Identification of Regulatory Mechanisms Underlying Cell Differentiation in Sorghum Biomass
Authors:
Wilfred Vermerris1* (wev@ufl.edu), Chris Dervinis1, Kelly Balmant1, Sushmita Roy2, and Matias Kirst1
Institutions:
1University of Florida; and 2University of Wisconsin
Goals
Researchers plan to alter the genetic regulation of the cellular developmental programs that generate the vegetative tissues of sorghum, with the aim to increase the proportion of cells that are less recalcitrant to biomass deconstruction.
Abstract
Plant biomass is comprised of distinct cell types, which largely determine its physical and chemical properties, and hence, its recalcitrance to biomass processing aimed at generating fermentable sugars that microbes can convert to biofuels. For example, the walls of parenchyma cells in the stalks of maize (Zea mays L.) and sorghum (Sorghum bicolor [L.] Moench) can be broken down using milder pretreatment conditions and with lower cellulase loadings than the lignified cells present in the outer rind of the stalk (Zeng et al. 2012; Zeng et al. 2012; Li et al. 2018). The different cell types within the sorghum plant develop from undifferentiated meristem cells through variation in the spatio-temporal expression of regulatory genes that control structural genes. The understanding of the role of specific genes and their regulation in this developmental process is incomplete. Uncovering the function of the complete ensemble of genes involved in the differentiation and maturation of the cells that make up sorghum biomass creates the opportunity to manipulate its cellular composition, impacting its physical and chemical properties and, consequently, its value for bioenergy.
Researchers propose applying single-cell genome and transcriptome analysis of the sorghum shoot apex and stem to identify the function of genes involved in differentiating cells that determine biomass composition. Inferred cell lineage trajectories involved in the development of the cellular components of biomass will be explored to discover their regulators. The specific objectives are to (1) define the function of each gene (including specific members within gene families) with respect to the development of the main cell types that determine sorghum biomass and its cell-wall composition; (2) construct the cellular lineages that give rise to each cell type that composes biomass (from the shoot apical and vascular cambium meristem cells to cells in the stem), and identify genes and cis-regulatory elements that contribute to the lineage progression; (3) categorize the function of gene and associated cis-regulatory components for their relevance in the control of cellular lineages that lead to each cell type, and (4) validate multiple targets in isolation and in parallel, to confirm their role in biomass development and their potential for enhancing biomass yield and its properties.
References
Zeng, M., et al. 2012. “Enzyme Hydrolysis and Imaging of Fractionated Corn Stalk Tissues Pretreated with Liquid Hot Water (Part 1).” Biotechnology and Bioengineering 109, 390–97. DOI: 10.1002/bit.23337.
Zeng, M., et al. 2012. “Enzyme Hydrolysis and Imaging of Fractionated Corn Stalk Tissues Pretreated with Liquid Hot Water (Part 2).” Biotechnology and Bioengineering 109, 398–404. DOI: 10.1002/bit.23335.
Li, M., et al. 2018. “Physical Fractionation of Sweet Sorghum and Forage/Energy Sorghum for Optimal Processing in a Biorefinery.” Industrial Crops and Products 124, 607–16.
Funding Information
This research is supported by the DOE Office of Science, Office of Biological and Environmental Research (BER), grant no. DE-SC0023082.