Bahaji, Abdellatif

Profile Picture

Email Address

person.page.identifierURI

https://academica-e.unavarra.es/handle/2454/48646

Birth Date

Job Title

Last Name

Bahaji

First Name

Abdellatif

person.page.departamento

Instituto de Agrobiotecnología (IdAB)

person.page.instituteName

ORCID

0000-0002-5270-497X

person.page.observainves

person.page.upna

810260

Name

Filters

2011 - 20152
Reset filters

Settings

Subject: Carbohydrate metabolism ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    PublicationOpen Access
    Sucrose synthase activity in the sus1/sus2/sus3/sus4 Arabidopsis mutant is sufficient to support normal cellulose and starch production
    (National Academy of Sciences, 2011) Baroja Fernández, Edurne; Muñoz Pérez, Francisco José; Li, Jun; Bahaji, Abdellatif; Almagro Zabalza, Goizeder; Montero Macarro, Manuel; Etxeberria, Ed; Hidalgo Cruz, Maite; Sesma Pascual, María Teresa; Pozueta Romero, Javier; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    Sucrose synthase (SUS) catalyzes the reversible conversion of sucrose and a nucleoside diphosphate into the corresponding nucleoside diphosphate-glucose and fructose. In Arabidopsis, a multigene family encodes six SUS (SUS1-6) isoforms. The involvement of SUS in the synthesis of UDP-glucose and ADP-glucose linked to Arabidopsis cellulose and starch biosynthesis, respectively, has been questioned by Barratt et al. [(2009) Proc Natl Acad Sci USA 106:13124–13129], who showed that (i) SUS activity in wild type (WT) leaves is too low to account for normal rate of starch accumulation in Arabidopsis, and (ii) different organs of the sus1/sus2/sus3/sus4 SUS mutant impaired in SUS activity accumulate WT levels of ADP-glucose, UDP-glucose, cellulose and starch. However, these authors assayed SUS activity under unfavorable pH conditions for the reaction. By using favorable pH conditions for assaying SUS activity, in this work we show that SUS activity in the cleavage direction is sufficient to support normal rate of starch accumulation in WT leaves. We also demonstrate that sus1/sus2/sus3/sus4 leaves display WT SUS5 and SUS6 expression levels, whereas leaves of the sus5/sus6 mutant display WT SUS1–4 expression levels. Furthermore, we show that SUS activity in leaves and stems of the sus1/sus2/sus3/sus4 and sus5/sus6 plants is ~85% of that of WT leaves, which can support normal cellulose and starch biosynthesis. The overall data disprove Barratt et al. (2009) claims, and are consistent with the possible involvement of SUS in cellulose and starch biosynthesis in Arabidopsis.
  • Thumbnail Image
    PublicationOpen Access
    Characterization of multiple SPS knockout mutants reveals redundant functions of the four Arabidopsis sucrose phosphate synthase isoforms in plant viability, and strongly indicates that enhanced respiration and accelerated starch turnover can alleviate the blockage of sucrose biosynthesis
    (Elsevier, 2015) Bahaji, Abdellatif; Baroja Fernández, Edurne; Ricarte Bermejo, Adriana; Sánchez López, Ángela María; Muñoz Pérez, Francisco José; Baslam, Marouane; Almagro Zabalza, Goizeder; Sesma Pascual, María Teresa; Pozueta Romero, Javier; IdAB. Instituto de Agrobiotecnología / Agrobioteknologiako Institutua; Universidad Pública de Navarra / Nafarroako Unibertsitate Publikoa
    We characterized multiple knock-out mutants of the four Arabidopsis sucrose phosphate synthase (SPSA1, SPSA2, SPSB and SPSC) isoforms. Despite their reduced SPS activity, spsa1/spsa2, spsa1/spsb, spsa2/spsb, spsa2/spsc, spsb/spsc, spsa1/spsa2/spsb and spsa2/spsb/spsc mutants displayed wild type (WT) vegetative and reproductive morphology, and showed WT photosynthetic capacity and respiration. In contrast, growth of rosettes, flowers and siliques of the spsa1/spsc and spsa1/spsa2/spsc mutants was reduced compared with WT plants. Furthermore, these plants displayed a high dark respiration phenotype. spsa1/spsb/spsc and spsa1/spsa2/spsb/spsc seeds poorly germinated and produced aberrant and sterile plants. Leaves of all viable sps mutants, except spsa1/spsc and spsa1/spsa2/spsc, accumulated WT levels of nonstructural carbohydrates. spsa1/spsc leaves possessed high levels of metabolic intermediates and activities of enzymes of the glycolytic and tricarboxylic acid cycle pathways, and accumulated high levels of metabolic intermediates of the nocturnal starch-to-sucrose conversion process, even under continuous light conditions. Results presented in this work show that SPS is essential for plant viability, reveal redundant functions of the four SPS isoforms in processes that are important for plant growth and nonstructural carbohydrate metabolism, and strongly indicate that accelerated starch turnover and enhanced respiration can alleviate the blockage of sucrose biosynthesis in spsa1/spsc leaves.