Biology subjects

Craig, M. E.

Publications and source records attributed to Craig, M. E..

4 recordsLinked to original sources

bioRxiv2025

Which plant traits increase soil carbon sequestration? Empirical evidence from a long-term poplar genetic diversity trial

Breeding or engineering crops to increase soil organic carbon (SOC) storage is a potential route to land-based carbon dioxide removal on working agricultural lands. However, due to limited observational datasets plus shifting paradigms of SOC stabilization, there is a lack of understanding of which plant traits to target for SOC enhancement or the ultimate sequestration potential of such measures. Existing long-term common gardens of genetically diverse plant populations may provide an opportunity to evaluate biological controls on SOC outcomes, separate from environmental or management variability. Here we report on soil carbon and root chemical data collected for 24 genotypes within a 13-year-old common garden in northwestern Oregon planted with over a thousand natural variants of Populus trichocarpa. Fractionating surface soil (0-15 cm) revealed substantial variation in stocks of mineral-associated organic matter (MAOM; 18-67 tonnes C/ha) and particulate organic matter (POM; 2-22 tonnes C/ha). Tree genotype explained 24 and 26% of the MAOM and POM stock variability, respectively, after controlling for background variability. We found minimal association between SOC concentration and either aboveground tree productivity or conventional metrics of root biomass recalcitrance (C/N ratios and lignin content). However, root elemental content appeared influential for MAOM-C, which showed a strong positive association with root aluminum (Al), and strong negative association with root boron (B) and magnesium (Mg). Furthermore, root concentrations of these elements were highly heritable (57-78%) and not simply a reflection of background variation in bulk soil elemental concentrations. We estimate that surface SOC stocks under these 24 genotypes have diverged at rates of up to 1.2-4.3 tonnes C/ha/yr. These results suggest that genetic diversity trials have value for elucidating biological controls on SOC dynamics, and that traits associated with root elemental content may be an important target for enhancing SOC.

ecology↗

bioRxiv2023

Intraspecies variability in plant and soil chemical properties in a common garden plantation of the energy crop Populus

Optimizing crops for synergistic soil carbon (C) sequestration represents a frontier approach toward CO2 removal in food and bioenergy production systems. While the central roles of plants in biological C capture and storage belowground in soils is well known, we lack an understanding of how intraspecies variation in bioenergy plants affects soil biogeochemistry. This knowledge gap is exacerbated by spatial heterogeneity in soil and plant systems, and by the difficulty of characterizing belowground plant traits. Here, we sought to obtain first insights on the spatial variation of C and nutrients in soil and plant tissues from a common garden field site of diverse, natural variant, Populus trichocarpa genotypes--grown and characterized previously for aboveground biomass-to-biofuels research. Such field sites represent a potential resource for evaluating genotype-specific effects on soil C, but this usage may be complicated due to dense plantings of intermixed genotypes. Thus, we sampled soils at the scale of individual trees to determine whether it is feasible to detect soil property variation with different plant genotypes in this system. We additionally sampled stem and root tissues to evaluate the potential for inferring important belowground traits based on aboveground-belowground correlations. We found that substantial variation in soil properties could be explained at the scale of individual trees, suggesting that genetically diverse plantations can be used to assess plant-soil correlations. Though we did not observe genotype-specific patterns in soil C, other properties such as soil acid-base chemistry (soil pH and base cations) and bulk density showed genotype-specific correlations. Stem and root nutrient levels were generally not correlated, suggesting that belowground traits should be measured directly. In conclusion, our pilot study suggests that long-term common gardens of genome-wide association study populations represent useful resources for understanding plant genotypic relationships with soil properties in Populus field study test plots. These resources could be used to develop verified plant species, geographic region-specific standardized sampling methods, and baseline data. Such context-specific, empirically verified data and models will be necessary for informing applied research strategies in selecting high aboveground productivity genotypes for enhanced soil C storage in managed, commercial scale, woody bioenergy crop plantation systems.

plant biology↗

bioRxiv2022

Environmental and genetic disease modifiers of haploinsuffciency of A20

Monogenic diseases can often manifest diverse clinical phenotypes and cause diagnostic dilemmas. While monoallelic loss-of-function variants in TNFAIP3 (Haploinsufficiency of A20; HA20) cause a highly penetrant autoinflammatory disease, the variable expressivity suggest a role for additional genetic and environmental disease modifiers. Here, we identify critically ill children who inherited a family-specific TNFAIP3 deletion from one of their otherwise healthy parents. Each of the probands also inherited in trans a subtle loss-of-function I207L TNFAIP3 variant that is common in Oceania, originally introgressed from Denisovans. Modelling this compound heterozgous state in mice under specific pathogen free conditions demonstrated a reduced threshold to break immune tolerance. Exaggerated immune responses were precipitated by inheriting the two genetic hits on the TNFAIP3 checkpoint coupled with increasing the microbial challenge to immune tolerance, either by co-housing with pet store mice carrying a wild microbial burden or by transient dietary exposure to a chemical that diminishes the intestinal mucin barrier separating gut microbes from immune sensing systems. These data illuminate second-hit genetic and environmental modifiers contributing to complex inflammatory and autoimmune disease. Increased mechanistic understanding of the presence and contribution of disease modifiers will aid diagnostic and prognostic patient stratification and potentially reveal novel therapeutic opportunities.

immunology↗

bioRxiv2019

Phospho-tuning immunity through Denisovan, modern human, and mouse TNFAIP3 gene variants

Resisting or tolerating microbes are alternative strategies to survive infection, but little is known about the evolutionary mechanisms controlling this balance. Here, genomic analyses of anatomically modern humans, extinct Denisovan hominins, and mice revealed a series of missense variants in the immune response inhibitor A20 (encoded by TNFAIP3), substituting non-catalytic residues of the ubiquitin protease domain to diminish I{kappa}B-dependent phosphorylation and activation of A20. Two A20 variants with partial phosphorylation deficits appeared beneficial: one originating in Denisovans and introgressed in modern humans throughout Oceania, and another in a mouse strain resistant to Coxsackievirus. By contrast, a variant with 95% loss of phosphorylation caused spontaneous inflammatory disease in humans and mice. Analysis of the partial phosphorylation variant in mice revealed diminished tolerance of bacterial lipopolysaccharide or to poxvirus inoculation as trade-offs for enhanced immunity.\n\nOne Sentence SummaryModern and ancient variants reveal a genetically tunable element for balancing immunity and microbial tolerance.

immunology↗