Systemic enrichment of antifungal traits in the rhizosphere microbiome after pathogen attack

1. Plant-associated microbial communities are crucial for plant growth and play an important role in disease suppression. Community composition and function change upon pathogen attack, yet to date, we do not know whether these changes are a side effect of the infection or actively driven by the plant. 2. Here, we used a split-root approach to test whether barley plants recruit bacteria carrying antifungal traits upon infestation with Fusarium graminearum. Split-root systems allow disentangling local infection effects, such as root damage, from systemic, plant-driven effects on microbiome functionality. We assessed the recruitment of fluorescent pseudomonads, a taxon correlated with disease suppression, and of two well-described antifungal genes (phlD coding for 2,4-DAPG and hcnAB coding for HCN). 3. We show an enrichment of fluorescent pseudomonads, phlD and hcnAB, upon pathogen infection. This effect was only measurable in the uninfected root compartment. We link these effects to an increased chemotaxis of pseudomonads towards exudates of infected plants. 4. Synthesis. We conclude that barley plants selectively recruited bacteria carrying antifungal traits upon pathogen attack and that the pathogen application locally interfered with this process. By disentangling these two effects, we set the base for enhancing strategies unravelling how pathogens and plant hosts jointly shape microbiome functionality

A global synthesis reveals biodiversity-mediated benefits for crop production

Human land use threatens global biodiversity and compromises multiple ecosystem functions critical to food production. Whether crop yield-related ecosystem services can be maintained by a few dominant species or rely on high richness remains unclear. Using a global database from 89 studies (with 1475 locations), we partition the relative importance of species richness, abundance, and dominance for pollination; biological pest control; and final yields in the context of ongoing land-use change. Pollinator and enemy richness directly supported ecosystem services in addition to and independent of abundance and dominance. Up to 50% of the negative effects of landscape simplification on ecosystem services was due to richness losses of service-providing organisms, with negative consequences for crop yields. Maintaining the biodiversity of ecosystem service providers is therefore vital to sustain the flow of key agroecosystem benefits to society. [Abstract copyright: Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).

Bumble bees show an induced preference for flowers when primed with caffeinated nectar and a target floral odor

Caffeine is a widely occurring plant defense chemical that occurs in the nectar of some plants, e.g., Coffea or Citrus spp., where it may influence pollinator behavior to enhance pollination. Honey bees fed caffeine form longer lasting olfactory memory associations, which could give plants with caffeinated nectar an adaptive advantage by inducing more visits to flowers. Caffeinated free-flying bees show enhanced learning performance and are more likely to revisit a caffeinated target feeder or artificial flower, although it is not clear whether improved memory of the target cues or the perception of caffeine as a reward is the cause. Here, we show that inexperienced bumble bees (Bombus terrestris) locate new food sources emitting a learned floral odor more consistently if they have been fed caffeine. In laboratory arena tests, we fed bees a caffeinated food alongside a floral odor blend (priming) and then used robotic experimental flowers to disentangle the effects of caffeine improving memory for learned food-associated cues versus caffeine as a reward. Inexperienced bees primed with caffeine made more initial visits to target robotic flowers emitting the target odor compared to control bees or those primed with odor alone. Caffeine-primed bees tended to improve their floral handling time faster. Although the effects of caffeine were short lived, we show that food-locating behaviors in free-flying bumble bees can be enhanced by caffeine provided in the nest. Consequently, there is potential to redesign commercial colonies to enhance bees’ forage focus or even bias bees to forage on a specific crop

Wertschöpfungsorganisation und Differenzierungsdilemma in der Automobilindustrie

Wie viele andere Branchen befindet sich auch die Automobilbranche in einem voranschreitenden Modularisierungsprozess. Das betrifft sowohl die Produktion als auch die Distribution. Standardisierung und Modularisierung der Wertschöpfungsaktivitäten und -prozesse führen jedoch zu einem betriebswirtschaftlichen Zielkonflikt: die Erzielung von Effizienzvorteilen einerseits und Differenzierungsmöglichkeiten andererseits. Im vorliegenden Beitrag wird am Beispiel der Automobilindustrie dargestellt, wie Unternehmen dem Differenzierungsdilemma entgehen können. Dazu werden markenspezifische Wertschöpfungsorganisationen im Rahmen von Integrationsmessungen systematisiert und verglichen. Anhand der Merkmale unterschiedlicher Organisationsformate wird der Zusammenhang zwischen Wertschöpfungsorganisation und Differenzierungspotential diskutiert. Es zeigt sich, dass diejenigen Hersteller, die sowohl in der Produktion als auch in der Distribution eine hohe Wertschöpfungskontrolle und eine hohe Bindungsintensität der strategisch bedeutenden Lieferanten beziehungsweise Händler aufweisen, Wettbewerbsvorteile gegenüber ihren Konkurrenten erzielen und ein strategisch relevantes Differenzierungspotential erreichen