Members of arabinogalactan protein family in Arabidopsis pollen development

• Mário Costa ^[1] ; Luís Gustavo Pereira ^[1] ; Sílvia Coimbra ^[1]
  1. [1] Universidade Do Porto

     Universidade Do Porto

     Santo Ildefonso, Portugal

     
• Localización: SEFV 2011: programa de sesiones y resúmenes de conferencias plenarias e invitadas / coord. por Vicent Arbona Mengual, Rosa María Pérez Clemente, María Fernanda López Climent, Aurelio Gómez Cadenas, 2011, ISBN 978-84-8021-805-4, pág. 60
• Idioma: inglés
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• Resumen

  • Plant gametophyte development represents a unique period of cytoplasm reorganization,accompanied by enormous changes at the molecular level. Among the genes, or gene families,whose expression is reprogrammed during the transition from a sporophytic to a gametophytictype of development are the arabinogalactan protein (AGP) genes. Arabinogalactan proteinsbelong to a large family of wall proteoglycans, the proline/hydroxyproline-rich glycoproteins.We have previously identified two Arabidopsis AGP genes (AGP6 and AGP11) expressed inmale gametophyte which apparently show functional redundancy (Coimbra et al., 2009); thus, adouble knockout mutant was obtained, which showed segregation distortion, suggesting that thegametophyte generation was affected.AGP6 and AGP11 are two Arabidopsis genes which are strongly and specifically expressed inpollen grains and pollen tubes (Pereira et al., 2006). Experiments performed in our laboratoryintegrating reverse genetics and other experimental approaches, led us to believe that theobserved fertility reduction in agp6 agp11 double mutant is due to abortion of pollen grainsduring development (Coimbra et al., 2009). We have further characterized the anthers andpollen of agp6 agp11 double null mutants and concluded that AGP6 and AGP11 are necessaryfor the proper pollen tube growth as well as for preventing untimely pollen grain germination(Coimbra et al., 2010).Whether AGPs are predominantly structural, or nutrient-providers, or signaling molecules, isyet to be determined. We are committed to search for AGP-specific ligands, recently identifiedfor tobacco pistil AGPs (Lee et al., 2008), to try to bring some clarification for the biologicalway of action of this ubiquitous class of plant proteoglycans. For this assignment we performedmicroarray experiments in our agp6 agp11 double null mutant pollen tube. The results of thisexperiment will be presented and discussed.