ISSN 10227954, Russian Journal of Genetics, 2015, Vol. 51, No. 11, pp. 1069–1074. © Pleiades Publishing, Inc., 2015.
Original Russian Text © K.V. Boris, A.M. Kudryavtsev, E.Z. Kochieva, 2015, published in Genetika, 2015, Vol. 51, No. 11, pp. 1244–1249.
According to various taxonomic studies, genus
Mill. (Rosaceae) includes 25–47 cultivated and
wild species , the most important of which is the
domesticated apple (
world’s fourth largest fruit crop in terms of production
The unique feature of
species, along with
other Rosaceae fruit tree crops (genera
and others), is that, in contrast to other families of
higher plants, the end product of photosynthesis, in
addition to sucrose and starch, is sorbitol.
It was shown that sorbitol is the main carbohydrate
synthesized in leaves and transported to apple fruits
. As carbon source, sorbitol plays a key role in veg
etative growth of Rosaceae pome and stone fruits .
The supply and distribution of sorbitol is the key factor
in carbohydrate metabolism of fruits, that affects such
fruit quality traits as sugar–acid balance and starch
Furthermore, it was demonstrated that sorbitol is
involved in plant responses to abiotic stress, including
osmotic stress and exposure to low temperatures [5–7].
The key enzyme in sorbitol synthesis is sorbitol6
phosphate dehydrogenase (S6PDH), which converts
glucose6phosphate into sorbitol6phosphate. This
enzyme is localized in the cytosol and chloroplasts of
apple leaf cells .
At present, the fulllength sequence of the
gene, which encodes sorbitol6phosphate dehydro
genase, is known for only one representative of the
JF764598, 3595 bp;
, JF64599, 3402 bp) .
These sequences were mapped to chromosome X of the
genome and represented allelic variants
of the gene [8, 9]. The two sequences consist of six exons
and five introns and encode the proteins of 310 amino
acid residues. The main differences between them are
localised in introns III, IV, and V .
In studies of transgenic apple trees with both
increased and decreased
expression, it was
demonstrated that changes in the enzyme activity
affected the sorbitol/sucrose balance and their accu
mulation in leaves and altered the carbohydrate com
position of fruits [3, 4, 10, 11].
These data confirm the importance of sorbitol6
phosphate dehydrogenase for growth and formation of
Despite the key role of sorbitol6phosphate dehy
drogenase in fruit growth and development in
Rosaceae species, currently there are no data on the
S6PDH gene polymorphism in
study of the
intraspecific polymorphism in
is of special interest, as, in addition to a
more complete assessment of the genetic variability of
the members of the genus, it may also have practical
applications in breeding programs.
Sorbitol6Phosphate Dehydrogenase (
Gene Polymorphism in
K. V. Boris
, A. M. Kudryavtsev
, and E. Z. Kochieva
Vavilov Institute of General Genetics, Russian Academy of Sciences, Moscow, 119991 Russia
Bioengineering Center, Russian Academy of Sciences, Moscow, 117312 Russia
Biotechnology Department, Lomonosov Moscow State University, Moscow, 119234 Russia
Received April 17, 2015; in final form, May 28, 2015
—The sorbitol6phosphate dehydrogenase gene (
) sequences of six
five different taxonomic sections, were studied for the first time. The exonintron structure and polymor
phism of the nucleotide and amino acid sequences of these genes were characterized. The intraspecific poly
morphism of the
gene was assessed for the first time in 40 Russian and foreign apple (
) cultivars. It was demonstrated that the interspecific polymorphism level of the
in the studied
species was 4%, and the intraspecific polymorphism level in
very low (0.96%).
Keywords: apple, carbohydrate metabolism genes, sorbitol6phosphate dehydrogenase, genetic polymor