title: A new isoform of thioredoxin h group in potato, SbTRXh1, regulates cold-induced sweetening of potato tubers by adjusting sucrose content.
abstract: In order to study the molecular mechanism of the cold-induced sweetening (CIS) of potato tubers, a novel isoform of thioredoxin h group, SbTRXh1, which was up-regulated early in the 4 °C storage of CIS-resistant potato (Solanum berthaultii) tubers, was cloned in present research. The genetic transformation of over-expression (OE) and RNA interference (RNAi) of SbTRXh1 into potato cv. E-Potato 3 (E3) was carried out to clarify its function in CIS regulation. The results showed that the transcripts of SbTRXh1 in either OE- or RNAi-tubers were strongly induced in 4 °C storage and quantitatively related to the reducing sugar (RS) accumulation, indicating that SbTRXh1 is involved in the CIS process of potato tubers. Regression analysis between the transcripts and protein contents of SbTRXh1 showed a very significant logarithmic relationship implying that the expression of SbTRXh1 may be mainly regulated at transcriptional level. Further monitoring the variation of the sugar contents in cold-stored tubers demonstrated a linear relationship between RS and sucrose (Suc). Thus, it can be inferred that SbTRXh1 may function in the Suc-RS pathway for CIS regulation of potato tubers.
  
  
  CONCLUSIONS
  SbTRXh1 is primarily demonstrated to be involved in the regulation of cold-induced sweetening (CIS) of potato tubers, and it may function in the Suc-RS pathway for CIS regulation.
authors.affiliation: National Centre for Vegetable Improvement-Central China, Key Laboratory of Horticultural Plant Biology-Huazhong Agricultural University, Ministry of Education, Huazhong Agricultural University, Wuhan 430070, China.
authors.forename: Tianjiu
authors.initials: T
authors.lastname: He
authors.forename: Botao
authors.initials: B
authors.lastname: Song
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.forename: Yongbin
authors.initials: Y
authors.lastname: Ou
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lin
authors.forename: Huiling
authors.initials: H
authors.lastname: Zhang
authors.forename: Conghua
authors.initials: C
authors.lastname: Xie
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D003080:Cold Temperature; D018076:DNA, Complementary / Q000235:genetics; D061353:Food Storage; D018506:Gene Expression Regulation, Plant; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D035281:Plant Tubers / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011198:Solanum tuberosum / Q000235:genetics / Q000378:metabolism*; D013213:Starch / Q000378:metabolism; D013347:Subcellular Fractions / Q000378:metabolism; D013395:Sucrose / Q000378:metabolism*; D013649:Taste / Q000235:genetics; D054480:Thioredoxin h / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D020033:Protein Isoforms; D012333:RNA, Messenger; D054480:Thioredoxin h; D013395:Sucrose; D013213:Starch