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Abstract Background and AimsNitrogenous fertilizers provide a short-lived benefit to crops in agroecosystems, but stimulate nitrification and denitrification, processes that result in nitrate pollution, N2O production, and reduced soil fertility. Recent advances in plant microbiome science suggest that genetic variation in plants can modulate the composition and activity of rhizosphere N-cycling microorganisms. Here we attempted to determine whether genetic variation exists inZea maysfor the ability to influence the rhizosphere nitrifier and denitrifier microbiome under “real-world” conventional agricultural conditions. MethodsTo capture an extensive amount of genetic diversity within maize we grew and sampled the rhizosphere microbiome of a diversity panel of germplasm that included ex-PVP inbreds (Z. maysssp.mays), ex-PVP hybrids (Z. maysssp.mays), and teosinte (Z. maysssp. mexicanaandZ. maysssp.parviglumis). From these samples, we characterized the microbiome, a suite of microbial genes involved in nitrification and denitrification and carried out N-cycling potential assays. ResultsHere we are showing that populations/genotypes of a single species can vary in their ecological interaction with denitrifers and nitrifers. Some hybrid and teosinte genotypes supported microbial communities with lower potential nitrification and potential denitrification activity in the rhizosphere, while inbred genotypes stimulated/did not inhibit these N-cycling activities. These potential differences translated to functional differences in N2O fluxes, with teosinte plots producing less GHG than maize plots. ConclusionTaken together, these results suggest thatZeagenetic variation can lead to changes in N-cycling processes that result in N leaching and N2O production, and thereby are selectable targets for crop improvement. Understanding the underlying genetic variation contributing to belowground microbiome N-cycling into our conventional agricultural system could be useful for sustainability.
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Heterosis of leaf and rhizosphere microbiomes in field‐grown maize
Summary Macroorganisms’ genotypes shape their phenotypes, which in turn shape the habitat available to potential microbial symbionts. This influence of host genotype on microbiome composition has been demonstrated in many systems; however, most previous studies have either compared unrelated genotypes or delved into molecular mechanisms. As a result, it is currently unclear whether the heritability of host‐associated microbiomes follows similar patterns to the heritability of other complex traits.We take a new approach to this question by comparing the microbiomes of diverse maize inbred lines and their F1hybrid offspring, which we quantified in both rhizosphere and leaves of field‐grown plants using 16S‐v4 and ITS1 amplicon sequencing.We show that inbred lines and hybrids differ consistently in the composition of bacterial and fungal rhizosphere communities, as well as leaf‐associated fungal communities. A wide range of microbiome features display heterosis within individual crosses, consistent with patterns for nonmicrobial maize phenotypes. For leaf microbiomes, these results were supported by the observation that broad‐sense heritability in hybrids was substantially higher than narrow‐sense heritability.Our results support our hypothesis that at least some heterotic host traits affect microbiome composition in maize.
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- Award ID(s):
- 1656006
- PAR ID:
- 10368445
- Publisher / Repository:
- Wiley-Blackwell
- Date Published:
- Journal Name:
- New Phytologist
- Volume:
- 228
- Issue:
- 3
- ISSN:
- 0028-646X
- Page Range / eLocation ID:
- p. 1055-1069
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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