Browsing by Author "Sparks, Erin E."
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Item Evaluation of Brace Root Parameters and Its Effect on the Stiffness of Maize(in silico Plants, 2022-05-12) Obayes, Shaymaa K.; Timber, Luke; Head, Monique; Sparks, Erin E.Plant mechanical failure (lodging) causes significant yield loss for crops such as maize. Understanding this failure has relied on static measurements of plant biomechanics. In this study, digital image correlation techniques are used to capture dynamic motion to understand the plant mechanical behavior of maize stalks in the presence and absence of brace roots, which are stem-borne aerial roots known to stabilize the maize stalks. The data show that brace roots function to secure the maize stalk, limiting both deflection and uplift. A finite element (FE) model is developed using ABAQUS software to validate the non-contact, video-based measured deflections captured by the dynamic motion and confirm the linear elastic behavior of the stem, following fundamental principles of engineering mechanics. Good agreement is found between the field data captured using video-based measurements and the physics-based FE model when a rotational connector element is connected at the base to quantify the 1) relative contribution and moment resistance provided by the root system, 2) displacement at any location along the stalk, and 3) flexural rigidity of the brace-stem system, where the rigidity can be associated with various phenotypes to design plant systems that are more resilient to lateral loading.Item Image-based assessment of plant disease progression identifies new genetic loci for resistance to Ralstonia solanacearum in tomato(The Plant Journal, 2023-01-10) Méline, Valérian; Caldwell, Denise L.; Kim, Bong-Suk; Khangura, Rajdeep S.; Baireddy, Sriram; Yang, Changye; Sparks, Erin E.; Dilkes, Brian; Delp, Edward J.; Iyer-Pascuzzi, Anjali S.A major challenge in global crop production is mitigating yield loss due to plant diseases. One of the best strategies to control these losses is through breeding for disease resistance. One barrier to the identification of resistance genes is the quantification of disease severity, which is typically based on the determination of a subjective score by a human observer. We hypothesized that image-based, non-destructive measurements of plant morphology over an extended period after pathogen infection would capture subtle quantitative differences between genotypes, and thus enable identification of new disease resistance loci. To test this, we inoculated a genetically diverse biparental mapping population of tomato (Solanum lycopersicum) with Ralstonia solanacearum, a soilborne pathogen that causes bacterial wilt disease. We acquired over 40 000 time-series images of disease progression in this population, and developed an image analysis pipeline providing a suite of 10 traits to quantify bacterial wilt disease based on plant shape and size. Quantitative trait locus (QTL) analyses using image-based phenotyping for single and multi-traits identified QTLs that were both unique and shared compared with those identified by human assessment of wilting, and could detect QTLs earlier than human assessment. Expanding the phenotypic space of disease with image-based, non-destructive phenotyping both allowed earlier detection and identified new genetic components of resistance.Item Maize brace root mechanics vary by whorl, genotype, and reproductive stage(Annals of Botany, 2022-03-03) Hostetler, Ashley N.; Erndwein, Lindsay; Ganji, Elahe; Reneau, Jonathan W.; Killian, Megan L.; Sparks, Erin E.Background and Aims: Root lodging is responsible for significant crop losses world-wide. During root lodging, roots fail by breaking, buckling, or pulling out of the ground. In maize, above-ground roots, called brace roots, have been shown to reduce root lodging susceptibility. However, the underlying structural-functional properties of brace roots that prevent root lodging are poorly defined. In this study, we quantified structural mechanical properties, geometry, and bending moduli for brace roots from different whorls, genotypes, and reproductive stages. Methods: Using 3-point bend tests, we show that brace root mechanics are variable by whorl, genotype, and reproductive stage. Key Results: Generally, we find that within each genotype and reproductive stage, the brace roots from the first whorl (closest to the ground) had higher structural mechanical properties and a lower bending modulus than brace roots from the second whorl. There was additional variation between genotypes and reproductive stages. Specifically, genotypes with higher structural mechanical properties also had a higher bending modulus, and senesced brace roots had lower structural mechanical properties than hydrated brace roots. Conclusions: Collectively these results highlight the importance of considering whorl-of-origin, genotype, and reproductive stage for quantification of brace root mechanics, which is important for mitigating crop loss due to root mechanical failure.Item Maize plants and the brace roots that support them(New Phytologist, 2022-09-14) Sparks, Erin E.Brace roots are a unique but poorly understood set of organs found in some large cereal crops such as maize. These roots develop from aerial stem nodes and can remain aerial or grow into the ground. Despite their name, the function of these roots to brace the plant was only recently shown. In this article, I discuss the current understanding of brace root function and development, as well as the multitude of open questions that remain about these fascinating organs.Item Root responses to abiotic stress: a comparative look at root system architecture in maize and sorghum(Journal of Experimental Botany, 2024-01-10) Hostetler, Ashley N.; de Sousa Tinoco, Sylvia Morais; Sparks, Erin E.Under all environments, roots are important for plant anchorage and acquiring water and nutrients. However, there is a knowledge gap regarding how root architecture contributes to stress tolerance in a changing climate. Two closely related plant species, maize and sorghum, have distinct root system architectures and different levels of stress tolerance, making comparative analysis between these two species an ideal approach to resolve this knowledge gap. However, current research has focused on shared aspects of the root system that are advantageous under abiotic stress conditions rather than on differences. Here we summarize the current state of knowledge comparing the root system architecture relative to plant performance under water deficit, salt stress, and low phosphorus in maize and sorghum. Under water deficit, steeper root angles and deeper root systems are proposed to be advantageous for both species. In saline soils, a reduction in root length and root number has been described as advantageous, but this work is limited. Under low phosphorus, root systems that are shallow and wider are beneficial for topsoil foraging. Future work investigating the differences between these species will be critical for understanding the role of root system architecture in optimizing plant production for a changing global climate.