Journal Article

Cloning, Characterization and Functional Analysis of a 1-FEH cDNA from <i>Vernonia herbacea</i> (Vell.) Rusby

Amanda Francine Asega, João Roberto O. do Nascimento, Lindsey Schroeven, Wim Van den Ende and Maria Angela M. Carvalho

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 49, issue 8, pages 1185-1195
Published in print August 2008 | ISSN: 0032-0781
Published online June 2008 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pcn094
Cloning, Characterization and Functional Analysis of a 1-FEH cDNA from Vernonia herbacea (Vell.) Rusby

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  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

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Variations in the inulin contents have been detected in rhizophores of Vernonia herbacea during the phenological cycle. These variations indicate the occurrence of active inulin synthesis and depolymerization throughout the cycle and a role for this carbohydrate as a reserve compound. 1-Fructan exohydrolase (1-FEH) is the enzyme responsible for inulin depolymerization, and its activity has been detected in rhizophores of sprouting plants. Defoliation and low temperature are enhancer conditions of this 1-FEH activity. The aim of the present work was the cloning of this enzyme. Rhizophores were collected from plants induced to sprout, followed by storage at 5°C. A full length 1-FEH cDNA sequence was obtained by PCR and inverse PCR techniques, and expressed in Pichia pastoris. Cold storage enhances FEH gene expression. Vh1-FEH was shown to be a functional 1-FEH, hydrolyzing predominantly β-2,1 linkages, sharing high identity with chicory FEH sequences, and its activity was inhibited by 81% in the presence of 10 mM sucrose. In V. herbacea, low temperature and sucrose play a role in the control of fructan degradation. This is the first study concerning the cloning and functional analysis of a 1-FEH cDNA of a native species from the Brazilian Cerrado. Results will contribute to understanding the role of fructans in the establishment of a very successful fructan flora of the Brazilian Cerrado, subjected to water limitation and low temperature during winter.

Keywords: Asteraceae; Brazilian Cerrado; 1-FEH cloning; Functional analysis; Underground reserve organs; Vernonia herbacea

Journal Article.  6250 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

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