Molecular Dissection of the Role of Histidine in Nickel Hyperaccumulation in Thlaspi goesingense (Hálácsy)1
AUTOR(ES)
Persans, Michael W.
FONTE
American Society of Plant Physiologists
RESUMO
To understand the role of free histidine (His) in Ni hyperaccumulation in Thlaspi goesingense, we 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 (THG1, GenBank accession no. AF003347), imidazoleglycerol phosphate dehydratase (THB1, GenBank accession no. AF023140), and histidinol dehydrogenase (THD1, GenBank accession no. AF023141) were isolated by functional complementation of Escherichia coli His auxotrophs. Northern analysis of THG1, 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. We 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 arvense revealed no major differences in the coordination of Ni by His in these tissues. We therefore conclude that the Ni hyperaccumulation phenotype in T. goesingense is not determined by the overproduction of His in response to Ni.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=59479Documentos Relacionados
- The Role of Metal Transport and Tolerance in Nickel Hyperaccumulation by Thlaspi goesingense Halacsy.
- Functional activity and role of cation-efflux family members in Ni hyperaccumulation in Thlaspi goesingense
- Increased Glutathione Biosynthesis Plays a Role in Nickel Tolerance in Thlaspi Nickel HyperaccumulatorsW⃞
- Bacterial Communities Associated with Flowering Plants of the Ni Hyperaccumulator Thlaspi goesingense
- Hyperaccumulation of Cadmium and Zinc in Thlaspi caerulescens and Arabidopsis halleri at the Leaf Cellular Level1