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

Autor(es)

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

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Journal of Plant Physiology; v. 168, n. 6, p. 558-565, APR 15 2011.
• Citações Web of Science: 16

Resumo

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)

• Processo FAPESP: 98/05124-8 - Conservação e uso sustentável da biodiversidade vegetal do Cerrado e da Mata Atlântica: o armazenamento de carboidratos e seu papel na adaptação e manutenção de plantas em seu habitat natural
• Beneficiário: Marcos Silveira Buckeridge
• Modalidade de apoio: Auxílio à Pesquisa - Programa BIOTA - Temático
• Processo FAPESP: 05/04139-7 - Carboidratos de plantas tropicais como moduladores de processos ecofisiológicos e indicadores de respostas a estresses ambientais
• Beneficiário: Marcia Regina Braga
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 03/04011-5 - Purificação e expressão gênica de frutano exohidrolases de rizóforos de Vernonia herbacea (Vell.) Rusby (Asteraceae)
• Beneficiário: Amanda Francine Asega
• Modalidade de apoio: Bolsas no Brasil - Doutorado