Suppressed recombination and unique candidate genes in the divergent haplotype encoding Fhb1, a major Fusarium head blight resistance locus in wheat

Fhb1 is a prominent Fusarium head blight resistance locus of wheat, which has been successfully introgressed in adapted breeding material, where it confers a significant increase in overall resistance to the causal pathogen Fusarium graminearum and the fungal virulence factor and mycotoxin deoxynivalenol. The Fhb1 region has been resolved for the susceptible wheat reference genotype Chinese Spring, yet the causal gene itself has not been identified in resistant cultivars. Here, we report the establishment of a 1 Mb contig embracing Fhb1 in the donor line CM-82036. Sequencing revealed that the region of Fhb1 deviates from the Chinese Spring reference in DNA size and gene content, which explains the repressed recombination at the locus in the performed fine mapping. Differences in genes expression between near-isogenic lines segregating for Fhb1 challenged with F. graminearum or treated with mock were investigated in a time-course experiment by RNA sequencing. Several candidate genes were identified, including a pathogen-responsive GDSL lipase absent in susceptible lines. The sequence of the Fhb1 region, the resulting list of candidate genes, and near-diagnostic KASP markers for Fhb1 constitute a valuable resource for breeding and further studies aiming to identify the gene(s) responsible for F. graminearum and deoxynivalenol resistance.(VLID)141383

Identification of multiple root disease resistant wheat germplasm against cereal nematodes and dryland root rot and their validation in regions of economic importance

História da literatura portuguesa coordenada por Giulia Lanciani - primeiras páginas de um total pp. 7-108)História literária do século XVIII portuguêsGoverno de Portuga

Correlative analysis of grain boundary precipitates in Ni-based superalloy René 41

Both hot workability and in-service mechanical properties of Ni-based superalloys are strongly influenced by the presence of secondary phases precipitated within the matrix and at grain boundaries. Due to its remarkably high contents of alloying elements, Ni-based superalloy René 41 forms various precipitate phases at grain boundaries, including but not limited to various carbides and γ’ precipitates, and this may lead to grain boundary cracking. Better knowledge of the nature of these precipitates at different temperatures will enable manufacturing of René 41 aerospace parts with higher yield and better in-service properties. Limitations of conventional electron microscopy methods have previously impeded progress at this front. Previous studies on grain boundary precipitation in René 41 indicate the co-existence of two dominant types of grain boundary carbides, M6C at temperatures up to 1147 °C and M23C6 below 980 °C. However, recent state-of-the-art thermodynamic simulations indicate that M6C is stable over a much wider temperature range. We propose a novel correlative approach using both convergent beam electron diffraction (CBED) and site-specific atom probe microscopy (APM) to distinguish grain boundary carbides in René 41 unambiguously. While CBED reveals space groups, APM enables chemical analyses with near atomic resolution in 3D. Our correlative microscopy combined with thermodynamic simulations confirms the presence of both M6C and M23C6 after annealing at 900 °C while only M6C is present at 1100 °C

Identification of multiple root disease resistant wheat germplasm against cereal nematodes and dryland root rot and their validation in regions of economic importance

Soil Borne Pathogens (SBPs), including dryland cereal root rots and cereal nematodes are a major constraint to cereal production worldwide, particularly where cereals dominate rotations, and sub-optimal growing conditions and or cultural practices are common