Biology subjects

Cahoon, E.

Publications and source records attributed to Cahoon, E..

4 recordsLinked to original sources

bioRxiv2026

Drought Dominates Engineered Lipid Sink Effects on Sorghum Physiology and Carbon Allocation

Determining the environmental limits that govern how engineered metabolic traits control whole-plant carbon (C) allocation is essential for developing climate-resilient bioenergy systems. Oil-enhanced sorghum offers a promising strategy to boost aboveground energy density, yet its system-wide effects on root C investment and soil C delivery, particularly under drought, are largely uncharacterized. Here, we provide the first comprehensive assessment of these interactions using whole-plant 13CO2 continuous labeling, depth-specific sampling of roots and rhizosphere soil, and coordinated measurements of photosynthesis, stomatal anatomy, tissue nitrogen, and root non-structural carbohydrates (NSCs). Under well-watered conditions, oil enhancement produced distinct aboveground physiological changes, including slightly longer stomata, lower stomatal density, significantly higher leaf nitrogen concentration and biomass, and greater leaf 13C enrichment. Importantly, these aboveground changes did not translate into detectable shifts in the allocation of recent photosynthate to belowground pools. In contrast, drought acted as a dominant regulatory factor, reorganizing C flow across both genotypes by suppressing photosynthesis and leaf water status, increasing root nitrogen and NSC reserves, and significantly promoting the retention of recent assimilates in shallow root systems. Depth-specific 13C patterns showed that drought reduced new C incorporation into deep roots while increasing 13C enrichment in deep rhizosphere soil, suggesting that drought altered the balance between C investment in root growth and rhizodeposit C inputs at depth. Ultimately, soil moisture availability was an overriding determinant of belowground C partitioning and vertical C delivery, superseding the influence of the engineered lipid sink. These findings provide new mechanistic insight into the environmental constraints on C flow in an engineered bioenergy crop and identify moisture-driven limitations as the primary bottleneck for translating synthetic metabolic innovations into robust, ecosystem-level C outcomes.

ecology↗

bioRxiv2020

Palmitvaccenic acid (Δ11-cis-hexadecenoic acid) is synthesized by an OLE1-like desaturase in the arbuscular mycorrhiza fungus Rhizophagus irregularis

Arbuscular mycorrhiza (AM) fungi deliver mineral nutrients to the plant host in exchange for reduced carbon in the form of sugars and lipids. Colonization with AM fungi upregulates a specific host lipid synthesis pathway resulting in the production of fatty acids. The fungus Rhizophagus irregularis accumulates predominantly palmitic acid (16:0) and the unusual palmitvaccenic acid (16:1{Delta}11cis). Here, we present the isolation and characterization of RiOLE1-LIKE, the desaturase involved in palmitvaccenic acid synthesis, by heterologous expression in yeast and plants. Results are in line with the scenario that RiOLE1-LIKE encodes an acyl-CoA desaturase with substrate specificity for C15-C18 acyl groups, in particular C16. Phylogenetic analysis of RiOLE1-LIKE related sequences revealed that this gene is conserved in AM fungi from the Glomales and Diversisporales, but is absent from non-symbiotic Mortierellaceae and Mucoromycotina fungi, suggesting that 16:1{Delta}11cis provides a specific function during AM colonization.

plant biology↗

bioRxiv2019

Progress toward the identification and stacking of crucial domestication traits in pennycress

The oilseed species Thlaspi arvense (pennycress) is being domesticated as a new crop that can provide both important ecosystem services and intensify farmland output. Through the use of high throughput sequencing and phenotyping, along with classical mutagenesis key traits needed for pennycress domestication have been identified. Domestication traits identified herein include reduced pod shatter, early maturity, reduced seed glucosinolate levels, and improved oil fatty acid content. By taking advantage of pennycress close genetic relationship with Arabidopsis thaliana, the causative mutations responsible for each of these traits have been identified. These mutations have been used to develop molecular markers to begin to stack the traits into individual lines.

plant biology↗

bioRxiv2019

Mapping of transgenic alleles in plants using a Nanopore-based sequencing strategy

Transgenic technology was developed to introduce transgenes into various organisms to validate gene function and add genetic variation for the development of beneficial input or output trait over 40 years ago. However, the identification of the transgene insertion position in the genome, while doable, can be cumbersome in the organisms with complex genomes. Here, we report a Nanopore-based sequencing method to rapidly map transgenic alleles in the soybean genome. This strategy is high-throughput, convenient, reliable, and cost-efficient. The transgenic allele mapping protocol outlined herein can be easily translated to other higher eukaryotes with complex genomes.

plant biology↗