title: Heterologous expression of Arabidopsis ABF4 gene in potato enhances tuberization through ABA-GA crosstalk regulation.
abstract: Potato (Solanum tuberosum L.) tuberization is regulated by many signals, such as abscisic acid (ABA), sucrose and gibberellic acid (GA). ABA and sucrose are positive modulators, while GA is an inhibitor of the process. ABF (ABRE-binding factor) proteins are transcription factors involved in ABA and stress signaling. Previously, we reported that S. tuberosum StABF1 could mediate the ABA effects on tuberization. The aim of the present study was to evaluate the potential use of ABF genes to enhance tuberization and to determine the molecular mechanism involved. For this purpose, transgenic potato plants expressing the Arabidopsis ABF4 or ABF2 genes were generated, and their tuberization capacity and response to tuberization-related signals were analyzed in vitro. The results indicate that both ABF4 and ABF2 proteins positively regulate potato tuber induction; however, only ABF4 expression significantly increases the number and weight of the tubers obtained, without stunting growth. ABF4 and ABF2 transgenic plants exhibit ABA hypersensitivity during tuberization, accompanied by a GA-deficient phenotype. ABF4 expression triggers a significant rise in ABA levels in stolons under tuber-inducing conditions as compared with wild-type plants and a transcriptional deregulation of GA metabolism genes. Our results demonstrate that Arabidopsis ABF4 functions in potato ABA-GA signaling crosstalk during tuberization by regulating the expression of ABA- and GA-metabolism genes. ABF4 gene might be a potential tool to increase tuber production, since its heterologous expression in potato enhances tuber induction without affecting plant growth.
authors.affiliation: Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor Torres", Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Vuelta de Obligado 2490 2º piso, C1428ADN, Buenos Aires, Argentina.
authors.forename: María Noelia
authors.initials: MN
authors.lastname: Muñiz García
authors.forename: Margarita
authors.initials: M
authors.lastname: Stritzler
authors.forename: Daniela Andrea
authors.initials: DA
authors.lastname: Capiati
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005875:Gibberellins / Q000378:metabolism; D035281:Plant Tubers / Q000254:growth & development*; D030821:Plants, Genetically Modified / Q000502:physiology; D020239:Receptor Cross-Talk; D011198:Solanum tuberosum / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D004268:DNA-Binding Proteins; D005875:Gibberellins; D014157:Transcription Factors; C576624:AREB2 protein, Arabidopsis; C007842:gibberellic acid; C508877:At1g45249 protein, Arabidopsis