Characterizing the involvement of FaMADS9 in the regulation of strawberry fruit receptacle development

Authors: VALLARINO, JOSE - University Of Malaga; MERCHANTE, CATHARINA - University Of Malaga; SANCHEZ, SEVILA - University Of Malaga; BALAGUER, MARIA - North Carolina State University; POTT, DELPHINE - University Of Malaga; ARIZA, MARIA - University Of Malaga; CASANAL, ANA - University Of Malaga; POSE, DAVID - University Of Malaga; VIOQUE, AMALIA - University Of Malaga; AMAY, IRAIDA - University Of Malaga; WILMITZER, LOTHAR - Max Planck Institute Of Molecular Plant Physiology; SOLANO, ROBERTO - Centro De Investigacions Biologicas, Cib, (CSIC); SOZZANI, ROSANGELA - North Carolina State University; FERNIE, ALISDAIR - Max Planck Institute Of Molecular Plant Physiology; BOTELLA, MIGUEL - University Of Malaga; Giovannoni, James; VALPUESTA, VICTORIANO - University Of Malaga; OSORIO, SONIA - University Of Malaga

Submitted to: Plant Biotechnology Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2019
Publication Date: 4/1/2020
Citation: Vallarino, J., Merchante, C., Sanchez, S.J., Balaguer, M., Pott, D., Ariza, M., Casanal, A., Pose, D., Vioque, A., Amay, I., Wilmitzer, L., Solano, R., Sozzani, R., Fernie, A., Botella, M., Giovannoni, J.J., Valpuesta, V., Osorio, S. 2020. Characterizing the involvement of FaMADS9 in the regulation of strawberry fruit receptacle development. Plant Biotechnology Journal. 18:929-943. https://doi.org/10.1111/pbi.13257.
DOI: https://doi.org/10.1111/pbi.13257

Interpretive Summary: Studies regarding the regulatory genes of the strawberry fruit ripening process are limited, and most of the studies have examined the roles of these genes in the metabolic changes that occur with ripening. In better studied fruit such as tomato, the RIN transcription factor has been linked to ripening control. Here we characterized the closest strawberry gene relative to the tomato RIN gene, termed FaMADS9. We repressed this gene in strawberry via RNAi gene repression and characterized the effects. Our data support a major role of the FaMADS9 gene in not only the orchestration of the metabolic changes that occur during fruit ripening, but also the possible involvement of plant hormones in the fruit developmental program, and, in particular, in the formation and synthesis of the external fruit cuticle.

Technical Abstract: FaMADS9 is the strawberry gene that exhibits the highest homology to the tomato RIN gene. Transgenic lines were obtained in which FaMADS9 was silenced. The fruits of these lines did not show differences in basic parameters, such as fruit firmness or colour, but exhibited lower Brix values in three of the four independent lines. Metabolomic analysis of the receptacles of the transformed fruits identified significant changes in the content of maltose, galactonic acid-1,4-lactone, proantho- cyanidins and flavonols at the green/white stage, while isomaltose, anthocyanins and cuticular wax metabolism were the most affected at the red stage. Among the regulatory genes that were differentially expressed in the transgenic receptacles were several genes previously linked to flavonoid metabolism, such as MYB10, DIV, ZFN1, ZFN2, GT2, and GT5, or associated with the action of hormones, such as abscisic acid, SHP, ASR, GTE7 and SnRK2.7. The inference of a gene regulatory network, based on a dynamic Bayesian approach, among the genes differentially expressed in the transgenic receptacles at the white and red stages, identified the genes KAN1, DIV, ZFN2 and GTE7 as putative targets of FaMADS9. A MADS9-specific CArG box was identified in the promoters of these genes.