Biology subjects

Arce, C. C. M.

Publications and source records attributed to Arce, C. C. M..

4 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↗

bioRxiv2021

Adaptations and responses of the common dandelion to low atmospheric pressure in high altitude environments

Atmospheric pressure is an important, yet understudied factor that may shape plant ecology and evolution. By growing plants under controlled conditions at different experimental stations in the Swiss alps, we evaluated the impact of ecologically realistic atmospheric pressures between 660 and 950 hPa on the growth and defence of different dandelion populations. Low atmospheric pressure was associated with reduced root growth and defensive sesquiterpene lactone production. Defense suppression only occurred in populations originating from lower altitudes. Populations from higher altitudes constitutively produced less sesquiterpene lactones and did not suffer from suppression under low atmospheric pressure. We conclude that atmospheric pressure modulates root growth and defence traits, and that evolutionary history shapes plant phenotypic responses to atmospheric pressure. Our findings have important implications for our understanding of altitudinal gradients and the future use of plants as a source of food and bioactive metabolites in extraterrestrial habitats.

plant biology↗

bioRxiv2020

Plant-derived CO2 mediates long-distance host location and quality assessment by a root herbivore

Insect herbivores can use volatile and visual cues to locate and select suitable host plants from a distance. The importance of CO2, arguable the most conserved volatile marker of metabolic activity, is not well understood in this context, even though many herbivores are known to respond to minute differences in CO2 concentrations. To address this gap of knowledge, we manipulated CO2 perception of the larvae of the western corn rootworm (Diabrotica virgifera virgifera; WCR) through RNA interference and studied how CO2 perception impacts their interaction with their host plant, maize (Zea mays). We show that the expression of a putative Group 2 carbon dioxide receptor, DvvGr2, is specifically required for dose-dependent larval responses to CO2 in the ppm range. Silencing DvvGr2 has no effect on the ability of WCR larvae to locate host plants at short distance (<9 cm), but impairs host location at greater distances. Using soil arenas and olfactometer experiments in combination with DvvGr2 silencing and CO2 scrubbing, we demonstrate that WCR larvae use CO2 as a long-range host plant finding cue, but employ other volatiles for short-range host location. We furthermore show that the larvae use CO2 as a fitness-relevant long-distance indicator of plant nutritional status: Maize plants that are well-fertilized emit more CO2 from their roots and are better hosts for WCR than plants that are nutrient-deficient, and the capacity of WCR larvae to distinguish between these plants depends exclusively on their capacity to perceive CO2 through DvvGr2. This study unravels how CO2 can mediate plant-herbivore interactions by serving as a distance-dependent host location and quality assessment cue.

ecology↗

bioRxiv2019

Plant defense resistance in natural enemies of a specialist insect herbivore

Plants defend themselves against herbivores through the production of toxic and deterrent metabolites. Adapted herbivores can tolerate and sequester these metabolites, allowing them to feed on defended plants and become toxic to their own enemies. Can herbivore natural enemies overcome sequestered plant defense metabolites to prey on adapted herbivores? To address this question, we studied how entomopathogenic nematodes cope with benzoxazinoid defense metabolites that are produced by grasses and sequestered by a specialist maize herbivore, the western corn rootworm. We find that nematodes from US maize fields in regions in which the western corn rootworm was present over the last 50 years are behaviorally and metabolically resistant to sequestered benzoxazinoids and more infective towards the western corn rootworm than nematodes from other parts of the world. Exposure of a benzoxazinoid-susceptible nematode strain to the western corn rootworm for five generations results in higher behavioral and metabolic resistance and benzoxazinoid-dependent infectivity towards the western corn rootworm. Thus, herbivores that are exposed to a plant defense sequestering herbivore can evolve both behavioral and metabolic resistance to plant defense metabolites, and these traits are associated with higher infectivity towards a defense sequestering herbivore. We conclude that plant defense metabolites that are transferred through adapted herbivores may result in the evolution of resistance in herbivore natural enemies. Our study also identifies plant defense resistance as a novel target for the improvement of biological control agents.

plant biology↗