Published by the Polish Society
for Horticultural Science since 1989
Folia Hort. 29/2 (2017): 99-111
http://www.foliahort.ogr.ur.krakow.plREVIEW Open access
As a result of its domestication, breeding and subsequent commercialization, African violet (Saintpaulia
ionantha H. Wendl.) has become the most famous and popular Saintpaulia species. There is interest in
producing cultivars that have increased resistance to pests and low temperature, in the introduction of novel
horticultural characteristics such as leaf shape, ower colour, size and form, and in improved productivity
and enhanced ower duration in planta. In African violet, techniques such as the application of chemical
mutagens (ethylmethanesulfonate, N-nitroso-N-methylurea), radiation (gamma (γ)-rays, X-rays, carbon ion
beams) and colchicine have been successfully applied to induce mutants. Among these techniques, γ radiation
and colchicine have been the most commonly applied mutagens. This review offers a short synthesis of the
advances made in African violet breeding, including studies on mutation and somaclonal variation caused by
physical and chemical factors, as well as transgenic strategies using Agrobacterium-mediated transformation
and particle bombardment. In African violet, Agrobacterium-mediated transformation is affected by the
Agrobacterium strain, selection marker, and cutting-induced wounding stress. Somaclonal variation, which
arises in tissue cultures, can be problematic in maintaining true-to-type clonal material, but may be a useful
tool for obtaining variation in ower colour. The only transgenic African violet plants generated to date with
horticulturally useful traits are tolerant to boron (heavy metal) stress, or bear a glucanase-chitinase gene.
Key words: Agrobacterium-mediated transformation, Gesneriaceae, mutation, particle bombardment,
somaclonal variation, transgenic
African violet (Saintpaulia ionantha H. Wendl.):
classical breeding and progress in the application
of biotechnological techniques
Jaime A. Teixeira da Silva1, Yaser Hassan Dewir2,3, Adhityo Wicaksono4,
Leela Sahijram5, Haenghoon Kim6, Songjun Zeng7,
Stephen F. Chandler8, Munetaka Hosokawa9
1 P.O. Box 7, Miki-Cho Post Ofce, Ikenobe 3011-2, Kagawa-Ken, 761-0799, Japan
2 Plant Production Department, P.O. Box 2460, College of Food & Agriculture Sciences
King Saud University, Riyadh 11451, Saudi Arabia
3 Department of Horticulture, Faculty of Agriculture, Kafrelsheikh University, Kafr El-Sheikh 33516, Egypt
4 Laboratory of Paper Coating and Converting, Centre for Functional Material
Åbo Akademi University, Porthaninkatu 3, 20500 Turku, Finland
5 Division of Biotechnology, Indian Council of Agricultural Research (ICAR) – Indian Institute of Horticultural
Research, Hessaraghatta Lake Post, Bangalore, Karnataka, 560 089, India
6 Department of Well-being Resources, Sunchon National University, Suncheon, 540-742, South Korea
7 Guangdong Provincial Key Laboratory of Applied Botany, South China
Botanical Garden, the Chinese Academy of Sciences, Guangzhou, 510650, P.R. China
8 School of Applied Sciences, RMIT University, Bundoora, Victoria, VIC 3083, Australia
9 Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
E-mail: email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org,
email@example.com, firstname.lastname@example.org, email@example.com, firstname.lastname@example.org.
Download Date | 8/4/17 2:48 PM
100 African violet breeding and progress in biotechnological techniques
African violet (Saintpaulia ionantha H. Wendl.;
Gesneriaceae) is the most famous and popular
Saintpaulia species. It has been domesticated,
bred and commercialized, and can be vegetatively
propagated fairly easily (Teixeira da Silva et
al. 2016a). A historical text by Tsukamoto et al.
(1982) indicates how the cultivation of Saintpaulia
originally started in Europe, but its development
as a horticultural plant took place in the United
States after World War II. Tsukamoto et al. (1982)
also noted that by 1981 there were about 20 species
in the genus Saintpaulia, although The Plant List
(2017) indicates that there are currently 25 species,
including accepted, synonymic and unresolved
This review offers a short synthesis of advances
made in mutation and somaclonal variation
caused by physical and chemical factors, as well
as transgenic strategies using Agrobacterium-
mediated t ransformation and pa rticle bomba rdment.
Classical breeding has the ability to transfer
a desired trait into different cultivars of any plant
species, but if one or more of the parent cultivars
used in cross-breeding are poorly adapted, then
a back-crossing strategy needs to be implemented
to recover the elite type. Moreover, poor combining
ability of some parental genotypes may occur and
doubled (i.e., multi-whorled) owers do not produce
male or female organs. For example, aromatic rice
varieties have poor combining ability, and cross-
breeding with non-aromatic varieties will lead to
a decrease in aroma and quality (Bourgis et al.
2008). Under such circumstances, the induction of
mutations can be advantageous to produce cultivars
with desired traits within dened germplasm
pools. Mutation breeding thus offers a solution to
difculties encountered in classical breeding. For
example, if genes conferring undesirable characters
are tightly linked to genes controlling desirable
traits, then induction of mutations may result in
a cross-over event or isolation of an independent
mutation for the desired trait (van Harten 2007).
Mutation breeding may be the only acceptable
way of classically increasing variability in plant
species that do not produce seeds (Ahloowalia
and Maluszynski 2001), and to develop novel
colours and variations in vegetatively propagated
ornamental plant species (Broertjes and van Harten
1988, Datta and Teixeira da Silva 2006, Kondo et
al. 2009). Thus, mutation breeding is considered to
be a valuable conventional breeding strategy.
Mutation techniques have made signicant
contributions in ornamental crop improvement.
Hundreds of mutant cultivars have been ofcially
released for various traits in horticulture, including
the colour and shape of owers and fruits, and
esh colour (Datta and Teixeira da Silva 2006).
However, plant breeders are under continuous
pressure to improve existing cultivars or to develop
new ones. Therefore, there is a need for newer
alternatives or technologies that, when combined
with conventional breeding methods, can help
create greater variability with desirable novel traits,
while reducing the time taken to do so. In vitro
culture of plant cells and organs generates genetic
variability (‘somaclonal variation’) resulting in
‘somaclones’ (regenerated plants that are not true-
to-type) which can be used in sexual hybridisation
for introgression of desirable alien genes into crop
species, or to generate variants of a commercial
cultivar at a high frequency without hybridizing it
to other genotypes (Larkin and Scowcroft 1981).
Ever since the rst formal report of morphological
variants in sugarcane plants produced in vitro in
1971, numerous somaclonal variations have been
reported in several horticultural crops (Krishna
et al. 2016). Somaclonal variation manifests itself
as qualitative or quantitative phenotypic changes,
sequence changes, and gene activation/silencing
(Kaeppler et al. 2000). Epigenetic changes occur via
changes in DNA methylation patterns, activation
of quiescent transposable elements (TEs) or
retrotransposons (Duncan 1997, Huang et al. 2009).
In important horticultural crops, DNA methylation
patterns are highly variable among regenerants
and polymorphisms exist in somaclones (Sahijram
2014, 2015). In African violet, 47% of somaclonal
variants from in vitro cultures did not ower. No
variation was seen in ower colour in the remaining
owering plants (Jain 1993a, 1993b, 1997a, 1997b),
although these studies did not assess genetic
It is possible to induce variation in ower
colour and introduce several other novel traits to
ornamental plants using somaclonal variation.
Often, a plant regeneration system, particularly
callus-mediated plant regeneration, introduces
variations that may be heritable (Krishna et al.
2016). The concentration and combination of plant
growth regulators (PGRs), as well as subculture
frequency and duration, also result in a higher
frequency of variation (Matsuda et al. 2014). TE
transposition and a combination of factors such as
colchicine, gamma (γ)-rays, ion-beams, and PGRs,
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 101
may serve as a good set of tools for expanding
variations in ower colour in African violet.
Saintpaulia owers are zygomorphic with two
upper and three lower lobes. The upper two lobes
are smaller than the lower ones. Saintpaulia has
a very short corolla tube and yellow protruding
anthers that are probably associated with buzz
pollination (Harrison et al. 1999). The anthers of
Saintpaulia have only one chamber, the owers have
a distinct disk, the style and stigma usually have the
same colour as the petals, and the ovary is exserted
slightly to the left or right of the center of the corolla
(Harrison et al. 1999). All Saintpaulia species are
enantiostylous (the style is strongly deected to
the left or right of the main oral axis), a feature
often linked to buzz pollination S. ionantha is
a protandrous species, and the anthers appear to be
full of pollen, even during the pistillate phase. The
anthers do not wilt, remain yellow and have thecae
and stiffened walls (Vogel 1978). Most Saintpaulia
species can hybridize with their congenerics and
produce fertile hybrids (Arisumi 1964).
The diploid chromosome number in African
violet was indicated by Vazquez et al. (1977),
Espino and Vazquez (1981) and Sun et al. (2010)
to be 2n = 28. Farjadi-Shakib et al. (2012) were
of the opinion that since African violet had tiny
chromosomes with a propensity for sticking
together and a centromere difcult to distinguish,
the diploid chromosome number in this species
was incorrectly described as 2n = 2x = 28 (Sugiura
1936, Adisorn 2004). More detailed cytological
analyses indicated that the diploid chromosome
number was 2n = 2x = 30 (Ehrlich 1956, Farjadi-
Shakib et al. 2012), and 2n = 60 for the tetraploid
hort. var. ‘Ionantha Amazon’ (Ehrlich 1958), with
a total genome length of 29.995 µm, and a ratio
of the longest to the smallest chromosome of 2.77
(Farjadi-Shakib et al. 2012). Using ow cytometry,
Loureiro et al. (2007) determined that the nuclear
DNA content (i.e., genome size) of diploid
S. ionantha was 2C = 1.5 pg.
Spontaneous self-pollination has been reported
to occur frequently in some commercial African
violet cultivars through an abnormal mode of ower
development in which the stigma grows into the
anther (Anonymous 2002). Self-fertilization and
mating between close relatives in small populations
may lead to inbreeding depression (Charlesworth
and Charlesworth 1987, Kolehmainen and
Mutikainen 2006). Kolehmainen et al. (2010)
investigated inbreeding depression in 12 populations
of a threatened, endemic African violet, S. ionantha
ssp. grotei, using one microsatellite locus, and
concluded that inbreeding occurred frequently and
led to signicant inbreeding depression.
2. Interspecic crosses
Saintpaulia is likely to predominantly outcross
because it is pollinated by ying insects and
because the owers have two different stylar
morphs (i.e., enantiostyly), which has been shown
to promote cross pollination (Jensson and Barrett
2002). Crossing experiments have shown that the
majority of Saintpaulia taxa can hybridize and that
hybrid offspring are fertile (Clayberg 1961, Arisumi
1964). However, Afkhami-Sarvestani et al. (2012a)
were unable to produce viable progeny, even using
embryo rescue, from intergeneric crosses between
Streptocarpus sub-genus Streptocarpella and
S. ionantha. Af khami-Sarvestani et al. (2012b)
were able to induce callus after fusing protoplasts.
Arisumi (1967) conducted a large breeding
experiment in which he selfed and crossed
several clones of Saintpaulia species that had no
anthocyanin in their leaf blades, namely, according
to the Interagency Taxonomic Information System
& World Checklist of Gesneriaceae, S. amaniensis
E. Roberts [now accepted as S. ionantha ssp. grotei
(Engler) I. Darbysh, taxonomic serial No. (TSN)
832566], S. confusa B. L. Burtt. [now accepted as
S. ionantha ssp. grotei (Engler) I. Darbysh, TSN
832554], S. difcilis B. L. Burtt. [now accepted as
S. ionantha ssp. grotei (Engler) I. Darbysh, TSN
832556], S. diplotricha B. L. Burtt. [now accepted
as S. ionantha var. diplotricha (B.L. Burtt) I.
Darbysh., TSN 832560], S. grandifolia B. L. Burtt.
[now accepted as S. ionantha ssp. grandifolia (B.L.
Burtt) I. Darbysh, TSN 832561], S. grotei Engl.
[now accepted as S. ionantha ssp. grotei (Engler)
I. Darbysh., TSN 832562], and S. magungensis E.
Roberts [now accepted as S. ionantha ssp. grotei
(Engler) I. Darbysh., TSN 832616] (Skog and Boggan
2010, ITIS – available online at: https://www.
itis.gov). After germinating seeds and growing
seedlings according to Arisumi (1964), Arisumi
(1967) determined genetic ratios after assigning
the symbols A and a, respectively, to dominant
and recessive genes for anthocyanin. Arisumi
(1967) found that: a) A and a segregated in classic
Mendelian ratios; b) S. diplotricha (syn. S. ionantha
var. diplotricha) was homozygous recessive (aa),
whereas all the other species were heterozygous
Download Date | 8/4/17 2:48 PM
102 African violet breeding and progress in biotechnological techniques
(Aa); c) the A gene might control anthocyanin
production in L-I, L-II and L-III layers; d) S.
ionantha ‘Snow Prince’ and ‘Northern Snowake’
had a recessive gene for white ower colour which
prevented the formation of anthocyanin anywhere
in the plant. Arisumi and Frazier (1968) induced
a single chimeric polyploid plant from 29 regenerants
after treating leaf cuttings with colchicine.
After intensive breeding over the past century,
thousands of cultivated Saintpaulia varieties are
mass propagated by the horticulture industry
(Baatvik 1993). These cultivars have mainly been
bred from two natural species, S. ionantha and
S. confusa (S. ionantha ssp. grotei) (Baatvik 1993,
Eastwood et al. 1998).
3. Ploidy and polyploidization
Espino and Vazquez (1981) regenerated polyploid
and mixoploid plants from leaf explants using
caffeine or colchicine, but no polyploidy was
detected in regenerants grown on control medium.
More specically, exposure of leaf explants to basal
Murashige and Skoog medium containing 500 or
1000 mg l-1 caffeine for 4-16 days resulted in 2-8%
polyploid plants (including chimeric plants), whereas
exposure to 100-200 mg l-1 colchicine resulted in
22-46% polyploids. Their results were in contrast
to the low level of mixoploidy (1-2%) observed by
Broertjes (1974) when petioles and leaves were
exposed to colchicine. Winkelmann and Grunewaldt
(1995) conrmed that 16% of regenerants derived
from protoplast culture were polyploid (mostly
tetraploid). Seneviratne and Wijesundara (2003)
applied 0.05% colchicine for 18 h to leaves of
four unspecied African violet varieties, and
succeeded in producing dwarf plants with small,
succulent leaves with a short petiole, suitable for
use as table-top miniature plants. Bhaskaran et al.
(1983) obtained anther-derived plants that were not
haploid, but diploid or tetraploid, possibly due to the
endomitosis during tissue culture.
4. Mutation breeding and chimeras
Periclinal chimeras were observed in pinwheel
owering African violet varieties (Lineberger and
Druckenbrod 1985) and several breeding-oriented
mutations have been reported in Saintpaulia. Several
techniques are available to induce mutations in
ornamental plants, including chemical and radiation
(γ- or X-ray irradiation, ion-beam treatment) or
TE activation (Datta and Teixeira da Silva 2006).
Sparrow et al. (1960) suggested that chimeras
originating from a low percentage of S. ionantha
mutants (0.7%) might be of multicellular origin.
4.1. Chemical mutagenesis
Wareld (1973) produced 13% mutations
after treating petioles of leaf cuttings of
S. ionantha (cultivar not specied) with 0.5 M
ethylmethanesulfonate (EMS) for 1 h, including
leaf-patterning mutants, leaf colour variants, and
dwarf plants. Except at a lethal dose, Kelly and
Lineberger (1981) found that thermal neutron
irradiation (250, 1000 and 5000 Rad of thermal
neutrons) of cuttings reduced root emergence and
induced changes in peroxidase proles, but did not
induce any morphological mutants. By applying
400 mg l-1 N-nitroso-N-methylurea (NMU) to in
vitro leaves (Geier 1983), leaf albinism and mottling
could be induced; this could be increased to 50%
when 0.1-1.0% dimethyl sulfoxide was added. In
the same study, exposure to 97.45 or 292.36 mM
EMS produced different levels of shoot inhibition
and chlorophyll-decient shoots relative to controls
and NMU-treated leaves (Tab. 1). Grunewaldt
(1983) observed that as many as 40% of regenerants
from NMU-treated leaf explants showed altered
leaf pigmentation. Gaj and Gaj (1996) induced
chlorophyll chimerism (variegated leaves) in
100% of explants when leaves were treated with
5 nM NMU for 1.5 or 2 h. In all of these studies,
stable transmission of mutations from one clonal
generation to the next was not possible. Leaf
blade and petiole cuttings of S. ionantha ‘Ulery’
exposed to thermal neutron irradiation (250-5000
Rad) did not generate any morphologically distinct
mutants, although variation in peroxidase levels
4.2. Physical mutagenesis (radiation)
Using an unnamed cultivar, Seneviratne and
Wijesundara (2007) reported a change in ower
colour pattern (white petals with wide, pink
margins) by coupling 15 Gy of γ irradiation with
a dip treatment of leaves bearing 2.5 cm long
petioles in 0.06% colchicine for 22.5 h. The same
treatment resulted in a change in plant architecture,
measured as reduced petiole length (3.9 cm vs
8 cm in the control), reduced leaf surface area
(14.7 cm 2 vs 34.8 cm2 in the control), smaller ower
diameter (2.1 cm vs 3.8 cm in the control) and
shorter inorescence height (3.7 cm vs 6.4 cm in
the control). In their experiment, all the plants died
after γ irradiation of 20 Gy. Wongpiyasatid et al.
(2007a, 2007b) tested γ-ray (0-100 Gy) treatment of
leaf cuttings of two unnamed cultivars of African
violet (Wongpiyasatid et al. 2007a) or ‘Optima
Hawaii’ (Wongpiyasatid et al. 2007b). The LD50(60) ,
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 103
which indicates 50% dead leaves at 60 days after
irradiation, was 56 Gy, and the highest frequency
of mutation (18.33%) occurred when 60 Gy was
applied; irradiation exceeding 80 Gy caused the
death of all leaves. Vegetative and oral mutations
induced changes in plant canopy width, number
of leaves, number of inorescences per plant,
number of owers per inorescence, and ower
form, colour and size. For example, at 60 Gy, 24.9
leaves/plant were formed versus 20.5 in the control.
In a few cases (Wongpiyasatid et al. 2007a), there
was conversion from a vegetative meristem into
a oral meristem and subsequent formation of
an inorescence in place of leaves. According
to Wongpiyasatid et al. (2007a), detached leaves
exposed to X-rays and fast neutrons also showed
dose-dependent mutagenesis (Broertjes 1968,
1971, 1972). Zhou et al. (2006a, 2006b) irradiated
adventitious shoots in vitro with carbon ion beams
and X-rays, and found that 49.6% and 43.3% of
‘Mauve’ and ‘Indikon’ shoots, respectively, were
malformed in response to carbon ion beams, but
only 3.7% and 11.3% following X-ray irradiation.
Somaclonal variation as a result of tissue culture
In vitro leaf and petiole homogenate cell clusters of
S. ionantha ‘Crimson Frost’ were used for studies
on somaclonal variation (Paek and Hahn 1999). The
resulting plants showed variations in leaf colour
(67% of variants) and leaf shape (19% of variants),
but no difference in protein proles was observed
using SDS-PAGE. Semi-double and double ower
types were more common than the single ower
type, showing 81% normal (mixed) colour vs. pink,
red or white (19% of variants) (Paek and Hahn 1999).
Their results indicate that the use of homogenate
cell clusters was not a proper method for true-to-
type propagation of African violet. In Saintpaulia
‘Thamires’ (Saintpaulia sp.), ower colour variants
in tissue culture-derived regenerants were formed
due to the excision of a TE (Sato et al. 2011a, 2011b).
Much of the variability seen in micropropagated
plants may be either the result of, or may be related
to, oxidative-stress damage in plant tissues during
in vitro culture (Matsuda et al. 2014). Simply
by culturing leaf explants in vitro, Shajiee et al.
(2006) were able to induce variegated leaves in a
maximum of 0.78% of regenerants in one of the
In Saintpaulia, somaclonal variation is
considered problematic when clonal (true-to-type)
material is desired, as indicated by the studies
above, but is also very useful for improving traits.
Sato et al. (2011b) identied a hAT superfamily TE
(VGs1) in the avonoid 3', 5' hydroxylase (F3'5'H )
promoter region and found that when the TE was
Table 1. Key results from Geier (1983) (modied) showing the impact of 1 h exposure of two chemical mutagens,
N-nitroso-N-methylurea (NMU) and ethylmethanesulfonate (EMS), on shoot inhibition and production of chlorophyll-
decient shoots in ‘Rhapsodie 26’ at 73 days of treatment
Treatments Rinse (H2O)
Number of shoots per
Inhibition of shoot
Control* 43.3 0.00 0.00
1% (97.45 mM) 3 × 2 17.6 59.35 1.14
3 × 20 23.8 45.03 0.84
3% (292.36 mM) 3 × 2 5.6 87.99 1.92
3 × 20 20.1 53.58 1.49
Control 38.0 0.00 0.00
400 mg l-1 (3.88 mM) 3 × 2 10.9 71.91 12.84
3 × 20 19.6 49.48 8.67
800 mg l-1 (7.76 mM) 3 × 2 3.5 90.98 20.00
3 × 20 7.6 80.41 18.42
Control 51.6 0.00 0.00
200 mg l-1 (1.94 mM) Undened 38.3 25.78 4.44
400 mg l-1 (3.88 mM) Undened 24.0 46.51 8.33
600 mg l-1 (5.82 mM) Undened 9.8 81.00 14.29
800 mg l-1 (7.76 mM) Undened 6.0 88.37 20.00
*No chemical mutagen treatment
Download Date | 8/4/17 2:48 PM
104 African violet breeding and progress in biotechnological techniques
excised from this region, ower colour changed from
pink to purple (Fig. 1). In Saintpaulia ‘T h am ire s’,
Sato et al. (2011a) concluded that the origin of
somaclonal variation could be mainly attributed to
‘newly induced mutations’. Matsuda et al. (2014)
tried to identify factors involved in the induction of
transposition of VGs1, and plant growth regulators
added to the culture medium were candidate factors
for the induction of somaclonal variation.
1. Molecular and biochemical regulation
The genetic control of ower initiation and ower
development, and the molecular mechanisms that
are responsible for the regulation of these processes
have been studied in detai l (reviewed in Stewar t et al.
2016). Saintpaulia has been included in some of these
studies. Wang et al. (2006) isolated two CYC-like
genes, SiCYC1A and SiCYC1B, from zygomorphic
and actinomorphic cultivars respectively, of
S. ionantha, using mTAIL-PCR. The two SiCYC1A
genes contained the entire regulatory domains
(i.e., TCP and R domains) that were functional
in establishing oral symmetry, and these were
homologous with the Antirrhinum majus CYC gene.
Unexpectedly, the two SiCYC1B genes from the
actinomorphic cultivar had a sequence identical to
genes from the zygomorphic cultivar. Comparative
analysis of molecular alterations in CYC-like genes
responsible for morphological transformation from
zygomorphy to actinomorphy indicated that the
two closely related SiCYC1A and SiCYC1B genes
were perhaps regulated by a common, upstream
regulator. Change in this regulator could result in
the silencing of both SiCYC1A and SiCYC1B, thus
Figure 1. Schematic representation of F3'5'H and its promoter region (not to scale). Variegated individuals (a) have
two types of F3'5'H (avonoid 3',5'-hydroxylase) sequences: one has a 3844-bp insertion and the other appears to
have a post-excision sequence (see c). Solid-pink mutants (b) also have two types of sequences: one has imperfect
transposon insertion and the other has erratic post-excision sequences varying from 58 to 70 bp. Solid-blue mutants
(c) have a sequence with an 8-bp footprint. Deep-purple (d) and solid-purple (e) mutants have sequences lacking 21-
and 24-bp regions, respectively, compared to the solid blue mutant (see: c). Accession numbers (GenBank): transposon
VGs1 – AB596833, solid pink – AB596835-AB596837, solid blue – AB596834, deep purple – AB596838, solid purple
– AB596839. Figure modied from Sato et al. (2011a,b) and Matsuda et al. (2014). L*, a*, b* – refers to the Hunter
colour scale (Hunter 1948)
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 105
controlling the development of the adaxial and
lateral organs in a ower.
Pei et al. (2012) reported that the range of pH
values in cellular sap of the linguoid petal in blue
and white ower S. ionantha cultivars was 3.0 to
7.0. The pH value (6.21) of the blue ower cultivar
was higher than that of the white ower cultivar
(pH 3.32) on the rst day of owering and increased
when the owering period was extended from 1 to
20 days. The changes were greater in the white
cultivar than in the blue cultivar. On the 20th day of
owering the pH value was 6.64 in the blue cultivar
and 4.21 in the white cultivar.
2. Genetic modication
Genetic modication of ornamental plants is an
important means of introducing new characters
such as modied ower colour, leaf shape or plant
architecture (Teixeira da Silva et al. 2016b). The
technology for genome editing has progressed
considerably in recent years, and using techniques
such as CRISPR/Cas9 (Samanta et al. 2016) it
is now possible to knock out a specic gene or
to target a specic position on the genome for
genetic modication. Now in its infancy, articial
chromosome technology offers an opportunity
for multiple gene transfer in the future as part of
a genetic engineering strategy (Yu et al. 2016).
It seems that genetic transformation could also
help create plants resistant to Melodogyne arenaria
Thamesii, a root-knot nematode known to infect
the roots of potted S. ionantha plants (Goidanich
and Garavini 1959).
2.1. Transformation of Saintpaulia
Several researchers have reported the production
of transgenic Saintpaulia plants. Kushikawa et
al. (2001) succeeded in Agrobacterium-mediated
transformation of S. ionantha. After testing
Agrobacterium strains LBA4404 (plasmid
pTOK233), EHA101 (pIG121 hygromycin) and
LBA4404 (pIG121 hygromycin), positive results
were obtained for LBA4404. In their experiment,
a suspension culture of Saintpaulia ‘Pink Veil’
was exposed to LBA4404 for 48 h, and after
4 months of culture on selection medium containing
50 mg l-1 hygromycin, hygromycin-resistant callus
was obtained. Transgenic plants harbouring the
gusA gene were conrmed by PCR and Southern
blot analysis, although the number of transgenic
plants produced and the transformation efciency
were not indicated. No transformants were derived
directly from leaves but only via callus. Using the
same plasmid constructs as in their 2001 study,
Kushikawa et al. (2002) were able to increase the
number of GUS foci by co-cultivating leaf explants
with 300 µM acetosyringone. Mercuri et al. (2000)
obtained transgenic Saintpaulia ‘Rhapsody’ plants
using A. tumefaciens oncogenic strain A281 after
infecting petiole slices (3-10 mm thick), but no
plants were recovered from co-cultivated leaves.
No success was obtained when the disarmed strain
EHA105 was used. In their protocol, 30-min.
co-culture with Agrobacterium followed by the
culture of explants in the dark on selection medium
containing 100 mg l-1 kanamycin resulted in high
(90% of explants) transient GUS gene expression
after 3 days, reduced expression (30% of explants)
after 15 days, and no expression after 25 days.
The GUS gene was not detected by PCR in all the
GUS-positive plants tested, but the nptII gene was
detected in Southern blot analysis, suggesting either
loss of the transgene, or transgene silencing. Ram
and Mohandas (2003) used LBA4404 harbouring
pBINAR carrying a glucanase-chitinase gene to
transform Saintpaulia ‘Sailors Delight’ leaves after
co-cultivation for 5 min., and following culture in
the dark in the presence of 70 mg l-1 kanamycin.
A high percentage (75%) of putative transformants
showed a signal for the glucanase gene in Southern
blot analysis. Ohki et al. (2009) suggested
that Saintpaulia varieties ‘Heavens A-calling’,
‘Kris’, and ‘New Mexico’ leaf explants dipped in
a solution of A. tumefaciens (pIG121HM) should be
cultured at a minimum of 30 mg l-1 hygromycin for
selection. Ye et al. (2014) genetically transformed
the AtTIP5;1 gene (a highly expressed Arabidopsis
pollen-specic gene related to aquaporin) into
the leaves of an unspecied S. ionantha cultivar
using A. tumefaciens strain GV3101. The authors
found that pre-culture for 2 d on non-selective
shoot induction medium, infection for 15 min., co-
culture for 2 d with 100 µmol l-1 acetosyringone
and selection with 40 g l-1 hygromycin were the
optimal transformation conditions. After screening
with PCR and RT-PCR, 17 transformed plants
containing the AtTIP5;1 transgene were obtained.
Tra nsfor med AtTIP5;1 plants showed improved
tolerance to boron stress.
In addition to the Agrobacterium strain and
the selection marker used, the stress caused by
cutting the explants is important for Agrobacterium
infection since S. ionantha plants are very sensitive
to local wounding of leaves (Yang et al. 2002).
Wounding of leaves induces a hypersensitive
state in explants, such as the leaves of the species
of the Acanthaceae and Gesneriaceae, including
Download Date | 8/4/17 2:48 PM
106 African violet breeding and progress in biotechnological techniques
Saintpaulia sp., resulting in the browning of
unwounded areas within 30 min. as a result of
secondary wounding (Yang et al. 2002, 2003,
2006). Therefore, leaf wounding, such as that
caused during the preparation of leaf segments, may
have a negative effect on Agrobacterium infection.
Ghorbanzade and Ahmadabadi (2015) used particle
bombardment to genetically transform a local
Iranian cultivar of African violet with the GUS
gene. An endochitinase gene was then introduced
and stable integration was conrmed by PCR and
RT-PCR in 4 out of 7 lines.
2.2. Flower colour modication in transgenic
Depending on the variety, Saintpaulia owers
produce delphinidin-, cyanidin- and/or pelargonidin
-based anthocyanins (Griesbach 1998, Tatsuzawa et
al. 2012, Tat su z awa and Hos o k awa 2016 ). Cyan id in -
based anthocyanins accumulate in the leaves of
some varieties, imparting a deeper, but less green
colour to the leaves (Arisumi 1967). Chalcone-
based avonoids have been shown to be the yellow
pigment present in yellow owers (Deguchi et al.
Molecular analysis has shown that there are
two distinct chalcone synthase (CHS) genes in
the Saintpaulia genus, SaCHSA and SaCHSD
(Caro et al. 2006). CHS codes for the rst enzyme
in the avonoid production pathway. Using
phylogenetic analysis, the CHS genes have been
used to differentiate several Saintpaulia species
[S. grandifolia (S. ionantha ssp. grandifolia),
S. grotei (S. ionantha ssp. grotei), S. intermedia
(S. ionantha ssp. pendula (B.L. Burtt) I. Darbysh.
TSN 832528), S. ionantha and S. orbicularis
(S. ionantha ssp. orbicularis (B.L. Burtt) I. Darbysh.
TSN 832596] (Caro et al. 2006). Jiao et al. (2014)
cloned the avonoid 3',5'-hydroxylase (F3′5′H ) gene
from S. ionantha (cultivar not indicated) and found
maximum homology among S. ionantha cultivars,
and also with Antirrhinum kelleggii and Torenia
hybrida. Sense F3′5′H expression vectors were
transformed into tobacco using A. tumefaciens
strain LBA4404. In transgenic tobacco, the
avonoid content detected using HPLC was 4.0-
16.3% higher than that in the wild type (1.76%), and
owers were light purple.
Despite the large palette of colours available
amongst African violet varieties, there are still
colour modications that would be very valuable
PAL, 4CL, CHS
In sertion of auron e
bi osynthesis genes
RNA i o r co-s uppres sion to
bl ock anthocyanin
bi os ynthesis
D o wn regu la tion o f F 3’5 ’H to
l ead to 100% cya nidin-base d
a nt ho cyani ns
Cyanidin Pelargonidin Delphinidin
Peonidin Petunidin, malvidin
Red flowers Purp le violet flowers
Figure 2. Schematic representation of the ower pigment biosynthesis pathways in Saintpaulia showing (lled text
boxes with grey-light blue) the points at which genetic modication could be applied. In this simplied diagram, key
enzymes are abbreviated as follows: PAL – Phenylalanine ammonia lyase, 4CL – 4-Coumarate-CoA ligase, CHS
– chalcone synthase, CHI – chalcone isomerase, F3H – avanone 3β-hydroxylase, F3'H – avonoid 3’-hydroxylase,
F3'5'H – avonoid 3’,5’-hydroxylase
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 107
in Saintpaulia and which can only be achieved
through genetic engineering. Broadly, the rst
strategy would be to increase the colour range in
a single, very high quality variety, as was done
using genetic engineering in torenia (Nishihara
et al. 2013). The second strategy would be to use
genetic engineering for the generation of colours
not found in the species, such as a true red (van
Schaik and Newlands 1963) or deep yellow. Aside
from an undetailed report of a European eld trial
in 2001 (Cadic and Widehem 2001), ower colour
modication by genetic engineering has not yet
been demonstrated in Saintpaulia, although there
are multiple theoretical avenues for ower colour
modication in this genus, as illustrated in Figure
2. In summary, avenues that may be explored alone
or in combination are:
• In white-owered varieties, including
coloured varieties in which the anthocyanin
pathway has been down-regulated, transfer
of betalain pigment biosynthesis genes for
the production of novel yellow aurone-based
pigments (Ono et al. 2006).
• Up and/or down regulation of the avonoid
hydroxylase genes on the existing
anthocyanin pathway to alter the type and/
or ratio of anthocyanins accumulated. As
an example of such a strategy, to produce
a ‘true red’ variety, the anthocyanin pathway
could be manipulated to produce varieties
that only accumulate red cyanidin-based
• Manipulation (through methylation or
glycosylation) of the secondary structure
moieties of existing anthocyanins to alter
spectral qualities and thus ower colour
(Tatsuzawa and Hosokawa 2016).
• Down-regulation of endogenous chalcone
synthase genes to block anthocyanin
biosynthesis. With suitable promoters this
strategy could also be used to alter leaf colour
by inhibiting anthocyanin accumulation in
the leaves of affected varieties.
Radiation- or colchicine-induced mutagenesis has
served as a useful tool to broaden genetic diversity
in African violet, a vegetatively propagated
ornamental species. As described in several papers
in this review, at the research level mutation breeding
and tissue-culture induced somaclonal variation
have led to several changes in African violet plant
architecture, including petiole length, surface area,
ower diameter, inorescence height and number
of leaves and inorescences per plant. Several
economically desirable traits such as ower colour
pattern, chlorophyll chimerism and dwarng have
also been observed in African violet using radiation
and chemical mutagens. These traits can be stably
propagated through vegetative means, including
leaf culture (Teixeira da Silva et al. 2016a). African
violet plants are very sensitive to alteration in light
intensity, temperature, and humidity, and minor
changes can lead to the development of leaf spot
disease (Yun et al. 1997, Yang et al. 2001, Chen and
Henny 2009). Plants resistant to biotic and abiotic
stresses will need to be developed using transgenic
strategies, and this requires robust and reproducible
genetic engineering and tissue culture protocols
to regenerate transformants. These techniques
are now available. Agrobacterium-mediated
genetic transformation has been shown to alter
Saintpaulia genetic makeup by the introduction of
a glucanase-chitinase gene (Ram and Mohandas
2003). Transformants with improved tolerance
to boron stress have also been obtained (Ye et
al. 2014). Genetic modication is also a tool that
can be used to generate novel ower colours in
Saintpaulia. However, to date, transgenic varieties
of African violet have not been commercialised.
Given the complexity of the regulatory processes
associated with the release of transgenic plants,
our expectation is that conventional breeding
methods, including mutagenesis, will thus continue
to dominate the product pipeline for African violet.
The conservation of wild Saintpaulia species will
continue to be a priority, and the best way to achieve
this is through in vitro propagation (Teixeira da
Silva et al. 2017). Molecular methods to classify
germplasm (Teixeira da Silva et al. 2007) will need
to be developed for African violet. To date, the
use of 5S nuclear ribosomal DNA non-transcribed
spacer sequences or internal transcribed spacer
sequences to clearly differentiate Saintpaulia
species in conservation studies (Möller and Cronk
1997, Lindqvist and Albert 1999, 2001) allows
germplasm to be accurately classied, propagated
We are thankful to Ravi R. Sonani and Mafatlal
M. Kher, Sardar Patel University, and Sylvia
DeMar, Managing Editor, American Society for
Horticultural Science, for providing difcult-to-
access literature. We also thank Mafatlal M. Kher
Download Date | 8/4/17 2:48 PM
108 African violet breeding and progress in biotechnological techniques
for some useful suggestions about the review
structure in an earlier draft.
The authors contributed equally to all aspects of
review development and writing.
CONFLICT OF INTEREST
Authors declare no conict of interest.
Adisorn C., 2004. Lesson operating cytogenetic in
agriculture. Department of Horticulture, Chiang
Mai University, Thailand.
AfkhAmi-sArvestAni r., serek m., WinkelmAnn t.,
2012a. Interspecic crosses within the Streptocarpus
subgenus Streptocarpella and intergeneric crosses
between Streptocarpella and Saintpaulia ionantha
genotypes. Sci. Hortic. 148: 215-222.
AfkhAmi-sArvestAni r., serek m., Winkelm Ann
t., 2012b. Protoplast isolation and culture from
Streptocarpus, followed by fusion with Saintpaulia
ionantha protoplasts. Eur. J. Hortic. Sci. 77: 249-260.
AhlooWAliA B.s., mAluszynski m., 2001. Induced
mutations – a new paradigm in plant breeding.
Euphytica 118: 167-173.
Anonymous., 2002. Saintpaulia self-pollination. African
Violet Mag. 55(6): 39.
Arisumi t., 1967. Dominant gene for anthocyanin in the
leaf-blades of African violets. J. Hered. 58: 259-261.
Arisumi t., 1964. Interspecic hybridization in African
violets. J. Hered. 55: 181-183.
Arisumi t., frAzier l.C., 1968. Cytological and
morphological evidence for the single-cell origin of
vegetatively propagated shoots in thirteen species of
Saintpaulia treated with colchicine. Proc. Am. Soc.
Hortic. Sci. 93: 679-685.
BAAtvik s.t., 19 93. T h e g e nu s Saintpaulia (Gesneriaceae)
100 years: History, taxonomy, ecology, distribution
and conservation. Fragm. Flor. Geobot. Suppl. 2: 97-
BhAskAr An s., smith r.h., finer J.J., 1983. Ribulose
bisphosphate carboxylase activity in anther-derived
plants of Saintpaulia ionantha Wendl. Shag. Plant
Physiol. 73: 639-642.
Bourgis f., guyot r., gherBi h., tAilliez e., AmABile
i., sAlse J., lorieux m., delseny m., ghesquière
A., 2008. Characterization of the major fragrance
gene from an aromatic japonica rice and analysis of
its diversity in Asian cultivated rice. Theor. Appl.
Genet. 117: 353-68.
BroertJes C., 1974. Production of polyploids by the
adventitious bud technique. In: Polyploid and
Induced Mutations in Plant Breeding, International
Atomic Energy Agency, Vienna, PL-503(6): 29-34.
BroertJes C., 1972. Use in plant breeding of acute,
chronic or fractionated doses of X-rays or fast
neutrons as illustrated with leaves of Saintpaulia.
In: Agriculture Research Report-776. Centre for
Agricultural Publishing and Documentation, Pudoc,
BroertJes C., 1971. Dose-fractionation studies and
radiation-induced protection phenomena in African
violet. In: Survival of Food Crops and Livestock in
the Event of a Nuclear War. D.W. Benson and A.H.
Sparrow (eds), Proc. Symp. Brookhaven Natl. Lab.
Upton, 1970, U.S. Atomic Energy Commission, Oak
Ridge, Tennessee: 325-342.
BroertJes C., 1968. Mutation breeding of vegetatively
propagated crops. Proc. 5th Eucarpia Congress,
BroertJes C., vAn hArten A.m., 1988. Applied Mut ation
Breeding for Vegetatively Propagated Crops.
Elsevier, Amsterdam: 345.
CAdiC A., Widehem C., 2001. Breeding goals for new
ornamentals. Acta Hort. 552: 75-86.
CAro s.e., stAmpfle J.m., greene m.J., kotArski
m.A., 2006. Using a chalcone synthase gene to infer
phylogenies in the genus Saintpaulia. Bios 77: 72-76.
ChArlesWorth d., ChArlesWorth B., 1987. Inbreeding
depression and its evolutionary consequences. Ann.
Rev. Ecol. Syst. 18: 237-268.
Chen J., henn y r.J., 2009. Cultural guidelines
for commercial production of African violets
(Saintpaulia ionantha) ENH 1096. Environmental
Horticulture Department, Florida Cooperative
Extension Service, Institute of Food and Agricultural
Sciences, University of Florida, USA: 1-4.
ClAyBerg C.d., 1961. Hybridizing with the African
violet species. African Violet Mag. 15: 105-107.
dAttA s.k., teixeirA dA silvA J.A., 2006. Role of
induced mutagenesis for development of new ower
colour and type in ornamentals. In: Floriculture,
Ornamental and Plant Biotechnology: Advances and
Topical Issues (1st Edn.), Chapter 71, Volume I. J.A.
Teixeira da Silva (ed.), Global Science Books, Ltd.,
Isleworth, UK: 640-645.
deguChi A., ohno s., tAtsuzAWA f., dio m., hosokAWA
m., 2016. Identication of the yellow pigments in
Saintpaulia owers. Hort. Res. 15: 123-128.
dunCAn r.r., 1997. Tissue culture-induced variation
and crop improvement. In: Advances in Agronomy
(Vol. 58). D.L. Sparks (ed.), Academic Press,
eAstWood A., ByteBier B., tye h., tye A., roBertson
A., mAunder m., 1998. The conservation status of
Saintpaulia. Curtis’s Bot. Mag. 15: 49-62.
ehrliCh h., 1956. Cytological studies in Saintpaulia
Wendl. (Gesneriacea) [sic]. Ph.D. thesis. University
of Minnesota, USA.
ehrliCh h., 1958. Cytological studies in Saintpaulia
Wendl. (Gesneriaceae). Am. J. Bot. 45: 177-182.
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 109
espino f.J., vAzquez A.m., 1981. Chromosome numbers
of Saintpaulia ionantha plantlets regenerated from
leaves cultured in vitro with caffeine and colchicine.
Euphytica 30: 847-853.
fArJAdi-shAkiB m., mousAvi A., nAderi r., 2012.
Optimization of chromosomal preparation and
cytological analysis of in vitro cultured African
violet (Saintpaulia ionantha Wendl.). Acta Hort.
gAJ m., gAJ m.d., 1996. The high frequency of
variegated forms after in vitro mutagenesis in
Saintpaulia ionantha Wendl. Acta Soc. Bot. Pol. 65:
geier t., 1983. Induction and selection of mutants in
tissue cultures of Gesneriaceae. Acta Hort. 131: 329-
ghorBAnzAde z., AhmAdABAdi m., 2015. Stable
transformation of the Saintpaulia ionantha by
particle bombardment. Iran J. Biotechnol. 13: 11-16.
goidAniCh g., gArAvini C., 19 5 9. Mo r t a l it à d i Saintpaulia
jonantha [sic] per infestazione di Melodogyne
arenaria Thamesii. Riv. Ortoorofrutticoltura Ital.
griesBACh r.J., 1 9 98 . Flavonoids in Saintpaulia ionantha
expressing the fantasy mutation. Phytochemistry 48:
gruneWAldt J., 1983. In vitro mutagenesis of Saintpaulia
and Pelargonium cultivars. Acta Hort. 131: 339-344.
hArrison C.J., möller m., Cronk q.C.B., 1999.
Evolution and development of oral diversity in
Streptocarpus and Saintpaulia. Ann. Bot. 84: 49-60.
huAng J., zhAng k., shen y., huAng z., li m., tAng
d., et Al., 2009. Identication of a high frequency
transposon induced by tissue culture, nDaiZ,
a member of the hAT family in rice. Genomics 93:
hunter r.s., 1948. Photoelectric color-difference meter.
J. Optical Soc. Amer. 38: 661.
itis –integrAted tAxonomiC informAtion system.
Available online at https://www.itis.gov/; cited on 20
JAin s.m., 1993a. Somaclonal variation in Begonia ×
elatior and Saintpaulia ionantha L. Sci. Hort. 54:
JAin s.m., 1993b. Studies on somaclonal variation in
ornamental plants. Acta Hort. 336: 365-372.
JAin s.m., 1997a. Micropropagation of selected
somaclones of Begonia and Saintpaulia. J. Biosci.
JAin s.m., 1997b. Creation of variability by mutation
and tissue culture for improving plants. Acta Hort.
Jensson l.k., BArrett s.C.h., 2002. Solving the puzzle
of mirror-image owers. Nature 417: 707.
JiAo y., Chen J., JiA h.y., zh Ang k., yAng k., 2014.
Cloning of avonoid-3’5’-hydroxylase gene in
Saintpaulia ionantha and expression analysis of
transgenic Nicotiana tabacum. J. Beijing Univ.
Agric. 29: 11-13.
kAeppler s.m., kAeppler h.f., rhee y., 2000. Epigenetic
aspects of somaclonal variation in plants. Plant Mol.
Biol. 43: 179-188.
kelly J.W., lineBerger r.d., 1981. Thermal neutron
induced changes in Saintpaulia. Environ. Exp. Bot.
kolehmAinen J., korpelAi nen h., mutikAinen p.,
2010. Inbreeding and inbreeding depression in
a threathened endemic plant, the African violet
(Saintpaulia ionantha ssp. grotei), of the East
Usambara Mountains, Tanzania. Afr. J. Ecol. 48:
kolehmAinen J., mutikAinen p., 2006. Reproductive
ecology of three endangered African violet
(Saintpaulia H. Wendl.) species in the East Usambara
Mountains, Tanzania. Afr. J. Ecol. 44: 219-227.
kondo e., nAkAyAmA m., kAmeAri n., tAnikAWA n.,
moritA y., AkitA y., hAse y., tAnAkA A., ishizAkA
h., 2009. Red-purple ower due to delphinidin
3,5-diglucoside, a novel pigment for Cyclamen spp.,
generated by ion-beam irradiation. Plant Biotechnol.
krishnA h., AlizAdeh m., singh d., singh u., ChAuhAn
n., eftekhAri m., sAdh r.h., 2016. Somaclonal
variations and their applications in horticultural
crops improvement. 3 Biotech. 6(1): 54.
kushikAWA s., hoshino y., mii m., 2001. Agrobacterium-
mediated transformation of Saintpaulia ionantha
Wendl. Plant Sci. 161: 953-960.
kushikAWA s., miyoshi k., mii m., 2002. Pre-culture
treatment enhances transient GUS gene expression
in leaf segment of Saintpaulia ionantha Wendl. after
inoculation with Agrobacterium tumefaciens. Plant
Biotechnol. 19: 149-152.
lArkin p.J., sCoWCroft W.r., 1981. Somaclonal variation
– a novel source of variability from cell cultures for
plant improvement. Theor. Appl. Genet. 60: 197-214.
lindqvist C., AlBert v.A., 1999. Phylogeny and
conservation of African violets (Saintpaulia;
Gesneriaceae): New ndings based on nuclear
ribosomal 5S non-transcribed spacer sequences.
Kew Bull. 54: 363-377.
lindqvist C., AlBert v.A., 2001. A high elevation
ancestry for the Usambara Mountains and lowland
populations of African violets (Saintpaulia,
Gesneriaceae). Syst. Geogr. Plants 71: 37-44.
lineBerger r.d., druCkenBrod m., 1985. Chimeral
nature of the pinwheel owering African violets
(Saintpaulia, Gesneriaceae). Am. J. Bot. 72: 1204-
Loureiro J., rodriguez e., doLežeL J., SantoS C., 2007.
Two new nuclear isolation buffers for plant DNA
ow cytometry: a test with 37 species. Ann. Bot.
mAtsudA s., sAto m., ohno s., yAng s.J., doi m.,
hosokAWA J., 2014. Cutting leaves and plant growth
Download Date | 8/4/17 2:48 PM
110 African violet breeding and progress in biotechnological techniques
regulator application enhance somaclonal variation
induced by transposition of VGs1 of Saintpaulia.
J. Jpn. Soc. Hortic. Sci. 83: 308-316.
merCuri A., de Benedetti l., BurChi g., sChivA t.,
2000. Agrobacterium-mediated transformation of
African violet. Plant Cell Tiss. Org. Cult. 60: 39-46.
möller m., Cronk q.C.B., 1997. Phylogeny and
disjunct distribution: evolution of Saintpaulia
(Gesneriaceae). Proc. Royal Soc. London B: Biol.
Sci. 264: 1827-1836.
nishihArA m., shimodA t., nAkAtsukA t., ArimurA
g. 2013. Frontiers of torenia research: innovative
ornamental traits and study of ecological interaction
networks through genetic engineering. Plant
Methods 9: 23.
ohki s., hAshimoto y., ohno m., 2009. Preliminary
report on Agrobacterium-mediated genetic
transformation of Begonia rex and Saintpaulia spp.
Acta Hort. 829: 345-348.
ono e., fukuChi-mizutAni m., nAkAmurA n., fukui
y., yonekurA-sAkAkiBAr A k., yAmAguChi m.,
nAkAyAmA t., tAnAkA t., kusumi t., tAnAkA y.,
2006. Yellow owers generated by expression of the
aurone biosynthetic pathway. Proc. Nat. Acad. Sci.
USA 103: 11075-11080.
pAek k.y., hAhn e.J., 1999. Variations in African violet
‘Crimson Frost’ micropropagated by homogenized
leaf tissue culture. HortTechnology 9: 625-629.
pei r.J., Chen x.q., su n n., zhAng n.n., liu y., liu
f.h., 2012. Petal cell pH value determination and
F3’5’ H gene fragment cloning of Saintpaulia
ionantha. J. Tianjin Agri. Univ. 19: 11-14.
rAm m.s.n., mohAndAs s., 2003. Transformation
of African violet (Saintpaulia ionantha) with
glucanase-chitinase genes using Agrobacterium
tumefaciens. Acta Hort. 624: 471-478.
sAhiJrAm l., 2014. Modifying DNA methylation pattern
in embryos for application in horticultural crop
improvement. In: Horticulture for Inclusive Growth,
Westville Publishing House, New Delhi: 504-521.
sAhiJrAm l., 2015. Somaclonal variation in
micropropagated plants. In: Plant Biology and
Biotechnology (Vol. II) Plant Genomics and
Biotechnology. B. Bahadur, M.V. Rajam, L.
Sahijram, K.V. Krishnamurthy (eds), Springer,
Heidelberg, Germany: 407-416.
sAmAntA m.k., dey A., gAyen s., 2016. CRISP/Cas9: an
advanced tool for editing plant genomes. Transgenic
Res. 25: 561-573.
sAto m., hosokAWA m., doi m. 2011a. Somaclonal
variation is induced de novo via the tissue culture
process: A study quantifying mutated cells in
Saintapulia. PLoS ONE 6: e23541.
sAto m., kAWABe t., hosokAWA m., tAtsuzAWA f., doi m.,
2011b. Tissue culture-induced ower-color changes
in Saintpaulia caused by excision of the transposon
inserted in the avonoid 3’, 5’ hydroxylase (F3 ’5’H )
promoter. Plant Cell Rep. 30: 929-939.
senevirAtne k.A.C.n, WiJesundArA d.s.A., 2003. New
African violets (Saintpaulia ionantha H. Wendl.)
induced by colchicine. Curr. Sci. 87: 138-140.
senevirAtne k.A.C.n., WiJesundArA d.s.A., 2007. First
African violets (Saintpaulia ionantha H. Wendl.)
with a changing colour pattern induced by mutation.
Am. J. Plant Physiol. 2: 233-236.
shAJiee k., tehrAnifAr A., nAderi r., khAlighi A.,
2006. Somaclonal variation induced de novo leaf
chimeric mutants during in vitro propagation of
African violet (Saintpaulia ionantha Wendl.). Acta
Hort. 725: 337-340.
skog l.e., BoggAn J.k., 2010. World checklist of
Gesneriaceae. Washington, DC: Dept. of Botany,
spArroW A.h., spArroW r.C., sChAirer l.A., 1960.
The use of X-rays to induce somatic mutations in
Saintpaulia. African Violet Mag. 13: 32-37.
steWArt d., grACiet e., Wellmer f., 2016. Molecular
and regulatory mechanisms controlling oral organ
development. FEBS J. 283: 1823-1830.
sugiurA t., 1936. Studies on the chromosome numbers in
higher plants, with special reference to cytokinesis.
Cytologia (Tokyo) 7: 544-595.
sun y.J., Chen x.q., sun n., Chen J., zhAng l.,
2010. Karyotype analysis of Saintpaulia ionantha.
J. Tianjin Agri. Univ. 17: 5-8.
tAtsuzAWA f., hosokAWA m., 2016. Flower colors
and their anthocyanins in Saintpaulia cultivars
(Gesneriaceae). Hort. J. 85: 63-69.
tAtsuzAWA f., hosokAWA m., sAito n., hondA t., 2012.
Three acylated anthocyanins and a avone glycoside
in violet-blue owers of Saintpaulia ‘Thamires’.
S. Afr. J. Bot. 79: 71-76.
teixeirA dA silvA J.A., BoliBok h., rAkoCzy-
troJAnoWskA m., 2007. Molecular markers in
micropropagation, tissue culture and in vitro plant
research. Genes, Genomes Genomics 1(1): 66-72.
teixeirA dA silvA J.A., deWir y.h., WiCAksono A.,
kher m.m., kim h.h., hosokAWA m., zeng s.,
2016a. Morphogenesis and developmental biology
of African violet (Saintpaulia ionantha H. Wendl).
J. Plant Dev. 23: 15-25.
teixeirA dA silvA J.A., doBránszki J., CArdoso J.C.,
ChAndler s.f., zeng s.J., 2016 b. Review: Methods
for genetic transformation in Dendrobium. Plant
Cell Rep. 35: 483-504.
teixeirA dA silvA J.A., zeng s.J., WiCAksono A., kher
m.m., kim h.-h., hosokAWA m., deWir y.s., 2017.
In vitro propagation of African violet: a review. S.
Afr. J. Bot. (in press) DOI: 10.1016/j.sajb.2017.05.018
the plAnt list, 2017. Saintpaulia. Available online at:
paulia; cited on 20 May 2017.
tsukAmoto y., mAekAWA s., yAmAmoto k., sAsAki m.,
1982. Saintpaulia. Bunka Publishing, Tokyo, Japan.
Download Date | 8/4/17 2:48 PM
J.A. Teixeira da Silva, Y.H. Dewir, A. Wicaksono, L. Sahijram, H. Kim, S. Zeng, S.F. Chandler, M. Hosokawa 111
vAn hArten A.m., 2007. Mutation Breeding: Theory
and Practical Applications. Cambridge University
Press, Cambridge, UK: 368.
vAn sChAik n.W., neWlAnds g., 1963. The problem of
breeding a red African violet. S. Afr. J. Sci. 59: 55-
vA zquez A.m., dAvey m.r., short k.C., 1977.
Organogenesis in culture of Saintpaulia ionantha.
Acta Hort. 78: 249-258.
vogel s., 1978. Evolutionary shifts from reward to
deception in pollen owers. In: The Pollination of
Flowers by Insects. A. Richards (ed.), Linn. Soc.
Sym. Ser., Academic Press, London: 89-96.
WAng l., gAo q., WAng y.z., lin q.B., 2006. Isolation
and sequence analysis of two CYC-like genes,
SiCYC1A and SiCYC1B, from zygomorphic and
actinomorphic cultivars of Saintpaulia ionantha
(Gesneriaceae). Acta Phytotax. Sin. 44: 353-361.
WArfield d., 1973. Induction of mutations in African
violet (Saintpaulia ionantha Wendl.) by ethyl-
methanesulfonate. HortScience 8: 29.
WinkelmAnn t., gruneWAldt J., 1995. Analysis of
protoplast-derived plants of Saintpaulia ionantha H
Wen d l. Plant Breeding 114: 346-350.
WongpiyAsAtid A., Jompuk p., ChusreeAeom k.,
tAyChAsinpitAk t., 2007a. Effects of chronic gamma
irradiation on adventitious plantlet formation of
Saintpaulia ionantha (African violet) detached
leaves. Kasetsart J. Nat. Sci. 41: 414-419.
WongpiyAsAtid A., thin nok t., tAyChAsinpitAk t.,
Jompuk p., ChusreeAeom k., lAmseeJAn s., 2007b.
Effects of acute gamma irradiation on adventitious
plantlet regeneration and mutation from leaf cuttings
of African violet (Saintpaulia ionantha). Kasetsart J.
Nat. Sci. 41: 633-640.
yAng s.J., hosokAWA m., hAyAshi t., yAzAWA s., 2003.
Wounding enhances rapid-browning responsiveness
of distal unwounded leaves to water stimulus in
Ruellia macrantha. J. Jpn. Soc. Hort. Sci. 72: 286-
yAng s.J., hosokAWA m., hAyAshi t., yAzAWA s., 2002.
Leaf browning induced at sites distant from wounds
in Acanthaceae and Gesneriaceae plants. J. Jpn. Soc.
Hort. Sci. 71: 535-537.
yAng s.J., hosokAWA m., mizutA y., yun J.g., mAno J.,
yAzAWA s., 2001. Antioxidant capacity is correlated
with susceptibility to leaf spot caused by a rapid
temperature drop in Saintpaulia (African violet).
Sci. Hort. 88: 59-69.
yAng s.J., kitAmur A y., hosokAWA m., yAzAWA s.,
2006. Low temperature sensitivity enhanced by
local wounding in Saintpaulia. J. Jpn. Soc. Hortic.
Sci. 75: 476-480.
ye z.q., li J.h., WAng g.d., 2014. Agrobacterium-
mediated genetic transformation of AtTIP5;1 gene
into Saintpaulia ionantha. Acta Bot. Occident. Sin.
34: 2412 -2417.
yu W., yAu y.y., BirChler J.A., 2016. Plant articial
chromsome technology and its potential application
in genetic engineering. Plant Biotech. J. 14: 1175-
yun J.g., hAyAshi t., yAzAWA s., 1997. Diurnal changes
in leaf spot sensitivity of Saintpaulia (A f rican
violet). Sci. Hortic. 70: 179-186.
zhou l.B., li W.J., mA s., dong x.C., yu l.x., li q.,
zhou g.m., gAo q.x., 2006a. Effects of ion beam
irradiation on adventitious shoot regeneration from
in vitro leaf explants of Saintpaulia ionahta [sic].
Nucl Instr. Methods Phys. Res. Sect. B 244: 349-353.
zhou l.B., li W.J., mA s., dong x.C., li q., gAo
q.x., 2006b. Effects of X-ray and electron beam
irradiation on adventitious bud regeneration from
in vitro leaf explants of Saintpaulia ionahta [sic].
J. Radiat. Res. Radiat. Process 24: 53-58.
Received January 13, 2017; accepted May 23, 2017
Download Date | 8/4/17 2:48 PM