Anthocyanins and glutathione S-transferase activities in response to low temperature and frost hardening in Vaccinium myrtillus (L.).
Anthocyanin (Acy) contents and GST activities of bilberry (Vaccinium myrtillus L.) were investigated in two experiments conducted in June (Exp. I: active growth) and in August September (Exp. II: beginning of frost hardening) in Northern Finland (65 degrees N). Bilberry plants were subjected to +2 degrees C and +18 degrees C in Exp. I or +5/0 degrees C (day/night) and +18/+13 degrees C (day/night) in Exp. II. GST activities were assessed using either 1-chloro-2,4-dinitrobenzene (CDNB) or trans-cinnamic acid (tCA) as substrates. We found temperature to have no effect on Acy during either active growth or frost hardening. Acy increased several-fold from active growth to the beginning of frost hardening, but no increment was observed during the development of frost hardening. This suggests a role of Acy in photoprotection at low temperatures rather than their direct involvement in the development of freezing tolerance. The lack of response of GST activity to frost hardening and to temperature in autumn may indicate an indirect role of GSTs in frost hardening as protective enzymes. GST activity was the same with the two substrates studied (CDNB, tCA), supporting the assumption that GSTs could catalyze reactions with endogenous phenylpropanoids.
Taulavuori
Erja
E
Department of Biology, University of Oulu, P.O. Box 3000, Oulu FIN-90014, Finland. erja.taulavuori@oulu.fi
Tahkokorpi
Marjaana
M
Taulavuori
Kari
K
Laine
Kari
K
D000064:Acclimatization; D000872:Anthocyanins / Q000378:metabolism*; D003080:Cold Temperature; D005387:Finland; D005615:Freezing; D005982:Glutathione Transferase / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D012621:Seasons; D029800:Vaccinium myrtillus / Q000201:enzymology* / Q000254:growth & development
D000872:Anthocyanins; D010940:Plant Proteins; D005982:Glutathione Transferase