title: Overexpression of halophilic serine hydroxymethyltransferase in fresh water cyanobacterium Synechococcus elongatus PCC7942 results in increased enzyme activities of serine biosynthetic pathways and enhanced salinity tolerance.
abstract: Serine hydroxymethyltransferase (SHMT) catalyzes the conversion of serine to glycine and provides activated one-carbon units required for synthesis of nucleic acids, proteins and numerous biological compounds. SHMT is involved in photorespiratory pathway of oxygenic photosynthetic organisms. Accumulating evidence revealed that SHMT plays vital role for abiotic stresses such as low CO2and high salinity in plants, but its role in cyanobacteria remains to be clarified. In this study, we examined to overexpress the SHMT from halotolerant cyanobacterium Aphanothece halophytica in freshwater cyanobacterium, Synechococcus elongatus PCC7942. The transformed cells did not show an obvious phenotype under non-stress condition, but exhibited more tolerance to salinity than the control cells harboring vector only under high salinity. Elevated levels of enzymes in phosphorylated serine biosynthetic pathway and photorespiration pathway were observed in the transformed cells. Glycine level was also increased in the transformed cells. Physiological roles of SHMT for salt tolerance were discussed.
authors.affiliation: Research Institute of Meijo University, Nagoya, 468-8502, Japan.|Department of Microbiology, Faculty of Science, Chulalongkorn University, Patumwan, Bangkok, 10330, Thailand.
authors.forename: Rungaroon
authors.initials: R
authors.lastname: Waditee-Sirisattha
authors.affiliation: Graduate School of Environmental and Human Sciences, Meijo University, Nagoya, 468-8502, Japan.
authors.forename: Hakuto
authors.initials: H
authors.lastname: Kageyama
authors.affiliation: Graduate School of Environmental and Human Sciences, Meijo University, Nagoya, 468-8502, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Tanaka
authors.affiliation: Faculty of Science and Technology, Meijo University, Nagoya, 468-8502, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Fukaya
authors.affiliation: Research Institute of Meijo University, Nagoya, 468-8502, Japan. takabe@meijo-u.ac.jp.|Graduate School of Environmental and Human Sciences, Meijo University, Nagoya, 468-8502, Japan. takabe@meijo-u.ac.jp.
authors.forename: Teruhiro
authors.initials: T
authors.lastname: Takabe
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D053898:Biosynthetic Pathways; D005618:Fresh Water / Q000382:microbiology; D012696:Glycine Hydroxymethyltransferase / Q000235:genetics* / Q000378:metabolism; D010788:Photosynthesis; D055049:Salt Tolerance; D012694:Serine / Q000096:biosynthesis*; D046940:Synechococcus / Q000201:enzymology / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012694:Serine; D012696:Glycine Hydroxymethyltransferase
keywords: Cyanobacteria; Halotolerant; Photorespiration; Salt stress; Serine; Serine hydroxymethyltransferase