Abstract
Since phosphorous is a severely limited and nonrenewable resource, improvement of the ability of Pi-acquisition is an important goal in sustainable agriculture and forestry. Pi-acquisition in higher plants could be improved by modification of organic acid metabolism and in turn to enhancing organic acid excretion from the roots. A full-size cDNA encoding mitochondrial citrate synthase (mtCS) from carrot (Daucus carota L.) was introduced into a hybrid eucalypt (Eucalyptus grandis x urophylla) by Agrobacterium tumefaciens-mediated transformation. Several transgenic plants exhibited more than threefold greater level of CS activity than that found in the control plants. Western blot analysis revealed that ectopic mtCS proteins in the transgenic plants incorporated into the mitochondria. When aluminum-phosphate was supplied as a sole phosphorus source, growth rate and Pi content in the transgenic plants were greater than those of the control plants. It appears that the overexpression of mtCS improves Pi-acquisition ability in eucalypts.
