accounted for up to 18% of AUDPC variation. Real-time quantitative analysis showed that wheat PDR5-like gene expression was up-regulated during the post-inoculation period of 96 hours in the spike. Our results are in agreement with the hypothesis that the PDR5-like gene may be considered as a FHB resistance gene candidate in wheat.