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Abstract Detail

Phytochemistry: From atoms to organisms

Howard, Mia [1].

Successional shifts in microbial communities affect plant-herbivore interactions in nature and agriculture.

Communities of soil microorganisms can respond rapidly to disturbances and affect the expression of ecologically important plant traits, including resistance to insect herbivores. We have found that soil microbiomes shift drastically over the course of fallow/oldfield succession, altering the community that assembles in the rhizosphere of a dominant native plant, goldenrod, Solidago altissima (Asteraceae). These successional microbial shifts can be functional, as inoculating S. altissima plants with late succession (15 years fallow) microbial communities conferred greater resistance to one of their most abundant and damaging insect herbivores, Trirhabda sp. (Chrysomelidae), than their counterparts grown in early succession (2 years fallow) microbiomes. This microbially-mediated successional trend in herbivore resistance parallels patterns of resistance observed in the field, suggesting that shifts in soil microbial communities over succession play an important role in driving changes in plant resistance phenotypes and patterns of herbivory. While our results indicate that these microbial shifts can play an important role in goldenrod ecology, they might similarly affect the ecology of other plants, including crops--and could have applications in agriculture. Thus, we investigated the effects of soil microbiomes from agricultural fields and different stages of succession (1, 3, and 16 years fallow), collected from a large-scale field experiment, on the growth and pest resistance of four crops: maize, tomato, cucumber, and lettuce. We found that microbiomes from fallow agricultural fields altered the growth and pest resistance of plants, but the effects were species-specific. Consistent with the pattern we observed in S. altissima, plants were generally more resistant to the generalist pest Trichoplusia ni when inoculated with the later succession microbiomes, particularly in contrast to those treated with agricultural microbiomes. However, for tomato plants, the opposite pattern was observed with regard to Spodoptera frugiperda resistance. Collectively, these results indicate that plant responses to microbiomes are species-specific and emphasize the need characterize the responses of taxonomically and functionally diverse plant species to different microbiomes. Yet, we found that microbiomes from fallow fields have the potential to affect agronomically important crop traits and as farmers incorporate fallow land into their landscape for other ecosystem services (e.g., habitat for pollinators and natural enemies of pests), assessing the soils of these communities as sources of functional microbiomes may reveal additional benefits.

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Related Links:
Howard et al 2020 (goldenrod)
Howard et al 2020 (crops)

1 - Indiana University, Bloomington, IN, 47405, United States

aboveground-belowground interactions
plant-soil feedbacks
plant defense
fallow succession
Chemical ecology
plant-insect interactions
herbicide resistance.

Presentation Type: Colloquium Presentations
Session: C05, Phytochemistry: From Atoms to Organisms
Location: /
Date: Wednesday, July 21st, 2021
Time: 11:15 AM(EDT)
Number: C05005
Abstract ID:1115
Candidate for Awards:None

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