Genetic and Hormonal Regulation of Stem Vascular Tissue Development In Flax (Linum usitatissimum L.)

• Author / Creator

  McKenzie, Ryan

• Flax (Linum usitatissimum) has been grown as a source of oil and fibre for several millennia. Linseed flax varieties are cultivated for their seed (flaxseed) and for their seed oils (linseed oil), which are used for many industrial applications. The fibres that form in linseed straws are generally considered too poor to make these industrial uses economical. In order to better understand how the flax stem and its component fibres develop, the effects of two plant hormones, gibberellin (GA) and auxin (indole-3-acetic acid, IAA), on stem tissue properties were examined. GA levels were determined to be a particularly important factor in many aspects of linseed stem development, including bast fibre cellular elongation and expansion. The spatial, temporal and hormonal-responsive expression patterns of five genes putatively involved in GA response (LuGAST1), GA biosynthesis (LuGA2ox1, LuGA3ox1), IAA response (LuIAA1) and IAA transport (LuPIN1) were also examined. A potential association of increases in LuGAST1 transcription with the cessation of bast fibre elongation and onset of secondary cell wall biosynthesis suggested a potential involvement of LuGAST1 in these processes. Through a mutant screen of an elite linseed cultivar, a novel mutant was identified, reduced fibre1 (rdf), which lacks a normal complement of fully differentiated fibres in its stem. The preliminary characterization of rdf shows that RDF function may be required for bast fibre elongation. Polymorphic simple sequence repeat (SSR) markers were also identified which will be useful in future for facilitating the cloning and sequencing of RDF through map-based cloning.

• Subjects / Keywords

  • Linseed
  • flax
  • bast fibre
  • xylem
  • gibberellin
  • auxin
  • gene
  • SSR

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3DK6Q

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.