Systemin and jasmonic acid regulate constitutive and herbivore-induced systemic volatile emissions in tomato, Solanum lycopersicum.

Transgenic tomato (Solanum lycopersicum) plants that overexpress the Prosystemin gene (35S::PS) and plants with a mutation in the JA biosynthetic pathway (def1) are known to exhibit a constitutive or reduced wound response, respectively. Here it is demonstrated that several independent 35S::PS lines emit high levels of specific volatiles in addition to increased accumulation of proteinase inhibitors (PIs). Furthermore, the temporal dynamics of systemically induced volatile compounds including green-leaf volatiles, terpenes, and shikimic acid-derivatives from 35S::PS and def1 plants in response to herbivore wounding and treatment with jasmonic acid (JA) are described.

Production of the phytohormone indole-3-acetic acid by estuarine species of the genus Vibrio.

Strains of Vibrio spp. isolated from roots of the estuarine grasses Spartina alterniflora and Juncus roemerianus produce the phytohormone indole-3-acetic acid (IAA). The colorimetric Salkowski assay was used for initial screening of IAA production.

Tomato MAPKs LeMPK1, LeMPK2, and LeMPK3 function in the systemin-mediated defense response against herbivorous insects.

Systemin is a wound-signaling peptide that mediates defenses of tomato plants against herbivorous insects. Perception of systemin by the membrane-bound receptor SR160 results in activation of MAPKs, synthesis of jasmonic acid (JA), and expression of defense genes. To test the function of MAPKs in the response to systemin, we used virus-induced gene silencing (VIGS) in plants that overexpress the systemin precursor prosystemin (35S::prosys plants).

Volatile emissions from an odorous plant in response to herbivory and methyl jasmonate exposure.

Induced volatile terpenes have been commonly reported among diverse agricultural plant species, but less commonly investigated in odorous plant species. Odorous plants synthesize and constitutively store relatively large amounts of volatiles, and these may play a role in defense against herbivores. We examined the effect of herbivory and methyl jasmonate (MeJA) exposure on the release of volatile organic compounds (VOCs) in the marsh elder, Iva frutescens, which contains numerous constitutive VOCs, mainly mono- and sesquiterpenes.

Spectroscopic characterization of the ferric states of Amphitrite ornata dehaloperoxidase and Notomastus lobatus chloroperoxidase: His-ligated peroxidases with globin-like proximal and distal properties.

Amphitrite ornata dehaloperoxidase (DHP) and Notomastus lobatus chloroperoxidase (NCPO) catalyze the peroxide-dependent dehalogenation of halophenols and halogenation of phenols, respectively. Both enzymes have histidine (His) as their proximal heme iron ligand. Crystallographic examination of DHP revealed that it has a globin fold [M.

Development of gypsy moth larvae feeding on red maple saplings at elevated CO2 and temperature.

Predicted increases in atmospheric CO(2) and global mean temperature may alter important plant-insect associations due to the direct effects of temperature on insect development and the indirect effects of elevated temperature and CO(2) enrichment on phytochemicals important for insect success. We investigated the effects of CO(2) and temperature on the interaction between gypsy moth (Lymantria dispar L.) larvae and red maple (Acer rubrum L.

THE EVOLUTION OF CARBON ALLOCATION TO PLANT SECONDARY METABOLITES: A GENETIC ANALYSIS OF COST IN DIPLACUS AURANTIACUS.

Diplacus aurantiacus contains large amounts of a leaf phenolic resin, an important deterrent to a leaf-eating caterpillar, Euphydryas chalcedona. The resin can also retard water loss during drought. Furthermore, the leaf resin content differs among plants and populations.

Sagebrush carbon allocation patterns and grasshopper nutrition: the influence of CO enrichment and soil mineral limitation.

Artemisia tridentata seedlings were grown under carbon dioxide concentrations of 350 and 650 μl l and two levels of soil nutrition. In the high nutrient treatment, increasing CO led to a doubling of shoot mass, whereas nutrient limitation completely constrained the response to elevated CO. Root biomass was unaffected by any treatment.

Growth pattern and carbon allocation to volatile leaf terpenes under nitrogen-limiting conditions in Heterotheca subaxillaris (Asteraceae).

Rosettes of Heterotheca subaxillaris were grown at four levels of nitrate. Individual leaf volatile mono- and sesquiterpene content, leaf nitrogen content, and root and shoot dry weight were measured on individual leaves every two weeks for 18 weeks. Rosettes with the highest nitrate availability had 2.

Herbivory on Diplacus aurantiacus shrubs in sun and shade.

This study tested the hypothesis that carbon allocation to the production of leaf antiherbivore chemicals reflects the intensity of herbivory and interacts with resource allocation to photosynthesis. The amount of herbivory by Euphydryas chalcedona butterfly larvae was measured on Diplacus aurantiacus shrubs growing in different daily solar irradiance regimes. The amount of herbivory sustained by plants was directly related to the degree of solar irradiance the shrubs received and to characteristics which vary with light intensity, e.