MOLECULAR GENETIC INVESTIGATION OF MALFORMED FLOWER TYPES OF ROSA HYBRID L.

To clarify the molecular mechanism of flower development in Rosa hybrid L. different MADS-box-genes were investigated in normally developed flowers and in malformed flowers (similar C-function mutation). Expression levels of all A, B and C class genes were examined by qRT-PCR in different flower organs of both types of flowers.
Expression patterns of MADS-box genes in early organ development were investigated by in-situ RT-PCR. Three different unknown APETALA1 homologous cDNA’s were isolated and designated as RhAP1-1, RhAP1-2 and RhFUL. Exclusive expression of APETALA1 homologue genes RhAP1-1 and RhAP1-2 in whorl 1 and 2 of rose flowers demonstrate that the expression patterns are similar to APETALA1 homologue genes in other plant species.
In contrast, RhFUL showed a unique expression pattern and was expressed only in sepals.
Comparison of expression patterns between normal and malformed flowers demonstrated that two different B class genes were unaffected.
All A class genes were up regulated and two C class genes were down regulated in all flower organs.
Suppression of the C class genes RhC1 and RhC2 may be the reason for expression of RhAP1-1, RhAP1-2 and RhFUL in whorls 3 and 4 that lead to the malformed flower phenotype.
Possible reasons for suppression of class C genes in early bud stages are discussed.

XXIV International Eucarpia Symposium Section Ornamentals: Ornamental Breeding Worldwide

H. Mibus, A. Jedrzejuk, M. Serek

APETALA1, class A, flower development, MADS-box, Rosa × hybrida

https://doi.org/10.17660/ActaHortic.2012.953.36