Articles
GENE REGULATION IN ONION
Article number
433_38
Pages
375 – 380
Language
Abstract
Molecular and biochemical changes associated with the initiation and development of bulbing were studied in onion (Allium cepa L cv.
Robusta). Bulb initiation was induced in two-week-old onion seedlings by transfer from 8-h short days (SD) under fluorescent lighting at 70 W m-2 and 25° C to 16-h long days (LD) at the same temperature and irradiance but with 4 X 100W lamps supplementary tungsten lighting.
An increase in the bulbing ratio was detected within 7 days of starting the LD treatment.
The LD treatments resulted in higher levels of glucose in pseudostem tissues and sucrose in leaf tissues.
Otherwise sucrose, glucose and fructose levels in leaves and pseudostem were similar in LD and SD seedlings.
Sucrose synthase levels were increased in LD pseudostems and leaves compared to SD plants but sucrose phosphate synthase was higher in SD than LD pseudostems.
A cDNA library from bulbing pseudostem tissues was differentially screened with cDNA from bulb and leaf tissues.
More than 20 clones were isolated and placed into 8 complementation groups.
ABE 1–7 were expressed strongly in pseudostem but not leaf and ALE 1 was strongly leaf-enriched.
ALE 1–7 were also expressed to variable degrees in roots.
Sequence comparison showed that ABEs 2,4 and 7 code for histones H2B1, H2A and H4, ABE 1 for o-methyl transferase, ABE 3 for HSP 70, ABE S for a basic peroxidase and ALE 1 for CAB. ABE 6 did not match with any known sequence.
Robusta). Bulb initiation was induced in two-week-old onion seedlings by transfer from 8-h short days (SD) under fluorescent lighting at 70 W m-2 and 25° C to 16-h long days (LD) at the same temperature and irradiance but with 4 X 100W lamps supplementary tungsten lighting.
An increase in the bulbing ratio was detected within 7 days of starting the LD treatment.
The LD treatments resulted in higher levels of glucose in pseudostem tissues and sucrose in leaf tissues.
Otherwise sucrose, glucose and fructose levels in leaves and pseudostem were similar in LD and SD seedlings.
Sucrose synthase levels were increased in LD pseudostems and leaves compared to SD plants but sucrose phosphate synthase was higher in SD than LD pseudostems.
A cDNA library from bulbing pseudostem tissues was differentially screened with cDNA from bulb and leaf tissues.
More than 20 clones were isolated and placed into 8 complementation groups.
ABE 1–7 were expressed strongly in pseudostem but not leaf and ALE 1 was strongly leaf-enriched.
ALE 1–7 were also expressed to variable degrees in roots.
Sequence comparison showed that ABEs 2,4 and 7 code for histones H2B1, H2A and H4, ABE 1 for o-methyl transferase, ABE 3 for HSP 70, ABE S for a basic peroxidase and ALE 1 for CAB. ABE 6 did not match with any known sequence.
Publication
Authors
B. Thomas, P. Hornby, M. D. Partis
Keywords
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