Herbivore-damaged plants release complex mixtures of volatiles that attract natural enemies of the herbivore. To study the relevance of individual components of these mixtures for predator attraction, we manipulated herbivory-induced volatiles through genetic engineering. Metabolic engineering of terpenoids, which dominate the composition of many induced plant volatile bouquets, holds particular promise. By switching the subcellular localization of the introduced sesquiterpene synthase to the mitochondria, we obtained transgenic Arabidopsis thaliana plants emitting two new isoprenoids. These altered plants attracted carnivorous predatory mites (Phytoseiulus persimilis) that aid the plants' defense mechanisms.

Background: Bread wheat (Triticum aestivum) is an important staple food. However, wheat gluten proteins cause celiac disease (CD) in 0.5 to 1% of the general population. Among these proteins, the α-gliadins contain several peptides that are associated to the disease.

BackgroundProduction of pharmaceuticals in plants provides an alternative for chemical synthesis, fermentation or natural sources. Nicotiana benthamiana is deployed at commercial scale for production of therapeutic proteins. Here the potential of this plant is explored for rapid production of precursors of artemisinin, a sesquiterpenoid compound that is used for malaria treatment.Methodology/Principal FindingsBiosynthetic genes leading to artemisinic acid, a precursor of artemisinin, were combined and expressed in N. benthamiana by agro-infiltration. The first committed precursor of artemisinin, amorpha-4,11-diene, was produced upon infiltration of a construct containing amorpha-4,11-diene synthase, accompanied by 3-hydroxy-3-methylglutaryl-CoA reductase and farnesyl diphosphate synthase. Amorpha-4,11-diene was detected both in extracts and in the headspace of the N. benthamiana leaves. When the amorphadiene oxidase CYP71AV1 was co-infiltrated with the amorphadiene-synthesizing construct, the amorpha-4,11-diene levels strongly decreased, suggesting it was oxidized. Surprisingly, no anticipated oxidation products, such as artemisinic acid, were detected upon GC-MS analysis. However, analysis of leaf extracts with a non-targeted metabolomics approach, using LC-QTOF-MS, revealed the presence of another compound, which was identified as artemisinic acid-12-β-diglucoside. This compound accumulated to 39.5 mg.kg−1 fwt. Apparently the product of the heterologous pathway that was introduced, artemisinic acid, is further metabolized efficiently by glycosyl transferases that are endogenous to N. benthamiana.Conclusion/SignificanceThis work shows that agroinfiltration of N. bentamiana can be used as a model to study the production of sesquiterpenoid pharmaceutical compounds. The interaction between the ectopically introduced pathway and the endogenous metabolism of the plant is discussed.

Background: Gluten proteins can induce celiac disease (CD) in genetically susceptible individuals. In CD patients gluten-derived peptides are presented to the immune system, which leads to a CD4 + T-cell mediated immune response and inflammation of the small intestine. However, not all gluten proteins contain T-cell stimulatory epitopes. Gluten proteins are encoded by multigene loci present on chromosomes 1 and 6 of the three different genomes of hexaploid bread wheat (Triticum aestivum) (AABBDD).

The results suggest that additional regulator elements upstream of the promoter region used may specifically repress expression in the aleurone cell layer. Observed differences in expression regulator motifs between the alpha-gliadin genes on the different genomes (A and B) of bread wheat leads to a better understanding how alpha-gliadin expression can be controlled.

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Micropropagation techniques have been widely applied in globe artichoke (C. cardunculus L. var. scolymus), however, efficient protocols for the establishment of in vitro callogenesis and organogenesis, a pre-requisite for Agrobacteriummediated genetic transformation, have not been set up so far. We developed an efficient protocol for callus induction from leaf explants of three globe artichoke genotypes of the varietal type 'Romanesco'; after just one week culture callus formed with an efficiency close to 100%. Leaf explants were transformed with Agrobacterium tumefaciens Agl0 01-124 strain, harboring the binary vector pCAMBIA 2301 with the gene marker GUS, under the control of CaMV 35S promoter. After two weeks, about 30% of the calli obtained from infected leaf explants were positive to GUS assay.

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