Alkaloid Synthetic Pathway: Noscapine, a nonaddictive alkaloid found in the opium poppy, can be used as a cough suppressant and a tubulin-binding antitumor agent. Winzer et al. (p. 1704 , published online 31 May; see the Perspective by DellaPenna and O'Connor ) found that a cluster of 10 genes were key to the production of noscapine. Poppies homozygous for this gene cluster produced high levels of noscapine, heterozygous poppies produced low levels of noscapine, and those poppies lacking the gene cluster produced no noscapine. Silencing individual genes in turn and analyzing the accumulation of intermediate metabolites allowed the biosynthetic pathway of noscapine to be elucidated.

Potatoes destined for crisping are normally stored above 8 degrees; below this glucose accumulates leading to very dark fry colors and potential acrylamide build up. Unfortunately, sprouting occurs above 4 degrees and impacts product quality, necessitating the use of sprout suppressant chemicals. Therefore, a goal of breeders is to develop potatoes with excellent fry color, which is maintained under storage below 8 degrees. Genomic or marker-assisted selection offers an opportunity to improve the efficiency of potato breeding and thereby assist breeders in achieving this goal. In this study, we have accumulated fry-color data on a large population of potato lines and combined this with genotypic data to carry out a GWAS and to evaluate accuracy of genomic prediction. We were able to identify a major QTL on chromosome 10 for fry color, and predict fry color with moderate accuracy using genome-wide markers. Furthermore, our results provide evidence that it is possible to identify a small subset of SNPs for processing characteristics that can give moderate predictive ability, albeit lower than that achieved with genome-wide markers.

Zymoseptoria tritici is the causative fungal pathogen of septoria tritici blotch (STB) disease of wheat (Triticum aestivum L.) that continuously threatens wheat crops in Ireland and throughout Europe. Under favorable conditions, STB can cause up to 50% yield losses if left untreated. STB is commonly controlled with fungicides; however, a combination of Z. tritici populations developing fungicide resistance and increased restrictions on fungicide use in the EU has led to farmers relying on fewer active substances. Consequently, this serves to drive the emergence of Z. tritici resistance against the remaining chemistries. In response, the use of resistant wheat varieties provides a more sustainable disease management strategy. However, the number of varieties offering an adequate level of resistance against STB is limited. Therefore, new sources of resistance or improved stacking of existing resistance loci are needed to develop varieties with superior agronomic performance. Here, we identified quantitative trait loci (QTL) for STB resistance in the eight-founder “NIAB Elite MAGIC” winter wheat population. The population was screened for STB response in the field under natural infection for three seasons from 2016 to 2018. Twenty-five QTL associated with STB resistance were identified in total. QTL either co-located with previously reported QTL or represent new loci underpinning STB resistance. The genomic regions identified and the linked genetic markers serve as useful resources for STB resistance breeding, supporting rapid selection of favorable alleles for the breeding of new wheat cultivars with improved STB resistance.

The STORR gene fusion event is considered essential for the evolution of the promorphinan/morphinan subclass of benzylisoquinoline alkaloids (BIAs) in opium poppy as the resulting bi-modular protein performs the isomerization of (S)- to (R)-reticuline essential for their biosynthesis. Here, we show that of the 12 Papaver species analysed those containing the STORR gene fusion also contain promorphinans/morphinans with one important exception. P. californicum encodes a functionally conserved STORR but does not produce promorphinans/morphinans. We also show that the gene fusion event occurred only once, between 16.8-24.1 million years ago before the separation of P. californicum from other Clade 2 Papaver species. The most abundant BIA in P. californicum is (R)-glaucine, a member of the aporphine subclass of BIAs, raising the possibility that STORR, once evolved, contributes to the biosynthesis of more than just the promorphinan/morphinan subclass of BIAs in the Papaveraceae.

Wild potato species continue to be a rich source of genes for resistance to late blight in potato breeding. Whilst many dominant resistance genes from such sources have been characterised and used in breeding, quantitative resistance also offers potential for breeding when the loci underlying the resistance can be identified and tagged using molecular markers. In this study, F₁ populations were created from crosses between blight susceptible parents and lines exhibiting strong partial resistance to late blight derived from the South American wild species Solanum microdontum and Solanum pampasense. Both populations exhibited continuous variation for resistance to late blight over multiple field-testing seasons. High density genetic maps were created using single nucleotide polymorphism (SNP) markers, enabling mapping of quantitative trait loci (QTLs) for late blight resistance that were consistently expressed over multiple years in both populations. In the population created with the S. microdontum source, QTLs for resistance consistently expressed over three years and explaining a large portion (21–47%) of the phenotypic variation were found on chromosomes 5 and 6, and a further resistance QTL on chromosome 10, apparently related to foliar development, was discovered in 2016 only. In the population created with the S. pampasense source, QTLs for resistance were found in over two years on chromosomes 11 and 12. For all loci detected consistently across years, the QTLs span known R gene clusters and so they likely represent novel late blight resistance genes. Simple genetic models following the effect of the presence or absence of SNPs associated with consistently effective loci in both populations demonstrated that marker assisted selection (MAS) strategies to introgress and pyramid these loci have potential in resistance breeding strategies.