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Microbial communities and soil physiochemical properties as mediators of heterosis expression in maize
Clouse, Kayla
Clouse, Kayla
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Abstract
Hybrids account for nearly all commercially planted grain since crosses between inbred lines produce F1 offspring that greatly outperform their parents – a phenomenon known as heterosis. While the genetic and molecular mechanisms underlying heterosis are still hotly contested, emerging research has demonstrated the importance of soil microbes in heterosis expression. Previous work shows that perturbation of the soil microbiome intensified heterosis in one field site but reduced it in another, suggesting that the underlying mechanism may depend on the soil community composition, the abiotic environment, or both. In chapter 1, I explore whether heterosis expression is dependent on microbial adaptation to local environmental conditions. My results suggest that microbial adaptation plays a marginal role in heterosis expression but that the abiotic environment alone is likely a larger driver. In chapter 2, I explore whether hybrids have superior resistance to weak soil pathogens and if higher availability of soil nutrients diminishes or diverts plant-microbe interactions. I found that despite minimal differences in soil pathogen abundance, the nutrient amendment affected the root microbiome and heterosis expression in an agricultural soil community but not a prairie community. In chapter 3, I explore whether non-pathogenic soil microbes trigger the host microbe-associated molecular pattern response leading to a reduction in growth in inbred maize. While inbred maize genotypes were generally less responsive to a community of non-pathogenic microbes than hybrid maize, I did not observe differences in plant defense gene expression between inbred and hybrid maize. In chapter 4, I discuss how plant genotypes affect the microbiome and how we can employ plant genetics to manipulate the microbiome for improved sustainability of agricultural systems. Together, these studies provide novel insights into how ecological factors mediate heterosis expression and open new research avenues to explore the mechanisms underlying this widespread and critically important phenomenon.
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Date
2024-01-01
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University of Kansas
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This item contains archived web content.
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Clouse_ku_0099D_19891.pdf
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- Embargoed until 2174-05-31
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Keywords
Plant sciences, Microbiology, Ecology, genotype by environment interactions, heterosis, maize, plant microbiome, plant-microbe interactions, soil ecology