Abstract
Several early-flowering flax (Linum usitatissimum L.) lines were derived from treatment of germinating seeds with 5-azacytidine in 1990. These lines are also shorter, have fewer leaves, and their DNA is hypomethylated, relative to their corresponding controls. The work presented in this thesis used early-flowering and control lines of the Royal (R) flax genotype, and the Large (L) flax genotroph. Firstly, levels of cytosine methylation were measured over a 24-hour period in the early-flowering line RE2 and its control (RC), using an HPLC method. Secondly, to determine the response of the flax lines to short-day conditions, control and early-flowering lines from both L and R were grown in either 8-hour-day or ambient, longday light conditions, and were compared in a number of aspects of development. Thirdly, primers for five putative flax flowering genes (SOC1, COL, ADG1, GAI, and AP1) were designed and a semi-quantitative PCR method was used to establish developmental expression profiles in leaves and shoot tips of RC and RE2 in order to detect differences in expression that may have resulted from the original demethylation treatment. Methylation was found to remain constant in RC and RE2 over the 24-hour period in all three tissues examined. In the short-day experiment the early-flowering lines differed from controls in a number of parameters, but the most notable were that the treatment delayed flowering and increased the number of leaves produced in all lines, but had less of an effect on the early-flowering lines. Expression patterns for the five genes examined indicated that they are all expressed in both leaves and shoot tips, and for most genes there was no indication that their expression had been altered by the demethylation treatment. However, AP1 expression was higher in leaves of RE2 than those of RC, and was found to reach higher levels in the buds of RE2 than those of RC. These expression differences may be the result of demethylation of a gene upstream of API that was affected by the demethylation treatment. The results of these experiments further demonstrate the differences between the early-flowering lines and their controls, and will help elucidate the genetic basis for these differences.
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Claims 9
Claim · model-written summary
Cytosine methylation remained constant over 24 hours in the control line RC and the early-flowering line RE2 in all three tissues examined.
- Taxon
- Linum usitatissimum
Linum usitatissimume1 - Material
- RC and RE2e0
- Outcome
- Methylatione0
- Qualifier
- remain constante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Methylation was found to remain constant in RC and RE2 over the 24-hour period in all three tissues examined”
e1“Linum usitatissimum”
Claim · model-written summary
The short-day (8-hour-day) treatment delayed flowering in the flax lines relative to ambient long-day light.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Treatment
- 8-hour-daye2
- Outcome
- floweringe0
- Direction
- delayede0
- Comparator
- ambient, longday light conditionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the treatment delayed flowering”
e1“Linum usitatissimum”
e2“8-hour-day or ambient, longday light conditions”
Claim · model-written summary
The short-day treatment increased the number of leaves produced in all flax lines relative to ambient long-day light.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Treatment
- 8-hour-daye2
- Outcome
- number of leaves producede0
- Direction
- increasede0
- Qualifier
- in all linese0
- Comparator
- ambient, longday light conditionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the number of leaves produced in all lines”
e1“Linum usitatissimum”
e2“8-hour-day or ambient, longday light conditions”
Claim · model-written summary
The short-day treatment had less of an effect on the early-flowering lines than on the controls.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Material
- early-flowering linese0
- Treatment
- 8-hour-daye2
- Outcome
- less of an effecte0
- Direction
- lesse0
- Comparator
- ambient, longday light conditionse2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“had less of an effect on the early-flowering lines”
e1“Linum usitatissimum”
e2“8-hour-day or ambient, longday light conditions”
Claim · model-written summary
The five putative flowering genes SOC1, COL, ADG1, GAI and AP1 are all expressed in both leaves and shoot tips of flax.
- Taxon
- Linum usitatissimumLinum usitatissimume2
- Organ / stage
- leaves and shoot tipse0
- Gene
- SOC1, COL, ADG1, GAI, and AP1e1
- Outcome
- expressede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“they are all expressed in both leaves and shoot tips”
e1“SOC1, COL, ADG1, GAI, and AP1”
e2“Linum usitatissimum”
Claim · model-written summary
For most of the examined genes there was no indication that expression was altered by the demethylation treatment.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Treatment
- demethylation treatmente0
- Outcome
- expressione0
- Direction
- no indication that their expression had been alterede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for most genes there was no indication that their expression had been altered by the demethylation treatment”
e1“Linum usitatissimum”
Claim · model-written summary
AP1 expression was higher in leaves of RE2 than in leaves of RC.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Material
- RE2e0
- Organ / stage
- leavese0
- Gene
- AP1e0
- Outcome
- AP1 expressione0
- Direction
- highere0
- Comparator
- RCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AP1 expression was higher in leaves of RE2 than those of RC”
e1“Linum usitatissimum”
Claim · model-written summary
AP1 expression reached higher levels in the buds of RE2 than in the buds of RC.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Material
- RE2e0
- Organ / stage
- budse0
- Gene
- AP1e0
- Outcome
- AP1 expressione0
- Direction
- highere0
- Comparator
- RCe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“AP1 expression was higher in leaves of RE2 than those of RC, and was found to reach higher levels in the buds of RE2 than those of RC”
e1“Linum usitatissimum”
Claim · model-written summary
The authors suggest the AP1 expression differences may result from demethylation of a gene upstream of AP1 affected by the demethylation treatment.
- Taxon
- Linum usitatissimumLinum usitatissimume1
- Treatment
- demethylation treatmente0
- Gene
- a gene upstream of APIe0
- Outcome
- expression differencese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These expression differences may be the result of demethylation of a gene upstream of API that was affected by the demethylation treatment”
e1“Linum usitatissimum”