LIBRO-CONGRESO-CITRUS

S03P06
Ploidy and gene expression in clementine
Niñoles R., Aleza P., Castillo M.C., Navarro L., and Ancillo G.
Instituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Protección Vegetal y Biotecnología, Spain. ancillo@ivia.es
Polyploidy has long been recognized as an important force in the evolution of flowering plants as often results
in novel phenotypes that are not present in their diploid progenitors or exceed the range of the contributing
species. The new acquired phenotypes may have an advantage in adaptation that may also enhance their
interest for agriculture. Many crops, including citrus, are bred to a higher level of ploidy in search of desirable
traits. In previous works of our group, synthetic clementines with different levels of ploidy were generated,
specifically haploid, dihaploid and autotetraploid lines were obtained. This plant material represents a valuable
tool for studying the effects of polyploidization at a molecular level since important traits are expressed in
a different manner. Interestingly, dihaploid lines have been not able to flower, while haploid, diploid and
autotetraploid lines have. By using a microarray approach, we have accomplished a comprehensive analysis
of transcriptome divergence among the newly created clementine lineages with different genome dosage
and specifically have explored new gene expression patterns related to the ability to flower. Differences in
expression in the bark tissue of the four lineages were found significant for ninety four genes. Clustering
analysis results and expression profile of these genes in the 4 compared lineages were used as additional
criteria to select 16 genes putatively involved in the flowering differences found in the lineages. To explore
their potential involvement in the flowering event we have analyzed their expression in floral organs and
the occurrence of differential expression in juvenile and adult bark tissues. Results and discussion will be
presented.
S03P07
Expression of flowering genes in different shoot types in citrus
Muñoz-Fambuena N. 1 , Mesejo C. 1 , González-Mas M.C. 2 , Iglesias D.J. 2 , Primo-Millo E. 2 , and Agustí M. 1
1 Universitat Politècnica de València (UPV), Instituto Agroforestal Mediterráneo, Spain; and 2 Instituto Valenciano de Investigaciones
Agrarias (IVIA), Centro de Citricultura y Producción Vegetal, Spain. namuofam@upvnet.upv.es
In citrus, three main shoot types can be distinguished: vegetative shoots (VS), leafy inflorescences (LY)
and leafless inflorescences (LS). This study aimed to determine the relationship between flowering genes
expression and shoot type. To this end, shoots of ‘Moncada’ mandarin were collected at the beginning of
bud sprouting, and-flowering genes expression was analysed by RT-PCR. LS and LY did not-significantly differ
in the number of flowers per inflorescence. However, they significantly differed in flowering genes relativeexpression.
Thus, LS presented the highest relative expression of the-flowering genes CiFT, CsAP1, CsLFY,
CiSEP1 and CiSEP3, and the lowest of that flowering inhibitor CsTFL, whereas VS showed the opposite. LY
showed intermediate relative expression between VS and LS of either flowering promoters or inhibitor.
Results indicate an absence of relationship between the number of flowers per inflorescence and relative
gene expression. On the other hand, the different levels of expression of flowering genes, CiFT, floweringtime,
CsTFL, CsLFY, CsAP1, meristem identity and CiSEP1 and CiSEP3, floral organ specification, seem to be
related with the-appearance of different shoot types.
S03P08
Shortening the juvenile phase in Arabidopsis plants by ectopic expression of citrus transcription
factors
Castillo M.C., Navarro L., and Ancillo G.
Instituto Valenciano de Investigaciones Agrarias (IVIA), Centro de Protección Vegetal y Biotecnología, Spain. ancillo@ivia.es
In citrus, juvenility is a long period (5-20 years depending on the variety) during which floral initiation does not
occur even under normally inductive environmental conditions. Efficient breeding is limited due to this long
period of juvenility. Several transcription factors (TFs) were identified as differentially expressed in juvenile
and adult phases in an approach involving the use of a microarray containing 1152 putative unigenes of citrus
XII INTERNATIONAL CITRUS CONGRESS 2012 - 67
S03