Characteristics of transgenic Eucalyptus hybrids with an overexpression of a plant mitochondrial citrate synthase

Abstract

Mitochondrial citrate synthase was overexpressed in Eucalyptus plant and its effects on organic acid excretion and low phosphorus tolerance were examined. The transformants and control plants were grown with a hydropoinc culture solution containing AlPO₄ as a sole phosphorus source. CS activity in roots of the transformants showed 1.4- to 2.5-fold increase in comparison with that in the control. Symptom of phosphorus deficiency was ameliorated in the transformants as judged form their phosphorus content. One transgenic line showed slightly higher (1.6-fold) citrate excretion than the control. This line was then grown with an acid soil containing insoluble phosphate and its growth tended to be slightly greater than that of the control. Therefore, it is suggested that overexpression of mitochondrial citrate synthase improves the growth performance of Eucalyptus plant under low phosphorus stress due to the high ability of phosphate-acquisition caused by the enhanced citrate excretion.