Xy. Xu et al., Stress-mediated effects on the expression of a predominant 18-kDa Taraxacum officinale root protein, PL PHYS BIO, 38(6), 2000, pp. 491-497
A predominant 18-kDa protein is present in the roots of dandelion (Tarauacu
m officinale Weber) which undergoes a small decline in amount in autumn and
a small increase in spring. This has led to the suggestion that the protei
n is a vegetative storage protein (VSP). Long-term photoperiod and temperat
ure changes applied to dandelion plants under controlled conditions did not
result in fluctuations in the amount of the 18-kDa protein in the root. A
rapid decrease in temperature from 20 to 5 degrees C (cold-shock) resulted
in an increase in the relative amount of the 18-kDa protein transcript, but
no change in the amount of the protein within the root. Conversely, a warm
-shock treatment (the transfer of plants from 5 to 20 degrees C) caused a d
ecline in the 18-kDa protein transcript, and a decline in the quantity of t
he 18-kDa root protein. Defoliation and wounding at 5 degrees C both stimul
ated an increase in the 18-kDa protein transcript within 36 h, but there wa
s no change in protein amount. Subjecting the plants to these perturbations
at 20 degrees C was without effect. The application of water stress to the
dandelion plants had no effect on the 18-kDa protein transcript, nor on th
e amount of protein present in the roots. These responses of the 18-kDa pro
tein and its gene are not consistent with those of known VSPs. (C) 2000 Edi
tions scientifiques et medicales Elsevier SAS.