Molecular dissection of the role of histidine in nickel hyperaccumulation in Thalspi goesingense (Halacsy)
To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, the authors investigated the regulation of His biosynthesis at both the molecular and biochemical levels. Three T. goesingense cDNAs encoding the following His biosynthetic enzymes, ATP phosphoribosyltransferase, imidazoleglycerol phosphate dehydratase, and histidinol dehydrogenase, were isolated by functional complementation of Escherichia coli His autotrophs. Northern analysis of THJG1, THD1, and THB1 gene expression revealed that each gene is expressed in both roots and shoots, but at the concentrations and dosage times of Ni treatment used in this study, these genes failed to show any regulation by Ni. The authors were also unable to observe any increases in the concentration of free His in root, shoot, or xylem sap of T. goesingense in response to Ni exposure. X-ray absorption spectroscopy of root and shoot tissue from T. goesingense and the non-accumulator species Thlaspi reverse revealed no major differences in the coordination of Ni by His in these tissues. They therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.
- Research Organization:
- Northern Arizona Univ., Flagstaff, AZ (US)
- Sponsoring Organization:
- USDOE; German Academic Exchange Service
- DOE Contract Number:
- FG07-98ER20295
- OSTI ID:
- 20006198
- Journal Information:
- Plant Physiology (Bethesda), Vol. 121, Issue 4; Other Information: PBD: Dec 1999; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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