Back to Search
Start Over
Decreased expression of fructosyltransferase genes in asparagus roots may contribute to efficient fructan degradation during asparagus spear harvesting
- Source :
- C30202009230001-SC30202101060003
- Publication Year :
- 2020
- Publisher :
- Elsevier Masson SAS., 2020.
-
Abstract
- Asparagus (Asparagus officinalis L.) accumulates inulin and inulin neoseries-type fructans in root, which are synthesized by three fructosyltransferases-sucrose:sucrose 1-fructosyltransferase (1-SST, EC 2.4.1.99), fructan:fructan 1-fructosyltransferase (1-FFT, EC 2.4.1.100), and fructan:fructan 6G-fructosyltransferase (6G-FFT, EC 2.4.1.243). Fructans in roots are considered as energy sources for emerging of spears, and it has been demonstrated that a gradual decrease in root fructan content occurs during the spear harvesting season (budding and shooting up period). However, the roles of certain three fructosyltransferases during the harvest season have not yet been elucidated. Here, we investigated the variation in enzymatic activities and gene expression levels of three fructosyltransferases and examined sugar contents in roots before and during the spear harvest period. Two cDNAs, aoft2 and aoft3, were isolated from the cDNA library of roots. The respective recombinant proteins (rAoFT2 and rAoFT3), produced by Pichia pastoris, were characterized: rAoFT2 showed 1-FFT activity (producing nystose from 1-kestose), whereas rAoFT3 showed 1-SST activity (producing 1-kestose from sucrose). These reaction profiles of recombinant proteins were similar to those of native enzymes purified previously. These results indicate that aoft2 and aoft3 encoding 1-FFT and 1-SST are involved in fructan synthesis in roots. A gradual downregulation of fructosyltransferase genes and activity of respective enzymes was observed in roots during the harvest period, which also coincided with the decrease in fructooligosaccharides and increase in fructose due to fructan exohydrolase activity. These findings suggest that downregulation of fructosyltransferases genes during harvest time may contribute to efficient degradation of fructan required for the emergence of spears.
- Subjects :
- 0106 biological sciences
0301 basic medicine
Sucrose
Physiology
Inulin
Plant Science
01 natural sciences
Plant Roots
Pichia pastoris
03 medical and health sciences
chemistry.chemical_compound
Fructan
Genetics
Asparagus
Sugar
biology
Fructose
biology.organism_classification
Recombinant Proteins
Fructans
Horticulture
030104 developmental biology
chemistry
Hexosyltransferases
Saccharomycetales
Energy source
Asparagus Plant
010606 plant biology & botany
Subjects
Details
- Language :
- English
- Volume :
- 156
- Database :
- OpenAIRE
- Journal :
- Plant Physiology and Biochemistry
- Accession number :
- edsair.doi.dedup.....abd0a4f4d692368ec57b3ab5e88c44b9