Biology subjects

Sanchez-Mahecha, O.

Publications and source records attributed to Sanchez-Mahecha, O..

3 recordsLinked to original sources

bioRxiv2024

Rhizobacteria inoculation of plants for reducing insect pests: A meta-analysis on insect behaviour and fitness

Microbial communities in the plant rhizosphere--the soil region closely associated with plant roots-- play critical roles in shaping plant growth, defence, fitness, and ecosystem processes. Inoculation of plants with specific rhizobacteria strains has shown promising potential for increasing crop yields. Rhizobacteria can also induce plant defences, resulting in reduced insect growth and reproduction, and can manipulate plant biochemistry to alter insect host-choice and recruit natural enemies of the insects. We present a meta-analysis examining the impact of rhizobacteria inoculation of plants on insect fitness and behaviour. Our findings indicate that rhizobacteria inoculation generally reduces herbivore fitness and host choice behaviours. However, effect sizes varied significantly depending on type of herbivore (chewing versus sucking), plant host, and rhizobacterial species. Bacillus spp. showed stronger effects than the commonly studied Pseudomonas spp. Rhizobacteria notably reduced traits such as host choice, leaf consumption, survival, and reproduction of chewing herbivores, while primarily impacting sucking herbivores by reducing reproduction. Single-strain inoculants tended to perform better, especially for sucking herbivores, suggesting potential strain incompatibility issues with multi-strain inoculants. Furthermore, field trials showed less impact on insect fitness reduction compared to experiments under controlled conditions, possibly due to soil diversity and environmental factors affecting inoculant persistence. Despite, very limited experimental data, studies observed that rhizobacteria inoculation of plants can attract parasitoid wasps and predators to the plants. These results underscore the need for considering broader environmental interactions when developing effective rhizobacteria-based pest management strategies. Understanding specific and generalist rhizosphere interactions can aid in developing synthetic microbial communities with broad protective functions across various plants and environments.

ecology↗

bioRxiv2023

Microbe-induced plant resistance against insect pests depends on timing of inoculation, but is consistent across climatic conditions

O_LITo cope with abiotic and biotic stressors, plants have developed mutualistic associations with beneficial soil microbes, but little is known about how (extreme) abiotic conditions impact on microbe-induce resistance to insect herbivores. C_LIO_LIExtreme temperatures are often accompanied by extremes in plant water availability, which together reduce plant growth and change plant physiology. There are potential consequences for increasing plant susceptibility to biotic stresses, and this poses a real challenge for plant productivity. C_LIO_LIWe evaluated how the effects of beneficial soil bacteria (Acidovorax radicis) on barley plant growth and resultant resistance against aphid infestation (Sitobion avenae) were impacted by a single heatwave event across a plant water availability gradient. We also tested if timing of bacterial inoculation (before or after the heatwave) affected bacteria-plant interactions on aphids. C_LIO_LIWe found that heatwaves affected plant biomass allocation from aboveground to belowground tissues. Inoculation with A. radicis led to reduction of aphid numbers, but depended on timing of inoculation, and led to stronger resistance when inoculations occurred closer to aphid infestation. Remarkably, microbe-induced resistance against aphids was consistent across heatwave and water availability treatments. C_LIO_LIThis study provides evidence that beneficial plant-bacteria interactions may represent a potential solution for sustainable agricultural practices to enhance plant growth and response to insect pests under climate change. Future field trials should investigate the consistency of beneficial effects reported here for a better understanding of multispecies interactions in the context of global change. C_LI

ecology↗

bioRxiv2022

Part-night exposure to artificial light at night has more detrimental effects on aphid colonies than fully lit nights

Artificial light at night (ALAN) threatens natural ecosystems globally. While ALAN research is increasing, little is known about how ALAN affects plants and interactions with other organisms. We explored the effects of ALAN on plant defence and plant-insect interactions using barley (Hordeum vulgare) and the English grain aphid (Sitobion avenae). Plants were exposed to full or part nights of 15-20 lux ALAN, or no ALAN control nights, to test the effects of ALAN on plant growth and defence. Although plant growth was only minimally affected by ALAN, aphid colony growth and aphid maturation were reduced significantly by ALAN treatments. Importantly, we found strong differences between full-night and part-night ALAN treatments. Contrary to our expectations, part ALAN had stronger negative effects on aphid colony growth than full ALAN. Defence-associated gene expression was affected in some cases by ALAN, but also positively correlated with aphid colony size, suggesting that the effects of ALAN on plant defences are indirect, and regulated via direct disruption of aphid colonies, rather than via ALAN-induced upregulation of defences. Mitigating ecological side effects of ALAN is a complex problem, as reducing exposure to ALAN increased its negative impact on insect herbivores.

ecology↗