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Developmental and Environmental Regulation of Bioenergy Sorghum Stem Growth
Abstract
The world population is increasing and becoming more industrialized, resulting in greater demands for energy. One approach to meet these needs is by improving the productivity of promising lignocellulosic biofuel crops, such as bioenergy sorghum. Sorghum is a versatile C4 grass with the ability to accumulate high amounts of biomass and thrive on marginal land, all while requiring minimal inputs. Elucidating the biochemical mechanisms of sorghum stem growth and development is an important step to further optimize biomass accumulation. The following three studies presented here utilize interdisciplinary techniques to expand our knowledge of sorghum developmental stages and further understand how sorghum responds to changes in the environment. First, the intercalary meristem in sorghum stems was localized to the base of elongating internodes and directly above the pulvinus using microscopy, MRI and developmental genetic analysis. An intercalary meristem gene regulatory network identified interactions between hormone-signaling and cell proliferation genes, providing a molecular framework to understand stem growth regulation. Second, the influence of shade on internode elongation was studied through field experimentation, hormone analysis and gene expression analysis. A hormone signaling pathway was developed to explain how changes in light perceived at the leaf is communicated to the stem, resulting in changes in growth. Finally, continued increase in stem density throughout the growing season is attributed to the accumulation of lignin and primary and secondary cell walls, after internode elongation. Lignin and secondary cell wall expression is localized to the rind early after elongation, while primary cell wall expression is uniform throughout the stem. These studies increase our understanding of the biochemical and molecular processes of sorghum stem development, growth, and biomass accumulation. Together, they will further the optimization of sorghum as a bioenergy feedstock.
Citation
Yu, Ka Man Jasmine (2022). Developmental and Environmental Regulation of Bioenergy Sorghum Stem Growth. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /198507.