Page 6 - Molecular Plant Breeding

Molecular Plant Breeding 2011, Vol.2, No.16, 109-118
http://mpb.sophiapublisher.com
110
At present, lily commercial varieties mainly belong to
three hybrid species, that is Asian lily (Lilium Asian
hybrids), Oriental lily (Lilium Oriental hybrids) and
Easter lily (Lilium Longiflorum hybrids). It is easier to
succeed in hybrid breeding of intra-species but more
difficult to affinity of interspecies (van Tuyl et al.,
2000). However, hybrid of interspecies, such as OA
hybrid species, LA hybrid species and LO hybrid
species, usually has a much more ornamental value or
higher stress resistance, being worthy to be developed.
Regarding interspecies crossing, although in vitro
integrated technology was invented (integration of in
vitro pollination, in vitro ovary culture, in vitro ovule
culture and in vitro embryo rescue technology) (van
Tuyl et al., 1991), the hybrid success rate is still quite
low (van Tuyl et al., 2000) because the kinship of the
parents is too far leading to the directional growth
ability of paternal pollen tube in the maternal pistil is
greatly reduced, of which the pollen tube in upper part
of the style cannot occur directionally through lower
part of the style to the ovary, or the pollen tube in the
ovary cannot turn directionally toward the micropyle.
The functional studies of lily SCA genes promoting
the pollen tube adhesion and directional growth in
Lord’s laboratory attracted our research interesting, it
might be able to provide some helps to feature out the
mechanism of hybridizing barriers among lily species.
In order to feature out SCA gene structure and explore
the differences of the genes among the different
hybrid lines of lily, we chose one of the varieties
from Asian lily, Oriental lily, and Easter lily,
respectively, to isolate SCA genes as well as to
analyze the gene functions in this study, which might
provide some research basis to explain the mechanism
of hybridizing barriers.
1 Results and Analysis
1.1 Specific PCR amplification for Lily SCA
PCR amplification was performed with the primer of
LSCAF/LSCAR in three different varieties of lily
genomic DNA to generate the fragments with the
ranges from 500 to 700 bp in size (Figure 1). The PCR
products were cloned and sequenced. In this research
we obtained four different sequences from the Asian
Lily 'Tresor' and Oriental Lily 'Caruso', respectively,
as well as three different sequences from Easter lily
'White heaven'. Four sequences of the Asian lily were
named as LaSCA1, LaSCA2, LaSCA3 and LaSCA4
as well as the four sequences of Oriental lily named
LoSCA1, LoSCA2, LoSCA3 and LoSCA4, while the
three sequences of Easter lily was named LlSCA1,
LlSCA2 and LlSCA3.
Figure 1 SCA fragments amplified from lily genomic DNA by
SCA specific primers
Note: M: DNA Marker; A: Asiatic hybrids ‘Tresor’; L:
longiflorum hybrids ‘White heaven’; O: Oriental hybrids
‘Caruso’
1.2 DNA sequence analysis of lily SCA
In this research, the full length genes were amplified
by a pair of primer. The sequences compared with
SCA cDNA sequence of Easter lily 'Nellie white'
exhibited that the amplified genes containing two
exons and one intron (Table 1). The intron splicing
site was in line with the classic GT-AG rule (Figure 2).
In previous study, the LTP gene containing intron was
assigned to type Ⅰ, while the gene without intron
was assigned to type Ⅱ (Yubero-Serrano et al.,
2003). The obtained SCA genes would be type Ⅰ
gene, of which presented great variations in the intron
but quite conservation in the exons of the coding
region (Figure 2; Table 1). Eleven SCA gene
sequences were deposited in the GenBank with the
corresponding accession number (Table 1). Similarity
of 11 sequences was performed by using DNAMAN
to exhibit sequence similarity ranged from 72.97% to
99.68% (Table 2).