Crystal structure and ligand binding of a sigma-class glutathione S-transferase associated with cross-resistance in a specialist herbivore.

Understanding the molecular mechanisms underlying insect adaptation is critical for elucidating the evolution of pesticide resistance and improving pest management strategies. While host plant preadaptation has been proposed to facilitate insecticide resistance, direct evidence remains limited. Here, we investigated a sigma-class glutathione S-transferase (GST), LdGSTs2, in the Colorado potato beetle (Leptinotarsa decemlineata), a major agricultural pest.

The carboxylesterase AtCXE12 converts volatile (Z)-3-hexenyl acetate to (Z)-3-hexenol in Arabidopsis leaves.

The green leaf volatiles (GLVs) (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate play important roles in plant defense, deterring insect herbivores and attracting their natural enemies, while also serving as airborne signaling molecules capable of enhancing defenses in undamaged plant tissues. Almost all plants produce GLVs after wounding, beginning with the formation of (Z)-3-hexenal, which is subsequently converted to (Z)-3-hexenol and (Z)-3-hexenyl acetate. (Z)-3-hexenyl acetate can then be taken up by nearby plant tissues where it is predicted to be hydrolyzed to (Z)-3-hexenol, a process that is likely to be important in regulating the specific activities of these compounds.

Environmental and Biological Drivers of Root Exudation.

Root exudation is the process by which plants release organic and inorganic metabolites from their roots into the surrounding soil. Root exudation is a dynamic process and shapes plant-environment interactions at the root-soil interface. Little is known about the biological and environmental factors that shape the exuded metabolome, hereafter referred to as the exudome, despite its importance in structuring soil processes.

Leaf Size Determines Damage- and Herbivore-Induced Volatile Emissions in Maize.

Stress-induced plant volatiles play an important role in mediating ecological interactions between plants and their environment. The timing and location of the inflicted damage is known to influence the quality and quantity of induced volatile emissions. However, how leaf characteristics and herbivore feeding behaviour interact to shape volatile emissions is not well understood.

High-resolution kinetics of herbivore-induced plant volatile transfer reveal clocked response patterns in neighboring plants.

Volatiles emitted by herbivore-attacked plants (senders) can enhance defenses in neighboring plants (receivers), however, the temporal dynamics of this phenomenon remain poorly studied. Using a custom-built, high-throughput proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS) system, we explored temporal patterns of volatile transfer and responses between herbivore-attacked and undamaged maize plants. We found that continuous exposure to natural blends of herbivore-induced volatiles results in clocked temporal response patterns in neighboring plants, characterized by an induced terpene burst at the onset of the second day of exposure.

Immature leaves are the dominant volatile-sensing organs of maize.

Plants perceive herbivory-induced volatiles and respond to them by upregulating their defenses. To date, the organs responsible for volatile perception remain poorly described. Here, we show that responsiveness to the herbivory-induced green leaf volatile (Z)-3-hexenyl acetate (HAC) in terms of volatile emission, transcriptional regulation, and jasmonate defense hormone activation is largely constrained to younger maize leaves.

Herbivorous Caterpillars and the Green Leaf Volatile (GLV) Quandary.

Several herbivorous caterpillars contain effectors in their oral secretions that alter the emission of green leaf volatiles (GLVs) produced by the plants upon which the caterpillars are feeding. These effectors include an isomerase, a fatty acid dehydratase (FHD), and a heat-stable hexenal trapping (HALT) molecule. GLVs serve as signaling compounds in plant-insect interactions and inter-and intra-plant communication.

From Acetoin to ( Z)-3-Hexen-1-ol: The Diversity of Volatile Organic Compounds that Induce Plant Responses.

Evidence that plants can respond to volatile organic compounds (VOCs) was first presented 35 years ago. Since then, over 40 VOCs have been found to induce plant responses. These include VOCs that are produced not only by plants but also by microbes and insects.

Green leaf volatiles protect maize (Zea mays) seedlings against damage from cold stress.

Although considerable evidence has accumulated on the defensive activity of plant volatile organic compounds against pathogens and insect herbivores, less is known about the significance of volatile organic compounds emitted by plants under abiotic stress. Here, we report that green leaf volatiles (GLVs), which were previously shown to prime plant defences against insect herbivore attack, also protect plants against cold stress (4 °C). We show that the expression levels of several cold stress-related genes are significantly up-regulated in maize (Zea mays) seedlings treated with physiological concentrations of the GLV, (Z)-3-hexen-1-yl acetate (Z-3-HAC), and that seedlings primed with Z-3-HAC exhibit increased growth and reduced damage after cold stress relative to unprimed seedlings.

Defense priming by non-jasmonate producing fatty acids in maize (Zea mays).

Previously, we described a priming effect of α-linolenic acid (LnA) on anti-herbivore defense response in maize seedlings. We showed that exogenous application of LnA stimulated higher jasmonic acid (JA) accumulation and herbivore-induced plant volatile (HIPV) emission after treatment with insect elicitor (IE). To further investigate the specificity of LnA's priming effect, we incubated maize seedlings in palmitoleic acid (PeicA), γ-linolenic acid (γ LnA) and stearic acid (StA) solutions, and analyzed HIPV emission in response to IE.