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The necrotrophic fungus Parastagonospora nodorum is an important pathogen of one of the world’s most economically important cereal crops, wheat (Triticum aestivum L.). P. nodorum produces necrotrophic protein effectors that mediate host cell death, providing nutrients for continuation of the infection process. The recent discovery of pathogen effectors has revolutionized disease resistance breeding for necrotrophic diseases in crop species, allowing often complex genetic resistance mechanisms to be broken down into constituent parts. To date, three effectors have been identified in P. nodorum. Here we use the effector, SnTox1, to screen 642 progeny from an eight-parent multiparent advanced generation inter-cross (i.e., MAGIC) population, genotyped with a 90,000-feature single-nucleotide polymorphism array. The MAGIC founders showed a range of sensitivity to SnTox1, with transgressive segregation evident in the progeny. SnTox1 sensitivity showed high heritability, with quantitative trait locus analyses fine-mapping the Snn1 locus to the short arm of chromosome 1B. In addition, a previously undescribed SnTox1 sensitivity locus was identified on the long arm of chromosome 5A, termed here QSnn.niab-5A.1. The peak single-nucleotide polymorphism for the Snn1 locus was converted to the KASP genotyping platform, providing breeders and researchers a simple and cheap diagnostic marker for allelic state at Snn1.

The calanoid copepod Acartia tonsa has been recommended as a marine organism for ecotoxicological tests due to its wide distribution, short life cycle and high productivity. This species is used in acute and chronic toxicity tests to assess water and sediment quality; egg hatching success and the survival of the first larval stages are considered endpoints. Toxicity test protocols require a large number of organisms and an appropriate culture system. Eggs stored under conditions that delay hatching could ensure sufficient quantities of biological materials for ecotoxicological tests. In the current study early-spawned eggs were stored at 3 °C (±1) up to 240 days and their hatching success was evaluated on a monthly basis. Our results showed that the percentage of hatching success for eggs stored for 30 days was >80 % and decreased by about 8 % for every 20 days of storage, up to 120 days. A further increase of time in cold storage brought about a significant reduction, in statistical term, of hatching success compared with the control group (43.69 ± 22.19 %). Almost 50 % of eggs hatched or died during the cold storage period, with more than 80 % lost after periods longer than 150 days. To verify the suitability of stored eggs for toxicity test, 48 h acute tests were performed using nickel chloride as a referent toxicant. Eggs stored for 30, 60, 90 and 120 days gave EC50 values ranging from 0.130 to 0.221 mg L(-1), similar to the value recorded for early-spawned eggs, suggesting that these eggs can be used for ecotoxicological tests. Our results open new possibilities for a wider use of the Mediterranean strain of A. tonsa copepod for ecotoxicological tests.