© Benaki Phytopathological Institute
Molecular Biotechnology on agricultural crop improvement
47
time (Chardon
et al.,
2004) and drought tol-
erance in maize (Hao
et al.,
2010). A meta-
analysis of QTL associated with plant digest-
ibility and cell wall composition in maize has
been carried out and fifteen meta QTL with
confidence interval (CI) smaller than 10cM
were identified (Truntzler
et al.,
2010).
Potato (Solanum tuberosum, L.,
Solanaceae)
Cultivated potato is the world’s third
most important human food crop (www.
cipotato.org). It is also used as raw materi-
al for starch and alcohol production (Can-
tos-Lopes
et al.,
2018). The basic chromo-
some number for potato species is 12. Even
though one of the most widespread food
crop around the world, the genetics of many
potato traits is poorly understood.
Insights in genomic properties
An ultrahigh-density (UHD) genetic map
composed of approximately 10,000 Ampli-
fied Fragment Length Polymorphism (AFLP)
markers has been developed, which is most
likely the densest map for a plant species
ever constructed (Van Os
et al.,
2006). Re-
cently, the relationship between the ge-
netic and chromosome map in potato was
displayed and two linkage maps were inte-
grated with potato genome sequence de-
veloping 8303 Single Nucleotide Polymor-
phism (SNP) for genome-guided breeding
(Felcher
et al.,
2012). Moreover, (Sharma
et
al.,
2013) elaborated 2469 marker loci in
a linkage map which was integrated with
potato reference genome (DM) and other
physical and genetic maps of potato pro-
viding detailed information about chromo-
somal gene distribution. Using RFLP and
AFLP markers, a QTL and linkage map of
two segregating diploid populations previ-
ously evaluated for sugar content after cold
storage, was generated. Ten potato genes
with unknown function in carbon metabo-
lism or transport were mapped and tested
for their effects on sugar content. Results
displayed linkage between glucose, fruc-
tose and sucrose QTLs and all of eight can-
didate gene loci (AGPaseS, AGPaseB, SbeI,
GapC, Invap, Ppa1, Sut1, Sut2) (Menéndez
et al.,
2002). Several QTLs affecting the abil-
ity to form tubers under long photoperiods
(earliness) have been identified (
Š
imko
et al.,
1999). A functional map for pathogen resis-
tance, enriched with RGA (resistance gene
analog) and DRL (defence related locus) se-
quences, SNPs and insertion-deletion poly-
morphisms (InDels) tightly linked or locat-
ed within Nucleotide Binding Site - Leucine
Rich Repeat (NBS-LRR) -like genes, has been
developed on the basis of two potato pop-
ulations (BC9162 and F1840) (Rickert
et al.,
2003; Trognitz
et al.,
2002). Recently, twen-
ty-one QTL and eight reference published
potato maps were merged together and
the first consensus map was built. Individual
QTLs for resistance to the late blight patho-
gen,
Phytophthora infestans
(Mont.) de Bary,
and maturity traits were projected onto the
consensus map and the first meta-analysis
performed deals with both development
trait and resistance to a biotic stress in pota-
to (Danan
et al.,
2011).
As a major follow-up, the genome of po-
tato (850 Mb) was sequenced by the inter-
national Potato Genome Sequencing Con-
sortium (PGSC), which was comprised by 13
countries [
].
The new genome sequence data provides
information about extensive copy number
variation (CNV) which has great impact on
219.8 Mb (30.2%) of the potato genome. Al-
most 30% of genes are subjected to at least
partial duplication or deletion which reveals
the highly heterogeneous nature of the po-
tato genome (Hardigan
et al.,
2016). Com-
parative sequence analysis of
Solanum
and
Arabidopsis
in a hot spot for pathogen re-
sistance on potato chromosome V has also
been performed and revealed a patchwork
of conserved and rapidly evolving genome
segments (Ballvora
et al.,
2007).
Several efforts to generate EST resources
for potato have been performed (Flinn
et al.,
2005). Potato cDNA microarray analysis was
performed to assess the potential of tran-
scriptomics to detect differences in gene ex-
pression due to genetic differences or envi-
ronmental conditions (van Dijk
et al.,
2009). A
