© 2006 Heron Publishing—Victoria, Canada
Role of polyamines in peach fruit development and storage
Jihong Liu (1, 2), Kazuyoshi Nada (3), Xiaoming Pang (1), Chikako Honda (1), Hiroyasu Kitashiba (1) and Takaya Moriguchi (1, 4)
1. Department of Plant, Cell and Environment, National Institute of Fruit Tree Science, Tsukuba, Ibaraki 305–8605, Japan / 2. National Key Laboratory of Crop Genetic Improvement, National Center of Crop Molecular Breeding, Huazhong Agricultural University,
Wuhan 430070, China / 3. Faculty of Bioresources, Mie University, Tsu, Mie 514–8507, Japan / 4. Corresponding author (takaya@affrc.go.jp) / Received June 21, 2005; accepted August 22, 2005; published online March 1, 2006
Summary
To investigate the role of polyamines in pre- and post-harvest fruit development of ‘Akatsuki’ peach (Prunus persica (L.) Batsch.) we measured polyamine concentrations, activities of polyamine biosynthetic enzymes and expression of genes
encoding these enzymes. Concentrations of the free polyamines, putrescine (Put), spermidine (Spd) and spermine (Spm) in pre-harvest
fruit peaked 16 days after full bloom (DAF) and then progressively decreased until harvest with the exception of Put, which
showed a second peak at 94 DAF, just before the onset of ethylene production. In post-harvest fruit, minor changes in concentrations
of Spd and Spm were observed, whereas Put concentration peaked on the harvest day, followed by an abrupt decrease and a subsequent
2-fold increase, which was opposite to the fluctuating pattern of ethylene production. Activities of arginine decarboxylase
(ADC) and ornithine decarboxylase (ODC) peaked during the first stage of fruit development and then decreased until 80 DAF,
after which the activities were below detection limits, suggesting that Put is synthesized during the early stage of fruit
development. Activity of S-adenosylmethionine decarboxylase (SAMDC) decreased progressively until the end of S2. Expression levels of five putative
polyamine biosynthetic genes, ADC, ODC, SAMDC, spermidine synthase (SPDS) and spermine synthase (SPMS), in pre-harvest and post-harvest fruit did not coincide precisely with the observed changes in enzymatic activities and
polyamine concentrations. The possible role of polyamines during peach fruit development and the relationship between polyamines
and ethylene biosynthesis are discussed.
Keywords:
ethylene, gene expression, polyamine, polyamine biosynthetic enzymes, post-harvest, Prunus persica
.
