Morphotypes of friable embryogenic maize callus

Welter, Mary E.; Clayton, Derek; Miller, Matt; Petolino, J. E

doi:10.1007/bf00232656

Cited by 25 publications

(11 citation statements)

References 6 publications

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“…Vain et al (1989) demonstrated that 5-10 mg l -1 AgNO 3 enhanced the induction of type-II callus from immature embryos of the maize line A188. A positive response was observed within a range of 1.8-18 mg l -1 for inbred line B73 and its derivatives (Songstad et al 1991;Welter et al 1995). Even though a few tropical maize genotypes have shown the capacity to produce type-II callus, this was improved by the addition of 15 mg l -1 AgNO 3 (Bohorova et al 1995;Carvalho et al 1997).…”

Section: Callus Inductionmentioning

confidence: 90%

“…Induction and maintenance of embryogenic-callus from immature embryos were evaluated based on the previously described N6C1 medium (Bohorova et al 1995), which consisted of N6 basal medium (Chu et al 1975) supplemented with 200 mg l -1 casein hydrolysate, 2.302 mg l -1 L-proline, 3% sucrose and 2 mg l -1 Dicamba; addition of three doses of AgNO 3 at 10 (N6C1-10), 15 (N6C1-15) and 20 mg l -1 (N6C1-20) into the base N6C1 medium, were evaluated for its ability to induce embryogenic type-II callus from the embryo-scutellum as has already been demonstrated on several tropical maize lines (Vain et al 1989;Welter et al 1995;Carvalho et al 1997). For callus initiation and maintenance, immature embryos were cultured oriented with the embryo-axis side in contact with the medium (scutellum side up) and incubated in the darkness at 27°C; embryogenic tissue was subcultured to fresh medium every 20 days.…”

Section: Induction and Maintenance Of Calli And Plant Regenerationmentioning

confidence: 99%

“…In this sense the maize embryoscutellum having a lot of competent cells for somatic embryogenesis, is a proved primary explant from which fertile plants can be regenerated at high frequency (Carvalho et al 1997;Brettschneider et al 1997;Rascón-Cruz et al 2004), and has been selected as a target tissue for transformation by electroporation (D'Halluin et al 1992) and biolistic (Fromm et al 1990;Gordon-Kamm et al 1990;Brettschneider et al 1997). The fact that in maize embryos infected with A. tumefaciens transformation mainly occurs in host cells belonging to the embryo axis side and the apical end (Frame et al 2002), and non-embryogenic calli emerged from these, this is an obstacle for reaching efficient rates of transformed embryogenic-calli generation (Welter et al 1995).…”

Section: Introductionmentioning

confidence: 99%

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A transgenic tropical maize line generated by the direct transformation of the embryo-scutellum by A. tumefaciens

Valdéz-Ortiz

Medina‐Godoy²,

Valverde

et al. 2007

Plant Cell Tiss Organ Cult

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An efficient Agrobacterium-mediated transformation system, from which transgenic tropical maize plants were directly generated without previous crosses with laboratory or temperate lines, was established. Experimental evaluations were focused on two main issues: (i) establishment of appropriate tissue culture conditions, which induced somatic embryogenesis from the scutellum-cells, and (ii) the delivery of T-DNA toward these cells. High rates of embryogenic-calli, mainly generated from the embryo-scutellum, were obtained when 15 mg l -1 AgNO 3 were included into the N6-based induction medium; rates up to 19 plants per gram were regenerated from these induced calli. Regarding the Agrobacterium strains evaluated for their transformation capability on the tropical maize line LPC13 used here, best results were obtained from the EHA105 cells when applied at OD 550 nm = 0.5-1.0. Physical microwounds before the Agro-infection proved to be an excellent way to promoting both the T-DNA transferring toward the embryo-scutellum and the increasing of rates of transient GUS expression. The highest frequencies of transient GUS expression corresponding to the scutellum-cells as well as the regeneration of whole transgenic plants emerged from them, were obtained using immature embryos wounded by bombarding at 80 lb/in 2 followed for vacuum infiltration before and during the Agro-infection, respectively, or using embryos wounded by 5 s-sonication (without vacuum infiltration) before the Agro-infection. Transformation frequencies up to 5.41% and 6.82% were obtained from the Agro-infected embryos wounded by particle-bombardment and sonication, respectively. Analyses of the progenies confirmed the sexual transmission of the introduced genes and their stable expression.

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Section: Callus Inductionmentioning

confidence: 90%

Section: Induction and Maintenance Of Calli And Plant Regenerationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A transgenic tropical maize line generated by the direct transformation of the embryo-scutellum by A. tumefaciens

Valdéz-Ortiz

Medina‐Godoy²,

Valverde

et al. 2007

Plant Cell Tiss Organ Cult

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“…Only the Type II embryogenic callus (EC) is highly regenerative (Burris et al 2009). This phenomenon was also found on other monocots, such as maize (Armstrong and Green 1985;Vasil and Vasil 1994;Welter et al 1995), rice (Rueb et al 1994), sugarcane (Guiderdoni and Demarly 1988), wheat (Parmar et al 2012), and various non-food grasses (Lu and Vasil 1981;Zhang et al 2007;Li and Qu 2011). In general, two types of calluses had been classified and described depending on color, regeneration ability and texture.…”

mentioning

confidence: 93%

Inside out: high-efficiency plant regeneration and Agrobacterium-mediated transformation of upland and lowland switchgrass cultivars

et al. 2015

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Selection of pre-embryogenic callus from a core structure from mature seed-derived callus is the key for high-efficiency plant regeneration and transformation of switchgrass different cultivars. Switchgrass (Panicum virgatum L.) has been identified as a dedicated biofuel crop. For its trait improvement through biotechnological approaches, we have developed a highly efficient plant regeneration and genetic transformation protocol for both lowland and upland cultivars. We identified and separated a pre-embryogenic "core" structure from the seed-derived callus, which often leads to development of highly regenerative type II calluses. From the type II callus, plant regeneration rate of lowland cultivars Alamo and Performer reaches 95%, and upland cultivars Blackwell and Dacotah, 50 and 76%, respectively. The type II callus was also amenable for Agrobacterium-mediated transformation. Transformation efficiency of 72.8% was achieved for lowland cultivar Alamo, and 8.0% for upland cultivar Dacotah. PCR, Southern blot and GUS staining assays were performed to verify the transgenic events. High regenerative callus lines could be established in 3 months, and transgenic plants could be obtained in 2 months after Agrobacterium infection. To our knowledge, this is the first report on successful plant regeneration and recovery of transgenic plants from upland switchgrass cultivars by Agrobacterium-mediated transformation. The method presented here could be helpful in breaking through the bottleneck of regeneration and transformation of lowland and upland switchgrass cultivars and probably other recalcitrant grass crops.

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“…The morphology of callus has been reported and described in the important agronomic monocot crops such as maize [8][9][10][11][12][13][14], rice [15][16][17], sorghum [18], sugarcane [19], wheat [20], and various nonfood grasses [21][22][23][24][25][26]. Type I callus is the typical and most prevalent callus formed in monocot species.…”

Section: Introductionmentioning

confidence: 99%

An Improved Tissue Culture System for Embryogenic Callus Production and Plant Regeneration in Switchgrass (Panicum virgatum L.)

et al. 2009

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The increased emphasis on research of dedicated biomass and biofuel crops begs for biotechnology method improvements. For switchgrass (Panicum virgatum L.), one limitation is inefficient tissue culture and transformation systems. The objectives of this study were to investigate the utility of a new medium described here, LP9, for the production and maintenance of switchgrass callus and its regeneration, which also enables genetic transformation. LP9 medium is not based on Murashige and Skoog (MS) medium, the basal medium that all published switchgrass transformation has been performed. We demonstrate an efficient tissue culture system for switchgrass Alamo 2, which yields increased viability of callus and the ability to maintain callus for a duration of over 6 months. This longevity gives a greater useful callus lifetime than for published switchgrass MS-based media. This increased longevity enables greater potential efficiency and throughput for a transformation pipeline. Callus produced on LP9 is categorized as type II callus, which is more friable and easier to multiply, maintain and transfer than type I callus obtained from previously described tissue culture systems.

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Morphotypes of friable embryogenic maize callus

Cited by 25 publications

References 6 publications

A transgenic tropical maize line generated by the direct transformation of the embryo-scutellum by A. tumefaciens

A transgenic tropical maize line generated by the direct transformation of the embryo-scutellum by A. tumefaciens

Inside out: high-efficiency plant regeneration and Agrobacterium-mediated transformation of upland and lowland switchgrass cultivars

An Improved Tissue Culture System for Embryogenic Callus Production and Plant Regeneration in Switchgrass (Panicum virgatum L.)

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