Dissecting the regulation of fructan metabolism in chicory (Cichorium intybus) hairy roots.
Fifteen per cent of higher plants accumulate fructans. Plant development, nutritional status and stress exposure all affect fructan metabolism, and while fructan biochemistry is well understood, knowledge of its regulation has remained fragmentary. Here, we have explored chicory (Cichorium intybus) hairy root cultures (HRCs) to study the regulation of fructan metabolism in sink tissues in response to environmental cues. In standard medium (SM), HRCs did not accumulate inulin. However, upon transfer to high-carbon (C)/low-nitrogen (N) medium, expression of sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructosyltransferase (1-FFT) was strongly induced and inulin accumulated. Upon return to SM, inulin was degraded, together with a coordinate decline of 1-SST and 1-FFT expression. In HRCs, cold-induced expression of fructan 1-exohydrolases (1-FEH I and IIa) was similar to cold induction in taproots, even in the absence of accumulated inulin. For high-C/low-N induction of 1-SST and 1-FFT, and cold induction of 1-FEH I and IIa, the signaling pathways were addressed. While 1-SST and 1-FFT induction was similarly prevented by inhibitors of Ca(2+) signaling, protein kinases and phosphatases, cold induction of 1-FEH I and IIa revealed distinct signaling pathways. In summary, this study has established chicory HRCs as a convenient experimental system with which to study the regulation of fructan active enzyme (FAZY) expression in heterotrophic cells.
Kusch
Ute
U
HIP, Heidelberg University, INF 360, Heidelberg D-69120, Germany.
Greiner
Steffen
S
HIP, Heidelberg University, INF 360, Heidelberg D-69120, Germany.
Steininger
Heike
H
HIP, Heidelberg University, INF 360, Heidelberg D-69120, Germany.
Meyer
Alain Denis
AD
ROOTec bioactives AG, CH-4108 Witterswil, Switzerland.
Corbière-Divialle
Hélène
H
ROOTec bioactives AG, CH-4108 Witterswil, Switzerland.
Harms
Karsten
K
ZAFES, Südzucker AG Mannheim-Ochsenfurt, Obrigheim D-67283, Germany.
Rausch
Thomas
T
HIP, Heidelberg University, INF 360, Heidelberg D-69120, Germany.
D001692:Biological Transport / Q000187:drug effects; D020013:Calcium Signaling / Q000187:drug effects; D002478:Cells, Cultured; D018651:Cichorium intybus / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D003470:Culture Media; D015536:Down-Regulation / Q000187:drug effects; D004790:Enzyme Induction / Q000187:drug effects; D005630:Fructans / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism; D006602:Hexosyltransferases / Q000096:biosynthesis / Q000235:genetics; D007444:Inulin / Q000378:metabolism; D009584:Nitrogen / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects; D001426:Bacterial Proteins
D003470:Culture Media; D005630:Fructans; D006026:Glycoside Hydrolases; D006602:Hexosyltransferases; D007444:Inulin; D009584:Nitrogen; D010749:Phosphoprotein Phosphatases; D010940:Plant Proteins; D011494:Protein Kinases; C114852:1,2-beta-fructan 1(F)-fructosyltransferase; C021451:inulosucrase; D001426:Bacterial Proteins; C044118:fructan beta-fructosidase