Genome sequencing reveals the evolution and pathogenic mechanisms of the wheat sharp eyespot pathogen Rhizoctonia cerealis

The necrotrophic fungus Rhizoctonia cerealis is the causal agent of devastating diseases of cereal crops including wheat(Triticum aestivum).We present a high-quality genome assembly of R.cerealis Rc207,a virulent strain causing wheat sharp eyespot.The assembly(56.36 Mb)is composed of 17.87%repeat sequences and 14,433 predicted protein-encoding genes.The Rc207 genome encodes a large and diverse set of genes involved in pathogenicity,especially rich in those encoding secreted proteins,carbohydrateactive enzymes(CAZymes),peptidases,nucleases,cytochrome P450,and secondary metabolismassociated enzymes.Most secretory protein-encoding genes,including CAZymes,peroxygenases,dehydrogenases,and cytochrome P450,were up-regulated during fungal infection of wheat.We identified 831 candidate secretory effectors and validated the functions of 10 up-regulated candidate effector proteins.Of them,nine were confirmed as necrotrophic pathogen’s effectors promoting fungal infection.Abundant potential mobile or plastic genomic regions rich in repeat sequences suggest their roles in fungal adaption and virulence-associated genomic evolution.This study provides valuable resources for further comparative and functional genomics on important fungal pathogens,and provides essential tools for development of effective disease control strategies.

Microstructure and texture in an extruded Mg-Al-Ca-Mn flat-oval tube

In the present study,mechanical property,microstructure and texture of an extruded Mg–1.0Al–1.5Ca–1.0Mn(wt.%)flat-oval tube in both the flat and the oval regions were systematically studied.Our results show that there exists a great difference in microstructure and texture between the flat and the oval regions.Both the flat and the oval regions have fine DRXed grains of 3–4μm,while more row stacked grains are observed in the flat region.A large number of fine particles with a size of about 0.5μm are dispersed in both the grain boundary and grain interior.The particles exhibit a uniform distribution in the oval region,while they tend to aggregate into bands along the extrusion direction(ED)in the flat region.The texture in the oval region is similar to that in extruded Mg rods with a preferred distribution of prismatic planes and random distribution of(0002)poles around the ED,while that in the flat region is close to that in extruded sheets containing two texture components,<0002>//normal direction(ND)and<0002>//transverse direction(TD).A high fraction of<0002>//TD component,about 52–62%,is observed in the flat region.The flat region has a tensile yield strength of 254 MPa,an ultimate tensile strength of 290 MPa and an elongation to failure of 4.3%.