Internode length in Pisum

Ingram, Timothy J.; Reid, James B.; Murfet, Ian C.; Gaskin, Paul; Willis, Christine L.; MacMillan, Jake

doi:10.1007/bf00429763

Cited by 212 publications

(24 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It has been previously established that 3p"-hydroxylation is important in the regulation of stem growth (Phinney and Spray, 1982;Ingram et al, 1984). The results of the studies presented here indicate that, in addition to the critical roles the properties and compartmentalization of the active GAs play in stem growth, molecular regulatory mechanisms also play an important part in the control of GA biosynthesis.…”

Section: E M T Q K Y R P a T H A T@f N K A 348supporting

confidence: 53%

Isolation of the Arabidopsis GA4 locus.

1995

View full text Add to dashboard Cite

Progeny from a transgenic Arabidopsis plant generated by the Agrobacterium root transformation procedure were found to segregate for a gibberellin (GA)-responsive semidwarf phenotype. Complementation analysis with genetically characterized GA-responsive mutants revealed that the transgenic plant has an insertional mutation (ga4-2) that is an allele of the ga4 locus. The semidwarf phenotype of ga4-2 is inherited as a recessive mutation that cosegregates with both the T-DNA insert and the kanamycin resistance trait. DNA gel blot analysis indicated that the insertion site contains a complex T-DNA unit. A genomic library was constructed with DNA from the tagged ga4 mutant; a DNA clone was isolated from the library that flanks the T-DNA insert. The plant sequence isolated from this clone was used to isolate the corresponding full-length genomic and cDNA clones from wild-type libraries. DNA sequence comparison of the clones to the existing data bases suggests that they encode a hydroxylase. This conclusion is in agreement with a biochemical study that indicated that the ga4 mutant is deficient in 3P-hydroxylase in the GA biosynthetic pathway of Arabidopsis. FINA gel blot analysis showed that the message is ubiquitously expressed in different tissues of Arabidopsis but most abundantly in the silique. Unexpectedly, a higher leve1 of transcription was detected i n the ethyl methanesulfonate-induced ga4 mutant, and this overexpression was repressed by treatment with exogenous GA.

show abstract

Section: E M T Q K Y R P a T H A T@f N K A 348supporting

confidence: 53%

Isolation of the Arabidopsis GA4 locus.

1995

View full text Add to dashboard Cite

show abstract

“…GA-deficient mutants have proven important in defining the genes involved in GA biosynthesis (e.g. Ingram et al, 1984;Lester et al, 1997). The lh mutants of pea (Pisum sativum) are GA deficient, and the early internodes are reduced to nearly one-third the length of the wild type (Reid, 1986).…”

mentioning

confidence: 99%

The Pea Gene LH Encodes ent-Kaurene Oxidase

et al. 2004

Self Cite

View full text Add to dashboard Cite

The pea (Pisum sativum) homolog, PsKO1, of the Arabidopsis GA3 gene was isolated. It codes for a cytochrome P450 from the CYP701A subfamily and has ent-kaurene oxidase (KO) activity, catalyzing the three step oxidation of ent-kaurene to ent-kaurenoic acid in the gibberellin (GA) biosynthetic pathway when expressed in yeast (Saccharomyces cerevisiae). PsKO1 is encoded by the LH gene because in three independent mutant alleles, lh-1, lh-2, and lh-3, PsKO1 has altered sequence, and the lh-1 allele, when expressed in yeast, failed to metabolize ent-kaurene. The lh mutants of pea are GA deficient and have reduced internode elongation and root growth. One mutant (lh-2) also causes a large increase in seed abortion. PsKO1 (LH) is expressed in all tissues examined, including stems, roots, and seeds, and appears to be a single-copy gene. Differences in sensitivity to the GA synthesis inhibitor, paclobutrazol, between the mutants appear to result from the distinct nature of the genetic lesions. These differences may also explain the tissue-specific differences between the mutants.

show abstract

“…In many higher plants, such as maize (2,3) and pea (4), the early-13-hydroxylation pathway (GA53, GA44, GA19, GA17, GA20, GA29, GA1, and GA8; for structures see Fig. 1) leads to GA1, which is probably the active member of this series in the control of stem growth (2,5). In addition, there is a parallel non-3,13-hydroxylation pathway (GA12, GA15, GA24, GA25, GA9, and GA51), as found in pea embryos (4).…”

mentioning

confidence: 99%

Endogenous gibberellins in Arabidopsis thaliana and possible steps blocked in the biosynthetic pathways of the semidwarf ga4 and ga5 mutants.

Talón

Koornneef

Zeevaart

1990

Proc. Natl. Acad. Sci. U.S.A.

206

213

View full text Add to dashboard Cite

Twenty gibberellins (GAs) have been identified in extracts from shoots of the Landsberg erecta line of Arabidopsis thiliana by full-scan gas chromatography-mass spectrometry and Kovats retention indices. Eight of them are members of the early-13-hydroxylation pathway (GA'3, GA44, GA,9, GA17, GA209 GA,, GA29, and GA8), six are members of the early-3-hydroxylation pathway (GA37, GA27, GA36, GA,3, GA4, and GA34), and the remaining six are members of the non-3,13-hydroxylation pathway (GA,2, GA15, GA24, GA25, GA9, and GA51). Seven of these GAs were quantified in the Landsberg erecta line ofArabidopsis and in the semidwarf ga4 and gaS mutants by gas chromatography-selected ion monitoring (SIM) using internal standards. The relative levels of the remaining 13 GAs were compared by the use of ion intensities only. In comparison with the Landsberg erecta line, the ga4 mutant had reduced levels of the 3-hydroxy-and 3,13-dihydroxy-GAs, and it accumulated the 13-hydroxy-GAs, except GA53, and the non-3,13-hydroxy-GAs, except GA,2. The GA4 gene encodes, therefore, a protein with 3(3-hydroxylation activity. The gaS mutant had reduced levels of the C,9-GAs, which indicates that the product of the GAS gene catalyzes the elimination of C-20 at the aldehyde level. The gas mutant also had increased levels of certain C20-GAs, which indicates existence of an additional control, possibly hydroxylation of C-20.The growth-response data, as well as the accumulation of GA9 in thega4 mutant, indicate that GA9 is not active inArabidopsis, but it must be 3,B-hydroxylated to GA4 to become bioactive. It is concluded that the reduced levels of the 3.-hydroxy-GAs, GA, and GA4, are the cause of the semidwarf growth habit of both mutants.The biosynthesis of gibberellins (GAs) after GA12-aldehyde involves a series of oxidative steps that leads to the formation of bioactive GAs (1). Several GA pathways differing in hydroxylation pattern have been detected in different species. In many higher plants, such as maize (2, 3) and pea (4), the early-13-hydroxylation pathway (GA53, GA44, GA19, GA17, GA20, GA29, GA1, and GA8; for structures see Fig. 1) leads to GA1, which is probably the active member of this series in the control of stem growth (2, 5). In addition, there is a parallel non-3,13-hydroxylation pathway (GA12, GA15, GA24, GA25, GA9, and GA51), as found in pea embryos (4).Hydroxylation at the /3,-position may also occur at intermediate levels in this pathway, generating 3-hydroxylated GAs (GA37, GA36, GA13, and GA4), as found in bean embryos (6) and pumpkin endosperm (7). Although a number of cell-free systems for GA conversions have been described (1), purification of GA hydroxylases has turned out to be difficult, because they are low-abundance proteins and very unstable (6,8,9). Consequently, nothing is known at present about the mechanisms by which these enzymes are regulated at the molecular level.In Arabidopsis thaliana, a plant species suitable for molecular genetic studies (10, 11), a number of GA-responsive dwarf mutants have bee...

show abstract

Internode length in Pisum

Cited by 212 publications

References 38 publications

Isolation of the Arabidopsis GA4 locus.

Isolation of the Arabidopsis GA4 locus.

The Pea Gene LH Encodes ent-Kaurene Oxidase

Endogenous gibberellins in Arabidopsis thaliana and possible steps blocked in the biosynthetic pathways of the semidwarf ga4 and ga5 mutants.

Contact Info

Product

Resources

About