ANALYZING THE EFFECTS OF DISRUPTING XYLAN ACETYLATION IN BRACHYPODIUM DISTACHYON

Open Access
Author:
Slovin, Justin Michael
Area of Honors:
Biology
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Daniel J Cosgrove, Honors Advisor
  • Charles T Anderson, Thesis Supervisor
Keywords:
  • Brachypodium
  • Plant Biology
  • Xylan
  • CRISPR
Abstract:
Plant cell walls are critical for growth and development, and also store carbon as energy rich, renewable biomaterial. Xylan is one of the principle structural hemicelluloses in the cell walls of most species of plants, including the model eudicot Arabidopsis thaliana and the model grass Brachypodium distachyon. Xylan acetylation, which is thought to be important for the interactions between xylan and other cell wall polysaccharides and can inhibit processing of cell walls for bioenergy production, is mediated by the acetyltransferase TRICHOME BIREFRINGENCE-LIKE 29 (TBL29), as well as TBL34 and TBL35. Affecting the expression of these genes decreases the overall amount of xylan acetylation in Arabidopsis thaliana, but homologs of these genes have not yet been functionally characterized in Brachypodium. Using both microRNA knockdown and CRISPR/Cas9 gene knockout methods, the expression of TBL29, TBL34, and TBL35 was interrupted. The results of growth experiments indicate that knocking out these genes results in stunted plants and drought stress symptoms in certain transformant lines, whereas knocking down the TBL29 gene does not result in stunting or drought stress symptoms through the T1 generation. The findings from this study lead to hope of being able to discover how the Brachypodium distachyon cell wall differs from the Arabidopsis thaliana cell wall, and how impeding xylan acetylation affects both organisms.