Immature tassels as alternative explants in somatic embryogenesis and plant regeneration in south Brazilian maize genotypes

Grando, Magali Ferrari; Varnier, Madelaine Lurdes; Silva, Marilia Rodrigues de; Marti, Beatriz; Pereira, L. R.; Suzin, Marilei

doi:10.4025/actasciagron.v35i1.15545

Cited by 8 publications

(8 citation statements)

References 35 publications

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“…Plant regeneration has also been reported from calli initiated from different explants, namely, anthers [2][3][4], glumes [5], immature inflorescence [6], immature tassels [7][8][9], leaf segments [10][11][12], protoplasts [13], seedling segments [14][15][16], shoot tips [17][18][19], shoot apical meristem [20], mature embryos [15,21,22], and immature embryos [23][24][25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Coleoptilar node - A season-independent explant source for in vitro culture in maize (Zea mays L.)

2018

J App Biol Biotech

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In vitro plant regeneration is preliminary requisite in the process of obtaining transgenic plants. Somatic embryogenesis is the most frequently used method of in vitro plant regeneration in maize. In this study, a reliable and reproducible maize regeneration method has been standardized using mature embryos. Inspite, the immature embryos are most suitable explants for somatic embryogenesis, obtaining these explants continuously is a laborious and tedious process, especially in summer. Hence, alternate explants of maize for in vitro regeneration have been chosen from different parts of embryonic axis. This study provides an evaluation of inbred lines and effect of hormonal combinations on total and embryogenic callus induction, their growth rate, and plantlet regeneration. Coleoptilar nodal explants from four inbred lines were cultured on different concentrations and combinations of 2,4-dichloro phenoxyacetic acid (2,4-D) along with kinetin (Kn). Explants grown on Murashige and Skoog medium supplemented with 2,4-D and Kn at a concentration of 5 and 1 mg/L, respectively, were found to be the best one for yielding a high frequency of embryogenic callus. Inbred line, NM81A was found to be the best one for in vitro culture among the four lines used. Combination of 6-benzylaminopurine and Kn at a concentration of 1 mg/L each promoted the highest frequency of shoot induction.

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Section: Introductionmentioning

confidence: 99%

Coleoptilar node - A season-independent explant source for in vitro culture in maize (Zea mays L.)

2018

J App Biol Biotech

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“…However, the Hi-II hybrid presents poor agronomic performance (Ishida et al, 2007;Que et al, 2014). The use of a genotype showing good in vitro cultivation response and good agronomic characteristics, such as the BR 451 (Grando et al, 2013;Petrillo et al, 2008), accelerates commercial transgenic plant production, since the gene inserted in the transgenic event can be transferred to elite lines without the transfer of additional unwanted traits. Therefore, improvement in the genetic transformation of BR 451 opens the possibility of implementing its use in genetic engineering.…”

Section: Resultsmentioning

confidence: 99%

<b>Increased transient genetic transformation <i>in immature</i> embryos of Brazilian BR 451 maize co-cultivated with <i>Agrobacterium tumefaciens

et al. 2018

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ABSTRACT. Genetic engineering has amplified the possibilities of crop breeding and supported sustainability ideals. Agrobacterium tumefaciens is the preferred transformation system, since it produces transgenic plants with more stable transgene expression and inheritance. The agrobacteria and plant tissue must be co-cultivated in conditions that allow gene transfer. This study aimed to evaluate how cocultivation time and temperature affect the transformation of immature maize embryos of the Hi-II hybrid (model genotype) and the Brazilian BR 451 variety with A. tumefaciens EHA101:pTF102. The pTF102 plasmid carries a uidA reporter gene that enables transient transformation to be quickly verified by GUS histochemical assays. Increasing the co-cultivation period from three to five days at 20°C resulted in a higher number of GUS positive embryos and blue spots per embryo in the BR 451 Brazilian variety, indicating better bacterial T-DNA transfer into the target explant cells. This condition raised the BR 451 response level to match the response level of the Hi-II control genotype, indicating that this Brazilian variety is suitable for genetic transformation.Keywords: agrobacteria; GUS histochemical assay; genetic engineering; Zea mays.Aumento da transformação genética transiente em embriões imaturos do genótipo brasileiro de milho BR 451 co-cultivados com Agrobacterium tumefaciens RESUMO. A engenharia genética ampliou as possibilidades do melhoramento genético vegetal, apoiando ideais de sustentabilidade. A Agrobacterium tumefaciens é o sistema de transformação preferido, uma vez que permite a produção de plantas transgênicas com maior estabilidade na expressão gênica e na herdabilidade. A Agrobactéria e o tecido vegetal devem ser co-cultivados em condições que permitam a transferência de genes. Este estudo teve como objetivo avaliar como o tempo e a temperatura durante o co-cultivo afetam a transformação de embriões imaturos de milho do híbrido Hi-II (genótipo modelo) e da variedade brasileira BR 451 com A. tumefaciens EHA101:pTF102. O plasmídeo pTF102 carrega o gene repórter uidA permitindo que a transformação transiente seja prontamente verificada pelo ensaio histoquímico de GUS. O aumento do período de co-cultivo de três para cinco dias a 20°C resultou num maior número de embriões GUS positivos e maior número de pontos azuis por embrião na variedade brasileira BR 451, indicando uma melhor transferência do T-DNA da bactéria para as células do explante alvo. Esta condição elevou o nível de resposta da BR 451 chegando a coincidir com o nível de resposta do controle Hi-II, indicando que esta variedade brasileira é adequada para transformação genética.Palavras-chave: agrobactéria; ensaio histoquímico de GUS; engenharia genética; Zea mays.

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“…BR 451 mature variety (1-2mm) embryos were cultured in the callus-induction medium according to GRANDO et al, (2013) until the embryogenic calli were formed. Ten subcultures later, the calluses were used for plant regeneration, which involved three stages: (a) germination of the somatic embryos and shoot formation; (b) shoot development and (c) rooting and seedling.…”

Section: Regeneration Of the Br 451 Maize Plantsmentioning

confidence: 99%

“…Great efforts have been made to adapt gene transfer into cereals via A. tumefaciens as they are resistant to such maneuvers (FRAME et al, 2002;2011). This recalcitrance is related to two different aspects: a) the low in vitro response (CARVALHO et al, 1997;FRAME et al, 2006;GONZÁLES et al, 2012;GRANDO et al, 2013) e b) low explant sensibility to agrobacteria infection (VENNA et al, 2003;CARVALHO et al, 2004;WANG et al, 2007), thus restricting the number of transformed maize genotypes (GONZÁLEZ et al, 2012;OMBORI et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

Genetic transformation of the Brazilian BR 451 maize variety by the Agrobacterium tumefaciens method

et al. 2017

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The asexually gene introduction by genetic engineering has brought enormous possibilities to innovate plant breeding. However, principally because of the low in vitro response, genetic transformation has been restricted to only certain genotypes of agronomically significant species. With the objective of establishing a protocol for genetically transforming the Brazilian BR 451 maize variety through Agrobacterium tumefaciens, it was studied the capacity of plant regeneration in vitro from embryogenic calli cultivated in three regeneration media, each having different growth regulators. It was also evaluated the temperature stress effect on the transformation of the immature embryos with A. tumefaciens EHA 101 containing the plasmid pTF102 with uidA and bar genes. The BR 451 variety embryos and those of the Hi-II hybrid (control) were exposed to three treatments applied as they were being infected with the agrobacteria (a) infection at 25°C; (b) infection at 40°C; (c) pretreatment at 40°C for 5 seconds followed by infection at 25°C. Transformation was determined by uidA gene expression and through the callus resistant to the herbicide Bialaphos® formation. Embryos infected at 40°C showed a higher degree of genetic transformation in the Hi-II, although the same was not noted in BR 451. When growth regulators were added to the culture medium the number of regenerated BR 451 plants showed no increase.

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Immature tassels as alternative explants in somatic embryogenesis and plant regeneration in south Brazilian maize genotypes

Cited by 8 publications

References 35 publications

Coleoptilar node - A season-independent explant source for in vitro culture in maize (Zea mays L.)

Coleoptilar node - A season-independent explant source for in vitro culture in maize (Zea mays L.)

<b>Increased transient genetic transformation <i>in immature</i> embryos of Brazilian BR 451 maize co-cultivated with <i>Agrobacterium tumefaciens

Genetic transformation of the Brazilian BR 451 maize variety by the Agrobacterium tumefaciens method

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