Analysis of CDF in potato. A presentation on the Research paper by kloostermann et al.

1. Naturally occurring allele
diversity allows potato
cultivation in northern
latitudes, 2013
BJORN KLOOSTERMAN, JOSE ´ A. ABELENDA, MARI ´A DEL MAR CARRETERO GOMEZ1, MARIAN OORTWIJN,
JAN M. DE BOER, KRISSANA KOWITWANICH, BEATRIX M. HORVATH, HERMAN J. VAN ECK, CEZARY
SMACZNIAK, SALOME ´ PRAT, RICHARD G. F. VISSER & CHRISTIAN W. B. BACHEM
doi:10.1038/nature11912
Presented by: Jeny Jose
Agricultural Biotechnology
4th Semester

3. Potato
 Potato ( S o l a n u m t u b e r o s u m L.) originates from
the Andes.
 It has evolved as a short-day-dependent tuber formation as
a vegetative propagation strategy.
 Potato is a member of the Solanaceae family and is one of
the world’s most important food crops
 Potato develops tubers from underground stems called
stolons. Its equatorial origin makes potato essentially short-
day dependent for tuberization and potato will not make
tubers in the long-day conditions of spring and summer in
the northern latitudes.
 Thus, one of the first selected traits in potato leading to a
European potato type is likely to have been long-day
acclimation for tuberization.
 The potato plant maturity phenotype is observed as a
major-effect quantitative trait locus (QTL) that maps to
chromosome 5

4. The central idea of the
publication is the identification
of a central regulator
underlying a major-effect
quantitative trait locus for plant
maturity and initiation of tuber
development.

5. Flowering Pathway

6. Tuberization

7. Experimental setup
 Plant maturity trait serves as a measure of onset of leaf senescence and
total length of the plant life cycle, as well as the associated time point of
tuberization and ultimately potato yield.
 We used two diploid potato populations, derived from wild and
domesticated genotypes (generated from the parental crosses C*E and
SH*RH)
 An additional set of nearly 2,000 individual siblings of the cross were
generated and screened with existing genetic markers to identify
recombination locations in this genetic region. Subsequent phenotyping
and fine mapping allowed them to narrow down the locus responsible for
this trait to a region of around 110 kilobases

8. Candidate gene
 A CDF homologue (PGSC003DMG400018408) on chromosome 5, hereafter
referred to as StCDF1 (Solanum tuberosum CDF gene 1), was chosen as a
candidate gene for the plant maturity phenotype based on its regulatory links
with the StCO and StSP6A genes that have an established role in tuberization.
 Sequence analysis of the StCDF1 gene in the very late-maturing C*E
descendant CE3027 showed homozygosity for an StCDF1allele denoted
StCDF1.1 whereas the very early maturing descendant CE3130 has two
different truncated alleles (denoted StCDF1.2 and StCDF1.3)
 In StCDF1.2,an insertion results in a frame-shift introducing a premature stop
codon (7-base-pair (bp) insertion
 Whereas in StCDF1.3 there is a larger insertion(865bp) that leads to a fusion
protein with 22 additional amino acids, replacing the 52 carboxy-terminal
residues found in the StCDF1.1 protein

9. Experiment
 The early maturing/tuberizing StCDF1.2 gene variant,under control of the cauliflower
mosaic virus 35S promoter (CaMV 35S), was introduced into the short-day-dependent S.
tuberosum group andigenum (referred to here as S. andigenum) genotype 21 and into
the very late maturing CE3027 descendant.
 Under Long day Conditions the transformed lines tuberize at the same time as the
earliest C*E genotypes (CE3130).
 Overexpression of the StCDF1.2 allele thus phenocopies the early tuberization, shoot
architecture and maturation traits of early genotypes
 In addition to the DOF domain, CDF proteins share three conserved basic domains in
their C terminus , which were reported to be important for protein–protein interaction
 Loss of the C-terminal end in the StCDF1.2 and StCDF1.3 alleles may impair interaction
of these truncated proteins with the FKF1–GI complex, thus leading to accumulation of
these repressors and the observed effects on tuberization onset.

10. Potato
 In potato, two CONSTANS genes StCO1and StCO2 was shown to repress
tuber formation in long days16
 Both genes are transcriptionally repressed in the transgenic S.andigenum
lines harbouring the35S::StCDF1.2 transgene under long-day conditions
indicating a conserved repressive function of potato StCDF1on StCO1/2.
 The StCO is involved in StSP5G activation in long days. This FT homologue
appears to function as a suppressor of StSP6A gene expression, repression
of StCO1/2 expression by StCDF1 indirectly induces StSP6A expression by
downregulating theStSP5Ggene