title: ci21A/Asr1 expression influences glucose accumulation in potato tubers.
abstract: Asr genes are exclusively found in the genomes of higher plants. In many species, this gene family is expressed under abiotic stress conditions and during fruit ripening. The encoded proteins have nuclear localisation and consequently a transcription factor function has been suggested. Interestingly, yeast-one-hybrid experiments revealed that a grape ASR binds to the promoter of a hexose transporter gene (VvHT1). However, the role of these proteins in planta is still elusive. By using a reverse genetics approach in potato we found that modification of Asr1 expression has no incidence on the aerial phenotype of the plant but exerts a dramatic effect in tuber. Asr1 antisense potatoes displayed decreased tuber fresh weight whereas Asr1 overexpressors had a diminished number of tubers. Moreover, overexpression lines showed lower transcript levels of a plasma membrane hexose transporter and a concomitant decrease in glucose content in parenchyma cells of potato tubers. On the same hand glucose uptake rate was also reduced in one of the overexpressing lines. It thus seems likely that Asr1 is involved in the control of hexose uptake in heterotrophic organs. In addition, the transgenic plants were characterized by several other changes in steady state metabolite levels. Results presented here support a role for ci21A/Asr1 in glucose metabolism of potato tuber.
authors.affiliation: Laboratorio de Fisiología y Biología Molecular, IFIBYNE-Conicet, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Frankel
authors.forename: Adriano
authors.initials: A
authors.lastname: Nunes-Nesi
authors.forename: Ilse
authors.initials: I
authors.lastname: Balbo
authors.forename: Jeannine
authors.initials: J
authors.lastname: Mazuch
authors.forename: Danilo
authors.initials: D
authors.lastname: Centeno
authors.forename: Norberto D
authors.initials: ND
authors.lastname: Iusem
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
authors.forename: Fernando
authors.initials: F
authors.lastname: Carrari
mesh_terms: D017931:DNA Primers; D018506:Gene Expression Regulation, Plant; D005947:Glucose / Q000378:metabolism*; D006360:Heat-Shock Proteins / Q000235:genetics*; D010788:Photosynthesis; D035261:Plant Components, Aerial / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D011198:Solanum tuberosum / Q000235:genetics* / Q000378:metabolism*
chemical_list: C104896:Ci21A protein, Solanum tuberosum; D017931:DNA Primers; D006360:Heat-Shock Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; D005947:Glucose