TY  - THES
T1  - The role of nicotianamine in the metal homeostasis of Arabidopsis thaliana
A1  - Schuler,Mara
Y1  - 2011/09/19
N2  - The non-proteinogenic amino acid nicotianamine (NA)chelates and transports essential metal ions in plants. The enhancing effect of NA on the bioavailability of metals makes it appealing for biofortification approaches. The goal of this project was the localization of NA activity and the elucidation of a concrete function of NA in Fe and Cu translocation throughout the plant using the model plant Arabidopsis thaliana. 
Arabidopsis has four NICOTIANAMINE SYNTHASE (NAS) genes. To investigate NA function two quadruple nas mutants, named nas4x-1 and nas4x-2 were analyzed to study NA function in Arabidopsis: nas4x-2 had a full loss of NAS function, was sterile, and suffered from severe chlorosis in young leaves. nas4x-1 had residual NA contents, was still fertile and developed a interveinal leaf chlorosis upon transition from vegetative to reproductive stage. The obtained results indicate that NA participates in the phloem-dependent Fe transport and in the phloem- and xylem-dependent Cu transport in plants. Thereby NA has a distinct function in the phloem unloading process of metals in young growing tissues, reproductive floral organs and seeds. Moreover, NA is required for the remobilization of metals from old leaves to the inflorescence. These findings are fundamental for plant manipulation approaches to increase the amount of bioavailable Fe in seeds through the genetic modification of the NAS genes.
KW  - Ackerschmalwand
KW  - Metall
KW  - Eisen
KW  - Bioverfügbarkeit
KW  - Nicotianaminsynthase
KW  - Transport
KW  - Xylem
KW  - Phloëm
CY  - Saarbrücken
PB  - Universitäts- und Landesbibliothek
AD  - Postfach 151141, 66041 Saarbrücken
UR  - http://scidok.sulb.uni-saarland.de/volltexte/2011/4327
ER  -