Proceedings of the XLV Italian Society of Agricultural
Genetics - SIGA Annual Congress
Salsomaggiore Terme, Italy - 26/29 September, 2001
ISBN 88-900622-1-5
Poster Abstract
POLYAMINES METABOLISM DURING SOMATIC EMBRYOGENESIS
IN VITIS VINIFERA L.
TASSONI A.*,
BERTOLDI D.*,**, MARTINELLI L.**, BAGNI N.*
* Dipartimento di Biologia e Centro Interdipartimentale
per le Biotecnologie, Università di Bologna, Italia
tassonia@alma.unibo.it
** Istituto
Agrario, San Michele all’Adige, 38010, Trento, Italia
grapevine, polyamines, somatic embryogenesis, Brachetto
g.l., Chardonnay
Aliphatic
polyamines are ubiquitous growth regulators affecting both in vivo
and in vitro plant growth and development, being involved in
several morphogenic processes related to their action in cell division.
With
the aim of better understand the developmental programs involved in
regeneration of grape plants, polyamine (putrescine, spermidine and spermine)
contents and polyamine biosynthetic enzyme activities, were assayed during
somatic embryogenesis induced in callus cultures obtained from Vitis
vinifera anthers (Chardonnay cultivar) or ovaries (Brachetto
a grappolo lungo cultivar). The analysis were conducted on samples of callus,
embryogenic callus, embryos at different stages (e.g. globular and torpedo) and
plants germinated from embryos. Polyamine content (nmol unit-1) both
free and conjugated to hydroxycinnamic acids (PCA-soluble fraction), resulted
higher in the cv. Brachetto g.l. than in the cv. Chardonnay, reaching the
highest levels in the fully-developed embryo stage (large embryos). In general,
putrescine was present in a greater amount with respect to spermidine and
spermine, in all the samples analysed. Ornithine decarboxylase (ODC) activity
was higher than arginine decarboxylase activity (ADC) in all the samples of
both cultivars, with a maximum in roots of germinated plants. Even
S-adenosylmethionine decarboxylase (SAMDC) activity displayed a similar trend.
All the activities were measured in the supernatant and in pellet fractions,
reconfirming the presence of ODC and ADC activity in the particulate fraction.
Contrarily to what generally stated in the literature, a consistent SAMDC
activity, was measured in the particulate fraction, being in particular
samples, such as roots of germinated plants, 50% higher than the SAMDC activity
in the soluble fraction.
Further analysis, by northern blot, are actually in
progress to evaluate the expression level of ADC, ODC and SAMDC transcripts, in
the different developmental stages of Brachetto g.l. and Chardonnay somatic
embryogenesis