Does the expression of Arabidopsis thaliana acyl-coenzyme A-binding protein 6 mediate cold/freezing stress tolerance in transgenic canola?

Alahakoon AY1, Tongson EJ1, Meng W3, Ye Z3, Chye ML3, Golz JF2, Russell DA1 and Taylor PWJ1

  1. Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia.
  2. School of Biosciences, The University of Melbourne, Parkville, VIC, Australia.
  3. School of Biological Sciences, The University of Hong Kong, Pokfulam, Hong Kong.

Cold and freezing stress heavily affects the performance of canola (Brassica napus L.) crops in temperate countries, reducing seed yield and quality. To test the potential use of a low temperature stress mediating gene acyl-coenzyme A-binding protein 6 (ACBP6) from Arabidopsis thaliana in canola, rapid-cycling B. napus plants overexpressing the Arabidopsis ACBP6 were developed using Agrobacterium-mediated transformation. Four independent To lines confirmed as transgenic by western blot analysis and reverse transcription PCR were maintained to T3. These lines were tested for cold stress at vegetative stage and freezing stress at seed setting stage in non-acclimated and cold-acclimated conditions. The cold stressed ACBP6 vegetative plants recovered well and showed a higher yield potential than the cold stressed wild-type plants. Under both cold-acclimated and non-acclimated conditions the harvest index of three of the transgenic plants was around 0.20 while it was around 0.10 for wild-type plants and a single transgenic line. The percentage of fully viable seeds of freezing treated plants at the seed setting stage was significantly higher in transgenic plants (38-73%) than in wild-type plants (<27%). Cold-acclimation did not improve the cold stress tolerance of rapid-cycling plants, and indeed acted as an additional cold stress during the experiment. However, overexpression of Arabidopsis ACBP6 in canola is potentially useful in generating crops which are more tolerant to cold and freezing stress even in the absence of cold-acclimation.