Resuscitation of the microbial seed bank alters plant‐soil interactions

Abstract

While microorganisms are recognized for driving belowground processes that influence the productivity and fitness of plant populations, the vast majority of bacteria and fungi in soil belong to a seed bank consisting of dormant individuals. However, plant performance may be affected by microbial dormancy through its effects on the activity, abundance, and diversity of soil microorganisms. To test how microbial seed banks influence plant‐soil interactions, we purified recombinant resuscitation promoting factor (Rpf), a bacterial protein that terminates dormancy. In a factorially designed experiment, we then applied the Rpf to soil containing field mustard (Brassica rapa), an agronomically important plant species. Plant biomass was ~33% lower in the Rpf treatment compared to plants grown with an unmanipulated microbial seed bank. In addition, Rpf reduced soil respiration, decreased bacterial abundance, and increased fungal abundance. These effects of Rpf on plant performance were accompanied by shifts in bacterial community composition, which may have diluted mutualists or resuscitated pathogens. Our findings suggest that changes in microbial seed banks may influence the magnitude and direction of plant‐soil feedbacks in ways that affect above‐ and belowground biodiversity and function.

The resuscitation-promoting factor (Rpf) from Micrococcus luteus and its putative reaction product 1,6-anhydro-MurNAc increase culturability of environmental bacteria

“…The most potent effect was observed following recombinant Rpf addition on samples AT and soil2. We performed systematic literature searches in different databases and could not find an equivalent experiment; however, two studies examined the effect of adding Rpf to the soil, in contrast to the cultivation media [33,34]. One study showed that 16S rRNA gene copies increased after adding the protein compared to the control [34].…”

“…One study showed that 16S rRNA gene copies increased after adding the protein compared to the control [ 34 ]. Surprisingly the second study found that the number of bacterial 16S rRNA of copies decreased while fungal ITS copies increased [ 33 ].…”

A framework for integrating microbial dispersal modes into soil ecosystem ecology

“…Incorporating dispersal might mean a no-dispersal or enhanced-dispersal treatment as part of the experimental design, or accounting for new taxa from the atmosphere at regional scales or along fungal highways at local scales. Incorporating dormancy might mean including a resuscitation treatment (e.g., bacterial resuscitation factor Rpf, see ( Kuo et al., 2021 )), or filtering taxa based on microbial activity. Although at present our methods for quantifying active versus non-active fractions are imperfect.…”

Microbial trait-based approaches for agroecosystems

“…For example, the disruption of microbial seed banks has recently been shown to alter the structure and function of belowground communities in ways that have implications for the growth and performance of plant populations (Kuo et al, 2021).…”