Performance of an herbivorous leaf beetle (Phratora vulgatissima) on Salix F2 hybrids: the importance of phenolics.

The genotype of the plant determines, through the expression of the phenotype, how well it is suited as food for herbivores. Since hybridization often results in profound genomic alterations with subsequent changes in phenotypic traits, it has the potential to significantly affect plant-herbivore interactions. In this study, we used a population of F2 hybrids that originated from a cross between a Salix viminalis and a Salix dasyclados genotype, which differed in both phenolic content and resistance to the herbivorous leaf beetle Phratora vulgatissima. We screened for plants that showed a great variability in leaf beetle performance (i.e., oviposition and survival). By correlating leaf phenolics to the response of the herbivores, we evaluated the importance of different phenolic compounds for Salix resistance to the targeted insect species. The performance of P. vulgatissima varied among the F2 hybrids, and two patterns of resistance emerged: leaf beetle oviposition was intermediate on the F2 hybrids compared to the parental genotypes, whereas leaf beetle survival demonstrated similarities to one of the parents. The findings indicate that these life history traits are controlled by different resistance mechanisms that are inherited differently in the hybrids. Salicylates and a methylated luteolin derivative seem to play major roles in hybrid resistance to Phratora vulgatissima. Synergistic effects of these compounds, as well as potential threshold concentrations, are plausible. In addition, we found considerable variation in both distributions and concentrations of different phenolics in the F2 hybrids. The phenolic profiles of parental genotypes and F2 hybrids differed significantly (e.g., novel compounds appeared in the hybrids) suggesting genomic alterations with subsequent changes in biosynthetic pathways in the hybrids.

Genetically modified (GM) late blight-resistant potato and consumer attitudes before and after a field visit.

Late blight, caused by Phytophthora infestans, is the most devastating disease in potato production. Here, we show full late blight resistance in a location with a genetically diverse pathogen population with the use of GM potato stacked with three resistance (R) genes over three seasons. In addition, using this field trials, we demonstrate that in-the-field intervention among consumers led to change for more favorable attitude generally toward GM crops.

Constitutive and herbivore-induced systemic volatiles differentially attract an omnivorous biocontrol agent to contrasting Salix clones.

While carnivores are known to be attracted to herbivore-induced plant volatiles, little is known about how such volatiles may affect the behaviour of omnivorous predators that may use both plants and herbivores as food. Here, we examine how systemically produced plant volatiles, in response to local herbivore damage, differentially attract a key omnivorous predator, Anthocoris nemorum (Heteroptera: Anthocoridae), to single clones of three species of Salix: S. viminalis, S. dasyclados and S. cinerea. The profiles of the plant volatiles produced were found to vary among Salix clones and between herbivore-damaged and intact plants. Anthocoris nemorum was attracted to the volatiles released from undamaged plants of all three species, but most strongly to a native S. cinerea clone. Plants damaged by the herbivorous leaf beetle Phratora vulgatissima (Coleoptera: Chrysomelidae) were generally more attractive than undamaged plants, with A. nemorum responding to systemic changes in the damaged plants where the experimental design specifically excluded volatiles released from the actual site of damage. When comparing damaged plants, the S. dasyclados clone was more attractive to A. nemorum than the S. viminalis clone-a somewhat surprising result since this Salix clone is considered relatively resistant to P. vulgatissima, and hence offers a limited amount of prey. Our experiments highlight that both constitutive and induced plant volatiles play a role in omnivore attraction, and this emphasizes the importance of considering odours of released volatiles when cropping and breeding Salix for increased resistance to herbivores.

Swedish farmers attitudes, expectations and fears in relation to growing genetically modified crops.

This study evaluates a survey about Swedish farmers' attitude towards genetically modified (GM) crops, and their perception concerning potential benefits and drawbacks that cropping of an insect resistant (IR) GM variety would involve. The questions were "tick a box" choices, included in a yearly omnibus survey sent to 1000 Swedish farmers (68% response rate). The results showed that a majority of the farmers were negative, although almost one third claimed to be neutral to GM crops. The farmers recognized several benefits both in terms of agricultural production and for the environment, but they were also highly concerned about the consumers' unwillingness to buy GM products. Farmers perceived an increase in yield, but nearly as many farmers thought that there would be no benefits with growing an IR GM crop. Several differences in hopes and concerns of the farmers surveyed were revealed when they were divided in positive, neutral and negative groups. Farmers negative to GM were more concerned than positive farmers about IR GM crops being dangerous for humans, livestock or other organisms to consume. GM-positive farmers seemed to be most concerned about potential problems with growing a marketable crop and expensive seeds, but saw a reduced health risk to the grower, due to less use of pesticides, as a possible benefit. The results among the GM-neutral farmers were in most cases closely related to the positive farmers' choices, implying that they believe that there are advantages with growing an IR GM crop, but also fear potential drawbacks. This general uncertainty about GM IR crops may prevent them from accepting the new technology.

Does pea lectin expressed transgenically in oilseed rape (Brassica napus) influence honey bee (Apis mellifera) larvae?

The European honey bee (Apis mellifera) is important both for pollination and for honey production. Pollen is the major protein source for bees, which exposes them directly to changes in pollen quality e.g. through genetic engineering. In order to create a worst case scenario regarding pea lectin (PSL) expressed transgenically in oilseed rape anthers and pollen, the maximum amount of dried pollen that could be mixed in an artificial diet without negatively affecting larval performance (1.5% w/w) was fed to bee larvae. Pollen from two transgenic plant lines expressing PSL up to 1.2% of total soluble protein and pollen from one non-transgenic line was added to the same diet and used as a pollen control. When these three pollen diets and the control diet (without added pollen) were compared, no negative effect from the pollen of the transgenic plants could be detected on larval mortality, weight, or development time. An increased weight and a reduced developmental time were recorded for larvae on all diets containing pollen when compared to the diet without pollen.