Mendel's Stem Length Gene (Le) Encodes a Gibberellin 3b-Hydroxylase

Lester, Diane R.; Ross, John; Davies, Peter J.; Reid, James B.

doi:10.2307/3870393

Cited by 54 publications

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“…Another key GA gene from pea is Mendel's LE, also known as the 3-oxidase gene PsGA3ox1 (Lester et al, 1997;Martin et al, 1997). Mendel exploited the dwarf stature of mutant le-1 shoots in his original genetics experiments, but it is interesting to note that the roots of le-1 plants (and of other le mutants) are indistinguishable from the wild type, and contain normal GA levels (Yaxley et al, 2001).…”

Section: Discussionmentioning

confidence: 99%

“…The expression levels of the 3-oxidase genes PsGA3ox1 (also known as Mendel's LE; Lester et al, 1997;Martin et al, 1997) and PsGA3ox2 were measured in the shoot and root tissue of 6-d-old pea seedlings using real-time PCR. PsGA3ox1 was more highly expressed in the shoot compared with root tissue, with an approximate 2-fold difference (P , 0.001; Fig.…”

Section: La and Cry Encode Della Proteinsmentioning

confidence: 99%

“…A single clone containing the 5# end of the gene was isolated, sequenced, and then ligated into pGem-T Easy (Clontech) and expressed in Escherichia coli. The functional activity of the expression product was tested as before (Lester et al, 1997), using [ 14 C]GA 20 as a substrate.…”

Section: Cloning Of La Cry and Psga3ox2mentioning

confidence: 99%

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The Pea DELLA Proteins LA and CRY Are Important Regulators of Gibberellin Synthesis and Root Growth

et al. 2008

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The theory that bioactive gibberellins (GAs) act as inhibitors of inhibitors of plant growth was based originally on the slender pea (Pisum sativum) mutant (genotype la cry-s), but the molecular nature of this mutant has remained obscure. Here we show that the genes LA and CRY encode DELLA proteins, previously characterized in other species (Arabidopsis [Arabidopsis thaliana] and several grasses) as repressors of growth, which are destabilized by GAs. Mutations la and cry-s encode nonfunctional proteins, accounting for the fact that la cry-s plants are extremely elongated, or slender. We use the la and cry-s mutations to show that in roots, DELLA proteins effectively promote the expression of GA synthesis genes, as well as inhibit elongation. We show also that one of the DELLAregulated genes is a second member of the pea GA 3-oxidase family, and that this gene appears to play a major role in pea roots.It is well known that primary root growth is strongly influenced by the plant hormone GA (Davies, 2004). For example, the application of bioactive GA to roots treated with the growth inhibitor ancymidol completely restored growth to that of the untreated plants (Tanimoto, 1991). Yaxley et al. (2001) established the importance of GAs for root growth in peas (Pisum sativum) by using a variety of GA-deficient mutant plants. In the na-1 mutant, for example, root GA 1 levels, and root elongation, were significantly reduced compared with wild-type plants, and when the GA 1 content was restored to wild-type levels, so too was root elongation.The GAs act by destabilizing the growth inhibitory DELLA proteins (Peng et al., 1997;Harberd et al., 1998;Silverstone et al., 2001;Alvey and Harberd, 2005). In other words, GA acts as an ''inhibitor of an inhibitor '' (Harberd et al., 1998). Interestingly, there is also evidence that DELLA proteins promote the biosynthesis of active GAs. For example, in the Arabidopsis (Arabidopsis thaliana) DELLA mutant rga, the expression of the biosynthesis gene GA4 is reduced, indicating that high DELLA protein levels are associated with an up-regulation of GA synthesis genes (Silverstone et al., 2001 (Silverstone et al., 1998;Gubler et al., 2002). However, the available evidence indicates greater redundancy in dicots compared with monocots (Ikeda et al., 2001;Thomas and Hedden, 2006). There have been five DELLA genes isolated from Arabidopsis (GAI, RGA, RGL1, RGL2, and RGL3), yet only one in rice (SLR1), barley (SLN1), and maize (Zea mays; D8; Peng et al., 1997Peng et al., , 1999Silverstone et al., 1998;Ikeda et al., 2001;Chandler et al., 2002;Gubler et al., 2002), with the possibility of another DELLA gene in maize (D9; accession no. ABI84225). It should be noted, however, that DELLAs have been studied in fewer dicot model species than in monocot species. To date, DELLA-encoding genes from pea have not been reported, even though observations on the slender phenotype of pea triggered the early suggestion that GA acts an inhibitor of an inhibitor (Brian, 1957). The elongated slender phenotype, con...

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Section: Discussionmentioning

confidence: 99%

Section: La and Cry Encode Della Proteinsmentioning

confidence: 99%

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The Pea DELLA Proteins LA and CRY Are Important Regulators of Gibberellin Synthesis and Root Growth

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“…LE was the second of Mendel's genes to be cloned when in 1997 two groups working independently reported the successful isolation of this gene (Lester et al 1997;Martin et al 1997). This was made possible by the previous isolation (by transposon tagging) of a putative GA 3b-hydroxylase gene from Arabidopsis, GA4 (Chiang et al 1995).…”

Section: Stem Lengthmentioning

confidence: 99%

Mendel’s Genes: Toward a Full Molecular Characterization

Reid

Ross

2011

Genetics

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The discipline of classical genetics is founded on the hereditary behavior of the seven genes studied by Gregor Mendel. The advent of molecular techniques has unveiled much about the identity of these genes. To date, four genes have been sequenced: A (flower color), LE (stem length), I (cotyledon color), and R (seed shape). Two of the other three genes, GP (pod color) and FA (fasciation), are amenable to candidate gene approaches on the basis of their function, linkage relationships, and synteny between the pea and Medicago genomes. However, even the gene (locus) identity is not known for certain for the seventh character, the pod form, although it is probably V. While the nature of the mutations used by Mendel cannot be determined with certainty, on the basis of the varieties available in Europe in the 1850s, we can speculate on their nature. It turns out that these mutations are attributable to a range of causes-from simple base substitutions and changes to splice sites to the insertion of a transposon-like element. These findings provide a fascinating connection between Mendelian genetics and molecular biology that can be used very effectively in teaching new generations of geneticists. Mendel's characters also provide novel insights into the nature of the genes responsible for characteristics of agronomic and consumer importance.

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“…Seed shape (smooth versus wrinkled) and stem length are regulated by the R and Le loci and correspond to natural mutations of a starch-branching enzyme gene (13) and a gibberellin 3␤-hydroxylase gene (14,15), respectively. Cotyledon color (yellow versus green) is regulated by the I locus (16), with the i mutant retaining not only greenness of the cotyledon during seed maturation but also greenness of leaves during senescence, suggesting that this mutant is a stay-green mutant (17).…”

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Mendel's green cotyledon gene encodes a positive regulator of the chlorophyll-degrading pathway

Satō

Morita

Nishimura

et al. 2007

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

197

148

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Mutants that retain greenness of leaves during senescence are known as ''stay-green'' mutants. The most famous stay-green mutant is Mendel's green cotyledon pea, one of the mutants used in determining the law of genetics. Pea plants homozygous for this recessive mutation (known as i at present) retain greenness of the cotyledon during seed maturation and of leaves during senescence. We found tight linkage between the I locus and stay-green gene originally found in rice, SGR. Molecular analysis of three i alleles including one with no SGR expression confirmed that the I gene encodes SGR in pea. Functional analysis of sgr mutants in pea and rice further revealed that leaf functionality is lowered despite a high chlorophyll a (Chl a) and chlorophyll b (Chl b) content in the late stage of senescence, suggesting that SGR is primarily involved in Chl degradation. Consistent with this observation, a wide range of Chl-protein complexes, but not the ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit, were shown to be more stable in sgr than wild-type plants. The expression of OsCHL and NYC1, which encode the first enzymes in the degrading pathways of Chl a and Chl b, respectively, was not affected by sgr in rice. The results suggest that SGR might be involved in activation of the Chl-degrading pathway during leaf senescence through translational or posttranslational regulation of Chl-degrading enzymes.locus ͉ pea ͉ rice ͉ senescence ͉ stay green

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Mendel's Stem Length Gene (Le) Encodes a Gibberellin 3b-Hydroxylase

Cited by 54 publications

References 0 publications

The Pea DELLA Proteins LA and CRY Are Important Regulators of Gibberellin Synthesis and Root Growth

The Pea DELLA Proteins LA and CRY Are Important Regulators of Gibberellin Synthesis and Root Growth

Mendel’s Genes: Toward a Full Molecular Characterization

Mendel's green cotyledon gene encodes a positive regulator of the chlorophyll-degrading pathway

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