Open Collections

Hudson, Susan

An increasing global shift towards sustainable fuels has placed emphasis on the use of trees as potential bioenergy crops. For this to be economical, trees must be bred or designed to grow rapidly, efficiently, and to be easily processed into bioproducts. Cell walls are the components in trees that form the bulk of the raw materials that are converted to bioenergy products; therefore, understanding the genetic basis of the function, composition, and biosynthesis of cell walls is paramount for tree breeding for bioenergy and bioproduct production. An aspect of this strategy involves understanding the biosynthetic pathways that result in cell wall formation, including the involvement of several key proteins, such as those in the COBRA family. This paper reviews the importance of the cell wall to plants, details their structure and synthesis, as well as the role of the COBRA family of proteins in this process. Previous studies have shown that in Arabidopsis thaliana COBRA is associated with primary cell wall synthesis. Mutants with loss-of-function alleles in COBRA (cob-1) exhibit conditional root expansion defects, while mutants with null alleles (cob-4) exhibit sterility and stunted growth, suggesting the COBRA gene is integral to normal plant development in Arabidopsis, and specifically in cell elongation. A homolog of COBRA in Arabidopsis, COBRA-LIKE 4, has also been identified as having function restricted to secondary cell wall formation. To characterize the functional specialization and localization patterns of AtCOBL4, a promoter swapping experiment was proposed. This would involve the secondary wall-specific gene under regulation of the primary wall promoter, followed by an attempted recovery of the primary cell wall (COBRA) phenotypes in cob-1 and cob-4 mutants. Furthermore, a fluorescent protein fusion to AtCOBL4 was engineered to observe the protein localization under the regulation of the native promoter (PAtCOB) and visualization using laser microscopy. Localization of COBRA family orthologs such as PtCOBRA-3 (Populus trichocarpa) under the regulation of PAtCOB can also be observed using fluorescent protein fusion constructs. To perform these experiments, the following specific constructs were generated using a variety of molecular cloning techniques: PAtCOB::GFP, PAtCOB::AtCOBL4, PAtCOB::AtCOBL4-YFP, and PAtCOB::PtCOB3-YFP. These constructs were introduced into Arabidopsis wild-type, cob-1 and cob-4 mutants, all in the Columbia-0 background, and putative transgenic seed was generated. Future work will include genotyping, phenotyping, and confocal laser microscopy of the transgenic plants generated.

Graduating Project

eng

2014-10-08

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/50646

UBCV

Undergraduate

DSpace