Infrequent transposition of Ac in lettuce, Lactuca sativa

Yang, Chin-Ying; Ellis, Jeff; Michelmore, Richard W.

doi:10.1007/bf00027366

Cited by 22 publications

(8 citation statements)

References 43 publications

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“…The higher activity in L. japonicus compared to Arabidopsis is also indicated by the appearance of fully green germline excisions already in the T2 progeny. In comparison to Arabidopsis [ 12], flax with 1 active line out of 35 [ 15] and lettuce where no Ac activity was detected in 32 lines [36], the activity in L. japonicus is very reasonable. In tobacco 9 of 17 lines showed Ac activity and fully green seedlings were appearing in the T2 [24].…”

Section: Discussionmentioning

confidence: 98%

The maize transposable element Ac is mobile in the legume Lotus japonicus

et al. 1995

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To evaluate the prospects for transposon mutagenesis in the autogamous diploid legume Lotus japonicus, the behaviour of the maize transposable element Ac was analysed in the progeny of 38 independent transgenic plants. The conditions for monitoring donor site excision using histochemical localization of beta-glucuronidase activity or the alternative spectinomycin resistance assay were established, and used to follow Ac mobility through two generations. Somatic excision was monitored as variegated cotyledons in the T2 generation and germinal excision events were scored in segregating T3 families as complete beta-glucuronidase-mediated staining of cotyledons or as a fully green spectinomycin-resistant phenotype. Using these assays an average germinal excision frequency of 12% was estimated in the T3 offspring from variegated plants. The fidelity of the excision assays was ascertained by comparing the frequency of germinal excision to the frequency of Ac reinsertion at new positions of the genome. Transposition of Ac in 42% of the plants and detection of the characteristic Ac insertion/excision footprints suggests that insertion mutagenesis with the autonomous maize Activator element is feasible in Lotus japonicus. Parameters influencing Ac behaviour, such as dosage, position effects and modification of the element itself, were also investigated comparing homozygous and hemizygous plants from the same family and by analysing different transformants.

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Section: Discussionmentioning

confidence: 98%

The maize transposable element Ac is mobile in the legume Lotus japonicus

et al. 1995

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“…Lettuce is amenable to most in vitro culture techniques and is easy to transform via Agrobacterium tumefaciens (Michelmore et al, 1987;Chupeau et al, 1994;Mazier et al, 2004;Lelivelt et al, 2005). Interestingly, Yang et al (1993aYang et al ( , 1993b already tested transposon mutagenesis using the well-known DNA transposable activator/dissociation (Ac/Ds) elements from maize (Zea mays) in lettuce. Despite demonstrating that the elements were functional in this plant, these authors showed that the frequency of germinal transposition provided was too low for practical use.…”

mentioning

confidence: 99%

Successful Gene Tagging in Lettuce Using the Tnt1 Retrotransposon from Tobacco

Mazier¹,

Botton²,

Flamain³

et al. 2007

Plant Physiol.

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The tobacco (Nicotiana tabacum) element Tnt1 is one of the few identified active retrotransposons in plants. These elements possess unique properties that make them ideal genetic tools for gene tagging. Here, we demonstrate the feasibility of gene tagging using the retrotransposon Tnt1 in lettuce (Lactuca sativa), which is the largest genome tested for retrotransposon mutagenesis so far. Of 10 different transgenic bushes carrying a complete Tnt1 containing T-DNA, eight contained multiple transposed copies of Tnt1. The number of transposed copies of the element per plant was particularly high, the smallest number being 28. Tnt1 transposition in lettuce can be induced by a very simple in vitro culture protocol. Tnt1 insertions were stable in the progeny of the primary transformants and could be segregated genetically. Characterization of the sequences flanking some insertion sites revealed that Tnt1 often inserted into genes. The progeny of some primary transformants showed phenotypic alterations due to recessive mutations. One of these mutations was due to Tnt1 insertion in the gibberellin 3b-hydroxylase gene. Taken together, these results indicate that Tnt1 is a powerful tool for insertion mutagenesis especially in plants with a large genome.

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“…Experiments with transposon tagging utilizing the Ac and Ds generated recessive transgenic mutants in which a dwarf phenotype with abnormal root and shoot development and the loss of Dm3 specificity cosegregated with the T-DNAs [37, 46]. However, the low frequency of Ac transposition in lettuce [47] determined that map-based cloning was a more successful approach to cloning Dm3 gene. The tobacco ( Nicotiana tabacum ) element Tnt1, one of the few identified active retrotransposons in plants, was used successfully for gene tagging in lettuce [48].…”

Section: Unconventional Ways To Generate Mutantsmentioning

confidence: 99%

Mutations in Lettuce Improvement

Mou

2011

International Journal of Plant Genomics

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Lettuce is a major vegetable in western countries. Mutations generated genetic variations and played an important role in the domestication of the crop. Many traits derived from natural and induced mutations, such as dwarfing, early flowering, male sterility, and chlorophyll deficiency, are useful in physiological and genetic studies. Mutants were also used to develop new lettuce products including miniature and herbicide-tolerant cultivars. Mutant analysis was critical in lettuce genomic studies including identification and cloning of disease-resistance genes. Mutagenesis combined with genomic technology may provide powerful tools for the discovery of novel gene alleles. In addition to radiation and chemical mutagens, unconventional approaches such as tissue or protoplast culture, transposable elements, and space flights have been utilized to generate mutants in lettuce. Since mutation breeding is considered nontransgenic, it is more acceptable to consumers and will be explored more in the future for lettuce improvement.

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Infrequent transposition of Ac in lettuce, Lactuca sativa

Cited by 22 publications

References 43 publications

The maize transposable element Ac is mobile in the legume Lotus japonicus

The maize transposable element Ac is mobile in the legume Lotus japonicus

Successful Gene Tagging in Lettuce Using the Tnt1 Retrotransposon from Tobacco

Mutations in Lettuce Improvement

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