Four enzymes control natural variation in the steroid core of cardenolides.

Unlabelled: Plants commonly produce families of structurally related metabolites with similar defensive functions. This apparent redundancy raises the question of underlying molecular mechanisms and adaptive benefits of such chemical variation. Cardenolides, a class defensive compounds found in the wallflower genus (L.

Aphid Resistance Segregates Independently of Cardenolide and Glucosinolate Content in an (Wormseed Wallflower) F2 Population.

Plants in the genus produce both glucosinolates and cardenolides as a defense mechanism against herbivory. Two natural isolates of (wormseed wallflower) differed in their glucosinolate content, cardenolide content, and their resistance to (green peach aphid), a broad generalist herbivore. Both classes of defensive metabolites were produced constitutively and were not further induced by aphid feeding.

Aphid resistance segregates independently of cardiac glycoside and glucosinolate content in an (wormseed wallflower) F2 population.

Plants in the genus produce both glucosinolates and cardiac glycosides as defense against herbivory. Two natural isolates of (wormseed wallflower) differed in their glucosinolate content, cardiac glycoside content, and resistance to (green peach aphid), a broad generalist herbivore. Both classes of defensive metabolites were produced constitutively and were not induced further by aphid feeding.

Diversity and divergence: evolution of secondary metabolism in the tropical tree genus Inga.

Plants are widely recognized as chemical factories, with each species producing dozens to hundreds of unique secondary metabolites. These compounds shape the interactions between plants and their natural enemies. We explore the evolutionary patterns and processes by which plants generate chemical diversity, from evolving novel compounds to unique chemical profiles.

Acropetal and basipetal cardenolide transport in Erysimum cheiranthoides (wormseed wallflower).

Plant specialized metabolites are often subject to within-plant transport and have tissue-specific distribution patterns. Among plants in the Brassicaceae, the genus Erysimum is unique in producing not only glucosinolates but also cardenolides. Ten cardenolides were detected with varying abundance in different tissues of Erysimum cheiranthoides L (Brassicaceae; wormseed wallflower).

Less Is More: a Mutation in the Chemical Defense Pathway of Erysimum cheiranthoides (Brassicaceae) Reduces Total Cardenolide Abundance but Increases Resistance to Insect Herbivores.

Erysimum cheiranthoides L (Brassicaceae; wormseed wallflower) accumulates not only glucosinolates, which are characteristic of the Brassicaceae, but also abundant and diverse cardenolides. These steroid toxins, primarily glycosylated forms of digitoxigenin, cannogenol, and strophanthidin, inhibit the function of essential Na/K-ATPases in animal cells. We screened a population of 659 ethylmethanesulfonate-mutagenized E.

Phenolics lie at the centre of functional versatility in the responses of two phytochemically diverse tropical trees to canopy thinning.

Saplings in the shade of the tropical understorey face the challenge of acquiring sufficient carbon for growth as well as defence against intense pest pressure. A minor increase in light availability via canopy thinning may allow for increased investment in chemical defence against pests, but it may also necessitate additional biochemical investment to prevent light-induced oxidative stress. The shifts in secondary metabolite composition that increased sun exposure may precipitate in such tree species present an ideal milieu for evaluating the potential of a single suite of phenolic secondary metabolites to be used in mitigating both abiotic and biotic stressors.

Metabolome-Scale Genome-Wide Association Studies Reveal Chemical Diversity and Genetic Control of Maize Specialized Metabolites.

Cultivated maize () has retained much of the genetic diversity of its wild ancestors. Here, we performed nontargeted liquid chromatography-mass spectrometry metabolomics to analyze the metabolomes of the 282 maize inbred lines in the Goodman Diversity Panel. This analysis identified a bimodal distribution of foliar metabolites.

Herbivores as drivers of negative density dependence in tropical forest saplings.

Ecological theory predicts that the high local diversity observed in tropical forests is maintained by negative density-dependent interactions within and between closely related plant species. By using long-term data on tree growth and survival for coexisting (Fabaceae, Mimosoideae) congeners, we tested two mechanisms thought to underlie negative density dependence (NDD): competition for resources and attack by herbivores. We quantified the similarity of neighbors in terms of key ecological traits that mediate these interactions, as well as the similarity of herbivore communities.

Tracking of Host Defenses and Phylogeny During the Radiation of Neotropical -Feeding Sawflies (Hymenoptera; Argidae).

Coevolutionary theory has long predicted that the arms race between plants and herbivores is a major driver of host selection and diversification. At a local scale, plant defenses contribute significantly to the structure of herbivore assemblages and the high alpha diversity of plants in tropical rain forests. However, the general importance of plant defenses in host associations and divergence at regional scales remains unclear.

Chemocoding as an identification tool where morphological- and DNA-based methods fall short: Inga as a case study.

The need for species identification and taxonomic discovery has led to the development of innovative technologies for large-scale plant identification. DNA barcoding has been useful, but fails to distinguish among many species in species-rich plant genera, particularly in tropical regions. Here, we show that chemical fingerprinting, or 'chemocoding', has great potential for plant identification in challenging tropical biomes.