Increased expression of fructan 1-exohydrolase in rhizophores of Vernonia herbacea during sprouting and exposure to low temperature

Author(s)

Asega, Amanda Francine ^[1] ; do Nascimento, Joao Roberto O. ^[2] ; Carvalho, Maria Angela M. ^[1]

Affiliation

^[1] Inst Bot, Nucleo Pesquisa Fisiol & Bioquim, BR-01061970 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Lab Quim Bioquim & Bol Mol Alimentos, Dept Alimentos & Nutr Expt, BR-05508900 Sao Paulo - Brazil

• Document type: Journal article
• Source: Journal of Plant Physiology; v. 168, n. 6, p. 558-565, APR 15 2011.
• Web of Science Citations: 16

Abstract

Rhizophores of Vernonia herbacea, an Asteraceae found in the Brazilian Cerrado, store high amounts of fructans that vary in composition over the phenological cycle. Fructan 1-exohydrolase (1-FEH) activity is detectable during the sprouting phase, mainly in the proximal regions of rhizophores, of plants induced to sprout by defoliation and/or cold storage. We found an increase in 1-FEH gene expression during natural and induced sprouting and further enhancement through low-temperature treatment. Furthermore, a comparative analysis of 1-FEH gene expression in different regions of the rhizophores during the transition from dormancy to sprouting is presented. Transcripts were detected mainly in the proximal region, coinciding with high 1-FEH activity and a high concentration of free fructose. Low temperature promoted the accumulation of fructans of a low degree of polymerization (DP) and enhanced 1-FEH activity and gene expression. It is hypothesized that a set of 1-FEH proteins acts in two different ways during fructan mobilization: (1) by hydrolyzing fructo-oligosaccharides and -polysaccharides in sprouting plants (naturally or induced) for carbon supply and (2) by hydrolyzing preferably fructo-polysaccharides under low temperature to maintain the oligosaccharide pool for plant cold acclimation. (C) 2010 Elsevier GmbH. All rights reserved. (AU)

• FAPESP's process: 98/05124-8 - Conservation and sustainable use of the plant biodiversity from the cerrado and Atlantic Forest: the storage of carbohydrates and their role on the adaptation and maintainance of plants in their natural environment
• Grantee: Marcos Silveira Buckeridge
• Support Opportunities: BIOTA-FAPESP Program - Thematic Grants
• FAPESP's process: 05/04139-7 - Carbohydrates of tropical species as modulators of ecophysiological processes and as environmental stress response markers
• Grantee: Marcia Regina Braga
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 03/04011-5 - Purification and genic expression of fructan exohydrolases of rhizophores of Vernonia herbacea (Vell.) Rusby (Asteraceae)
• Grantee: Amanda Francine Asega
• Support Opportunities: Scholarships in Brazil - Doctorate