Biology subjects

Turlings, T. C. J.

Publications and source records attributed to Turlings, T. C. J..

6 recordsLinked to original sources

bioRxiv2026

Photorhabdus metabolites reshape soil microbial communities and promote plant growth and insect resistance

Photorhabdus bacteria are potent insect-killing microbes associated with entomopathogenic nematodes and offer opportunities for environmentally benign pest control. They can be applied as foliar sprays or soil drenches without their nematode vector, resulting in massive amounts of Photorhabdus cells and their (toxic) metabolites introduced into the soil. However, their effects beyond the target organisms are unknown. To fill this knowledge gap, we investigated the soil legacy effects of Photorhabdus cells and their metabolites on soil microbial communities, plant performance and resistance to herbivores. To this end, we first conditioned soils with i) mechanically killed (MK) or Photorhabdus-infected insect larvae, ii) aqueous extracts of MK or Photorhabdus-infected insect larvae, iii) cell-free Photorhabdus supernatants, iv) autoclaved soil complemented with live soil previously conditioned with MK or Photorhabdus-infected insect larvae. We then grew maize plants in these soils and measured plant biomass, profiled soil microbial communities and plant metabolites, and evaluated plant resistance against two pest insects Diabrotica balteata and Spodoptera frugiperda. We found that conditioned soils increased plant biomass by 10-26% relative to controls and significantly altered soil bacterial and nematode communities, and to a lesser extent, fungal communities. Re-inoculating conditioned soil microbiota into autoclaved soils recreated the plant growth-promoting effects, indicating microbial-mediated mechanisms. Additionally, plants grown in soils conditioned with Photorhabdus-infected insect cadavers were often more resistant to herbivorous insect attack, in a strain-specific manner. On average, D. balteata and S. frugiperda larvae gained 10-20% and 10-59% less weight, respectively, when fed on plants grown in conditioned soils than on plants grown in control soils. The plant metabolic profiles of plant leaves and roots also varied with resistance levels. We conclude that Photorhabdus metabolites modulate soil microbial communities towards a structure that enhances plant growth and triggers systemic responses against herbivores.

microbiology↗

bioRxiv2025

A plant immune receptor mediates tritrophic interactions by linking caterpillar detection to predator recruitment

Plants deploy direct and indirect defenses in response to insect herbivory. The specific antiherbivore responses involve cell surface immune receptors that recognize herbivore associated molecular patterns (HAMPs), yet the ecological relevance of this molecular interplay remains unexplored. We demonstrate that the Inceptin Receptor (INR) encoded by common bean, upon recognition of inceptin, a HAMP in caterpillar oral secretions, orchestrates a tritrophic interaction. Laboratory and field experimentation in Mexico using a naturally occurring inceptin-insensitive mutant and its near-isogenic wild type equivalent, revealed that inceptin recognition by INR activates an herbivore-specific immune pathway, and triggers the emission of a volatile blend that recruits predatory wasps. These findings provide a novel molecular-to-ecological link, revealing how an immune receptor mediates ecologically relevant plant-insect-predator interactions in nature.

plant biology↗

bioRxiv2025

From leaves to defenders: how amount and dispersion of leaf damage affect extrafloral nectar production and ant-mediated protection in wild cotton (Gossypium hirsutum)

O_LIExtrafloral nectar (EFN) drives mutualistic interactions between plants and ants. However, EFN production is costly, and its induction is predicted to vary with herbivore-related factors. We examine how the amount and within-plant damage spatial uniformity (i.e., dispersed and concentrated damage) affect EFN production and ant-mediated defence in wild cotton (Gossypium hirsutum). Previous work suggests that severe and concentrated damage is costliest to plants, leading us to hypothesise that such damage would induce greater EFN production and, consequently, stronger ant attraction and protection. C_LIO_LIWe conducted a greenhouse experiment in which plants were subjected to one of the following mechanical damage treatments: control (no damage), low damage (two damaged leaves, 30% of area removed each), high concentrated damage (two damaged leaves, 60% each), and high dispersed damage (four damaged leaves, 30% each; i.e., same total area than concentrated damage). The day after treatments, we measured EFN volume and sugar content from one nectary per plant (a per-nectary EFN response), and the number of secreting nectaries per plant (a proxy for whole-plant level EFN response). Subsequently, we performed a field experiment using the same treatments to evaluate EFN-mediated ant recruitment and ant-provided protection by placing caterpillars on plants. C_LIO_LIBoth high-damage treatments increased EFN volume per nectary, whereas low damage did not. However, against our prediction, dispersed damage was the only treatment that increased the number of secreting nectaries. Consistently, once placed in the field, plants with dispersed damage recruited more ants and caterpillars on them were more likely to be attacked by ants. C_LIO_LIContrary to expectations, plants subjected to dispersed damage exhibited a greater total investment in EFN, presumably via local induction of more nectaries per plant, and thereby enhancing ant-mediated defence. This study highlights the importance of herbivory intensity and within-plant spatial uniformity in shaping ant-plant interactions. C_LI

ecology↗

bioRxiv2022

The N-terminal subunit of vitellogenin in planthopper eggs and saliva acts as a reliable elicitor that induces defenses in rice

Vitellogenins are essential for the development and fecundity of insects, but these proteins may also betray them, as we show here. We found that the small N-terminal subunit of vitellogenins of the planthopper Nilaparvata lugens (NlVgN) triggers strong defense responses in rice plants when it enters the plant during feeding or oviposition by the insect. The defenses induced by NlVgN in plants not only decreased the hatching rate of N. lugens eggs, but also induced volatile emissions in rice plants, which rendered them attractive to a common egg parasitoid. VgN of other planthoppers were found to trigger the same defense responses in rice. We further show that VgN deposited during planthopper feeding compared to during oviposition induces a somewhat different response, probably targeting the appropriate developmental stage of the insect. The key importance of VgN for planthopper performance precludes possible evolutionary adaptions to prevent detection by rice plants.

ecology↗

bioRxiv2022

Laboratory and field trials reveal the potential of a gel formulation of entomopathogenic nematodes as biocontrol against the fall armyworm (Spodoptera frugiperda)

1.The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) can cause tremendous yield losses in maize. Its invasion into Africa and Asia has led to an enormous influx of insecticides into maize agro-ecosystems. Safe, effective and readily available alternatives are desperately needed. Entomopathogenic nematodes (EPN) are commonly used against soil insect pests, but can also control some above-ground pests. We explored the possibility to control FAW by incorporating EPN into a formulation that can be easily applied into the whorl of maize plants, where the caterpillars mostly feed. We tested this approach in laboratory cage experiments as well as in field trials. In the laboratory, treating maize plants with a low dose of EPN in a carboxymethyl cellulose (CMC) gel formulation (about 3000 infective juveniles per plant), caused 100% mortality of FAW caterpillars and prevented plant damage considerably, whereas EPN applied in water or a surfactant-polymer-formulation (SPF) caused 72% and 94% mortality, respectively. Under field conditions, one-time treatments with EPN applied in water, SPF or CMC gel were all able to prevent significant plant damage, but only the EPN-gel formulation significantly reduced FAW infestation. Notably, the gel formulation was as effective as a standard dose of cypermethrin, an insecticide commonly used against FAW. Repeated applications may be needed to reduce re-infestations by FAW across a whole cropping season depending on the local maize phenology and pest dynamics. These findings demonstrate that EPN are excellent candidates for the biological control of FAW and are a safe and sustainable alternative to chemical insecticides. HighlightsO_LIEntomopathogenic nematodes are highly lethal to fall armyworm caterpillars. C_LIO_LIAppropriate formulation of the nematodes is crucial for above-ground application. C_LIO_LIA gel formulation of entomopathogenic nematodes was as effective as chemical insecticides. C_LIO_LIEntomopathogenic nematodes can be used for the control of fall armyworm in maize. C_LI

ecology↗

bioRxiv2021

Cooperative herbivory between two important pests of rice

Normally, when different species of herbivorous arthropods feed on the same plant this leads to fitness reducing competition. We found this to be uniquely different for two of Asias most destructive rice pests, the brown planthopper and the rice striped stem borer. Both insects directly and indirectly benefit from jointly attacking the same host plant. Double infestation improved plant quality, particularly for the stemborer because the planthopper fully suppresses caterpillar-induced production of proteinase inhibitors. It also drastically reduced the risk of egg parasitism, due to diminished parasitoid attraction. Females of both pests have adapted their oviposition behaviour accordingly. Their strong preference for plants infested by the other species even overrides their avoidance of plants already attacked by conspecifics. This uncovered cooperation between herbivores is telling of the exceptional adaptations resulting from the evolution of plant-insect interactions, and points out mechanistic vulnerabilities that can be targeted to control two major pests.

ecology↗