Genetic characterization of QTL associated with resistance to Fusarium head blight in a doubled-haploid spring wheat population.

Fusarium head blight (FHB) is one of the most important fungal wheat diseases worldwide. Understanding the genetics of FHB resistance is the key to facilitating the introgression of different FHB resistance genes into adapted wheat. The objectives of the present study were to detect and map quantitative trait loci (QTL) associated with FHB resistance genes and characterize the genetic components of the QTL in a doubled-haploid (DH) spring wheat population using both single-locus and two-locus analysis. A mapping population, consisting of 174 DH lines from the cross between DH181 (resistant) and AC Foremost (susceptible), was evaluated for type I resistance to initial infection during a 2-year period in spray-inoculated field trials, for Type II resistance to fungal spread within the spike in 3 greenhouse experiments using single-floret inoculation, and for resistance to kernel infection in a 2001 field trial. One-locus QTL analysis revealed 7 QTL for type I resistance on chromosome arms 2DS, 3AS, 3BS, 3BC (centromeric), 4DL, 5AS, and 6BS, 4 QTL for type II resistance on chromosomes 2DS, 3BS, 6BS, and 7BL, and 6 QTL for resistance to kernel infection on chromosomes 1DL, 2DS, 3BS, 3BC, 4DL, and 6BS. Two-locus QTL analysis detected 8 QTL with main effects and 4 additive by additive epistatic interactions for FHB resistance and identified novel FHB resistance genes for the first time on chromosomes 1DL, 4AL, and 4DL. Neither significant QTL by environment interactions nor epistatic QTL by environment interactions were found for either type I or type II resistance. The additive effects of QTL explained most of the phenotypic variance for FHB resistance. Marker-assisted selection for the favored alleles at multiple genomic regions appears to be a promising tool to accelerate the introgression and pyramiding of different FHB resistance genes into adapted wheat genetic backgrounds.     

Open field stress and neurons containing calcium-binding proteins in the piriform cortex of the rat.

In the present study we wanted to check whether the expression of the c-Fos protein (the marker of cellular activity) appears in cells containing calcium-binding proteins (CaBPs) in animals exposed to the open field test. Eight adult Wistar rats were examined. In the first step the open field test was applied throughout 10 minutes. After perfusional fixation brains were frozen and cut on the cryostat in the coronal plane and stained with the standard immunohistochemical method. Sections were double stained for c-Fos and CaBPs: parvalbumin (PV), calbindin (CB), calretinin (CR). c-Fos positive cells were localized predominantly in layers II and III of the piriform cortex (PC). The double labeling study showed that neurons containing CaBPs are rarely c-Fos-immunoreactive. Often PV-positive and CB-positive fibers surround c-Fos-positive neurons in layers II and III in a form of a basket. It seems that cells containing CaBPs are not directly involved in the response to aversive stimuli but cells containing those calcium-binding proteins might influence directly c-Fos positive neurons of PC.