Cloning, characterization and functional analysis of novel 6-kestose exohydrolases (6-KEHs) from wheat (Triticum aestivum)
Cereals accumulate graminan-type fructans which are subject to stress-related degradation by fructan 1-exohydrolases (1-FEHs) and fructan 6-exohydrolases (6-FEHs). To find new FEH genes related to freezing tolerance, a cold-hardened wheat crown cDNA library was screened. Here we report the cloning,...
| Veröffentlicht in: | The New phytologist. - 1979. - 166(2005), 3 vom: 15. Juni, Seite 917-32 |
|---|---|
| 1. Verfasser: | |
| Weitere Verfasser: | , , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2005
|
| Zugriff auf das übergeordnete Werk: | The New phytologist |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Isoenzymes Glycoside Hydrolases EC 3.2.1.- |
| Zusammenfassung: | Cereals accumulate graminan-type fructans which are subject to stress-related degradation by fructan 1-exohydrolases (1-FEHs) and fructan 6-exohydrolases (6-FEHs). To find new FEH genes related to freezing tolerance, a cold-hardened wheat crown cDNA library was screened. Here we report the cloning, purification and characterization of two novel 6-kestosidase (6-KEH) isoenzymes from wheat crowns (Triticum aestivum). Functional characterization in Pichia pastoris confirmed the extreme substrate selectivity for the fructan trisaccharide 6-kestose. Northern blotting showed that 6-KEH transcripts were constantly detected at the same level from autumn to winter in crown but not in leaf tissues. Apoplastic fluid isolations and activity measurements strongly suggest that 6-KEH is localized in the apoplast. It is proposed that 6-KEHs, together with other FEHs, might be involved in the breakdown of apoplastic fructans which may fulfil a role as membrane protectors under stress. Alternatively, a role in signalling processes, or in the degradation of exogenous 6-kestose from bacterial origin, cannot be excluded |
|---|---|
| Beschreibung: | Date Completed 29.06.2005 Date Revised 31.03.2022 published: Print CommentIn: New Phytol. 2005 Jun;166(3):708-9. - PMID 15869633 Citation Status MEDLINE |
| ISSN: | 1469-8137 |