Response of 98140 Corn With <i>Gat4621</i> and <i>hra</i> Transgenes to Glyphosate and ALS-Inhibiting Herbicides

Green, Jerry M.; Hale, Theresa; Pagano, Margaret A.; Andreassi, John L.; Gutteridge, Steven

doi:10.1614/ws-08-152.1

Cited by 26 publications

(19 citation statements)

References 17 publications

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“…Agrobacterium with different T-DNAs in the binary plasmid are referred to as "strains." Two selectable markers were used in experiments: a sulfonylurea herbicide resistance marker 'Hra' (Green et al 2009), driven by the sorghum ALS promoter (see Supplemental Table S-2), was used for selection with 0.1 mg L −1 imazapyr in both the maturation and rooting medium, or the Ubi pro ::NPTII gene was used with 150 mg L −1 G418 in both the maturation and rooting medium (13329 and 13158 media, respectively). Constructs used in this study are shown in Figs.…”

Section: Methodsmentioning

confidence: 99%

Use of non-integrating Zm-Wus2 vectors to enhance maize transformation

Hoerster

Wang

Ryan

et al. 2020

In Vitro Cell.Dev.Biol.-Plant

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The use of Baby boom (Bbm) and Wuschel2 (Wus2) has made maize transformation more efficient across an increasingly wide range of inbreds. However, the benefits have come with the requirement of excising these transformation helper components to enable plant regeneration, which adds size to the T-DNA, and complexity to the transformation system. A new system with the advantages of smaller size and simplicity for the selectable marker gene-containing T-DNA is described. First, expression of Zm-Wus2 alone driven by the maize Pltp promoter (Zm-Pltp pro), was determined to be sufficient to induce rapid somatic embryo formation from the scutella of maize immature embryos. It was also demonstrated that co-infecting with two strains of Agrobacterium, one with a Wus2 expression cassette, and the other with a combination of both selectable and visual marker cassettes, produced transformed T0 plants that contained only a single copy of the selectable marker T-DNA, without the integration of Wus2. Furthermore, the process was optimized by varying the ratio of the two Agrobacterium strains, and by modulating Wus2 expression to enable high-frequency recovery of selectable marker-containing T0 plants that did not contain Wus2. Several factors may have contributed to this outcome. Wus2 expression in localized cell(s) appeared to stimulate somatic embryogenesis in neighboring cells, including those that had integrated the selectable marker. In addition, in cells in which the Wus2 T-DNA did not integrate but the selectable marker T-DNA did, transient Wus2 expression stimulated somatic embryo formation and regeneration of stable T0 plants that contained the selectable marker. In addition, augmenting the Pltp promoter with three viral enhancer elements to increase Wus2 expression stimulated embryogenesis while precluding their regeneration. The phenomenon has now been designated as "altruistic transformation."

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Section: Methodsmentioning

confidence: 99%

Use of non-integrating Zm-Wus2 vectors to enhance maize transformation

Hoerster

Wang

Ryan

et al. 2020

In Vitro Cell.Dev.Biol.-Plant

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“…The conditions for Agrobacterium suspension culture preparation following embryo isolation and infection have been previously described ( Lowe et al., 2018 ; Hoerster et al., 2020 ). Two selectable markers were used in experiments: HRA ( Green et al., 2009 ), a sulfonylurea herbicide resistance marker, driven by the sorghum Als promoter for selection with 0.1 mg/L imazapyr in culture medium, or the Ubi pro : NPTII gene for selection with 150 mg/L G418 in culture medium.…”

Section: Methodsmentioning

confidence: 99%

An Efficient Gene Excision System in Maize

et al. 2020

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Use of the morphogenic genes Baby Boom ( Bbm ) and Wuschel2 ( Wus2 ), along with new ternary constructs, has increased the genotype range and the type of explants that can be used for maize transformation. Further optimizing the expression pattern for Bbm / Wus2 has resulted in rapid maize transformation methods that are faster and applicable to a broader range of inbreds. However, expression of Bbm / Wus2 can compromise the quality of regenerated plants, leading to sterility. We reasoned excising morphogenic genes after transformation but before regeneration would increase production of fertile T0 plants. We developed a method that uses an inducible site-specific recombinase ( Cre ) to excise morphogenic genes. The use of developmentally regulated promoters, such as Ole , Glb1 , End2 , and Ltp2 , to drive Cre enabled excision of morphogenic genes in early embryo development and produced excised events at a rate of 25–100%. A different strategy utilizing an excision-activated selectable marker produced excised events at a rate of 53–68%; however, the transformation frequency was lower (13–50%). The use of inducible heat shock promoters (e.g. Hsp17.7 , Hsp26 ) to express Cre, along with improvements in tissue culture conditions and construct design, resulted in high frequencies of T0 transformation (29–69%), excision (50–97%), usable quality events (4–15%), and few escapes (non-transgenic; 14–17%) in three elite maize inbreds. Transgenic events produced by this method are free of morphogenic and marker genes.

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“…For new GM soybean, 2,4-D and dicamba resistance traits will always be used in stacks with at least one other herbicide-resistant trait. Glyphosate and ALS trait stack, recently deregulated in the US, possibly will allow the use of ALS-inhibiting herbicides with soil residual that are too phytotoxic to use on conventional crop cultivars [24]. In reference [25], diversification may make weed management more complex, but growers must not use new GM crop resistant to herbicides in the same way that some used initial GM crops, in order to rely only on one herbicide until it is no longer effective and then switch herbicides.…”

Section: Issues On Weed Managementmentioning

confidence: 99%