Cowpea plants create underground defense system for the next generation after insect attacks
Plants might seem helpless when it comes to insect attacks, but they are known to employ various techniques to deter pests. One of these techniques involves sending out signals to recruit parasitoid wasps, and a new study, published in Cell Reports, has found that at least one plant can extend this deterrent system to future generations growing in the same soil.
Cowpea plants, often targeted by leafminers, have evolved an underground defense mechanism that extends its protective influence to future generations growing in the same soil. This discovery, detailed in a Cell Reports study, reveals that leaf damage activates a plant defense hormone called jasmonate, prompting roots to release beneficial compounds.
These compounds, daidzein and genistein, reshape the soil microbiome, enriching beneficial Bradyrhizobium bacteria. The enriched microbes then re-activate jasmonate signaling, increasing the release of an odor that attracts parasitoid wasps, which prey on leafminers. Remarkably, uninfested cowpeas grown in the soil conditioned by attacked plants attracted more parasitoid wasps and grew larger than those grown in sterilized soil.
This soil-based defense effectively decouples enemy recruitment from immediate herbivore presence, extending the defensive influence of herbivory beyond the attacked plant and generation. While the study focused on cowpea and leafminer interactions, further research is needed to determine if other plants possess similar microbial defense systems and how long this microbial defense will last.
If confirmed, harnessing this plant-soil feedback could help farmers reduce reliance on insecticides, fostering more resilient and sustainable agroecosystems.
Written by urgent.news from Phys.org's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
