Molecular investigations of the somatic embryogenesis recalcitrance in the cherry (Prunus cerasus L.) rootstock CAB 6P

Authors: KAOUTHER BEN MAHMOUD, EMNA JEDIDI, FABIENNE DELPORTE, YORDAN MUHOVSKI, AHMED JEMMALI, PHILIPPE DRUART

Abstract: Somatic embryogenesis is a powerful tool for clonal propagation and plant breeding in many plant species, but its application is limited by the genotype response based on the interaction between gene expression and culture conditions. In this context, the recalcitrance of the nonembryogenic cherry rootstock Prunus cerasus cultivar CAB 6P was investigated via the analysis of the candidate genes PiABP19, Picdc2, and PiSERK3 in comparison with the embryogenic genotype Prunus incisa cultivar N°131. Semiquantitative RT-PCR was employed to assess the transcript level of these genes in leaf explants and derived calli of the two genotypes cultured on picloram-containing MS medium during 30 days of culture. Results showed that only Picdc2 and PiSERK3 gave differential expression profiles between genotypes N°131 and CAB 6P. Concerning N°131, transcripts levels were low at the beginning of culture and then increased to reach peaks at the 15th (PiSERK3) and at the 25th (Picdc2 and PiSERK3) days of culture. Contrarily, with the CAB 6P cultivar, transcripts levels that were high at the beginning of the culture considerably decreased afterwards. This decrease may explain the recalcitrance of the cultivar CAB 6P to somatic embryogenesis, at least in our experimental conditions.

Keywords: Somatic embryogenesis, recalcitrance, RT-PCR, gene expression, leaf explants, Prunus

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