ASPECTOS BASICOS DEL METABOLISMO DEL ALMIDON Y APLICACIONES BIOTECNOLOGICAS

BIO2013-49125-C2-2-P

Nombre agencia financiadora Ministerio de Economía y Competitividad
Acrónimo agencia financiadora MINECO
Programa Programa Estatal de Fomento de la Investigación Científica y Técnica de Excelencia
Subprograma Subprograma Estatal de Generación del Conocimiento
Convocatoria Proyectos de I+D dentro del Subprograma Estatal de Generación del Conocimiento (2013)
Año convocatoria 2013
Unidad de gestión Dirección General de Investigación Científica y Técnica
Centro beneficiario UNIVERSIDAD PÚBLICA DE NAVARRA (UPNA)
Centro realización INSTITUTO DE AGROBIOTECNOLOGÍA Y RECURSOS NATURALES (IARN)
Identificador persistente http://dx.doi.org/10.13039/501100003329

Publicaciones

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Mitochondrial Zea mays Brittle1-1 Is a Major Determinant of the Metabolic Fate of Incoming Sucrose and Mitochondrial Function in Developing Maize Endosperms

RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia
  • Bahaji, Abdellatif
  • Muñoz, Francisco José
  • Seguí-Simarro, Jose M.|||0000-0001-7672-4169
  • Camacho-Fernández, Carolina|||0000-0003-0483-8065
  • Rivas-Sendra, Alba|||0000-0003-4300-2295
  • Parra Vega, Verónica
  • Ovecka, Miroslav
  • Li, Jun
  • Sánchez-López, Ángela María
  • Almagro, Goizeder
  • Baroja-Fernández, Edurne
  • POZUETA-ROMERO, JAVIER
[EN] Zea mays Brittle1-1 (ZmBT1-1) is an essential component of the starch biosynthetic machinery in maize endosperms, enabling ADPglucose transport from cytosol to amyloplast in exchange for AMP or ADP. Although ZmBT1-1 has been long considered to be an amyloplast-specific marker, evidence has been provided that ZmBT1-1 is dually localized to plastids and mitochondria (Bahaji et al., 2011b). The mitochondrial localization of ZmBT1-1 suggested that this protein may have as-yet unidentified function(s). To understand the mitochondrial ZmBT1-1 function(s), we produced and characterized transgenic Zmbt1-1 plants expressing ZmBT1-1 delivered specifically to mitochondria. Metabolic and differential proteomic analyses showed down-regulation of sucrose synthase (SuSy)-mediated channeling of sucrose into starch metabolism, and up-regulation of the conversion of sucrose breakdown products generated by cell wall invertase (CWI) into ethanol and alanine, in Zmbt1-1 endosperms compared to wild-type. Electron microscopic analyses of Zmbt1-1 endosperm cells showed gross alterations in the mitochondrial ultrastructure. Notably, the protein expression pattern, metabolic profile, and aberrant mitochondrial ultrastructure of Zmbt1-1 endosperms were rescued by delivering ZmBT1-1 specifically to mitochondria. Results presented here provide evidence that the reduced starch content in Zmbt1-1 endosperms is at least partly due to (i) mitochondrial dysfunction, (ii) enhanced CWI-mediated channeling of sucrose into ethanol and alanine metabolism, and (iii) reduced SuSy-mediated channeling of sucrose into starch metabolism due to the lack of mitochondrial ZmBT1-1. Our results also strongly indicate that (a) mitochondrial ZmBT1-1 is an important determinant of the metabolic fate of sucrose entering the endosperm cells, and (b) plastidic ZmBT1-1 is not the sole ADPglucose transporter in maize endosperm amyloplasts. The possible involvement of mitochondrial ZmBT1-1 in exchange between intramitochondrial AMP and cytosolic ADP is discussed., This research was partially supported by the grants BIO2010-18239, BI2013-49125-C2-2-P and BIO2016-78747-P from the Comisión Interministerial de Ciencia y Tecnología and Fondo Europeo de Desarrollo Regional (Spain) and by the ERDF project Plants as a tool for sustainable global development (No. CZ.02.1.01/0.0/0.0/16_019/0000827).