Maize Transformation Using the Morphogenic Genes Baby Boom and Wuschel2

2018 ◽  
pp. 81-93 ◽  
Author(s):  
Todd Jones ◽  
Keith Lowe ◽  
George Hoerster ◽  
Ajith Anand ◽  
Emily Wu ◽  
...  
Keyword(s):  
Baby Boom ◽  
Maize Transformation

scholarly journals An efficient gene excision system in maize

2020 ◽  
Author(s):  
Ning Wang ◽  
Maren Arling ◽  
George Hoerster ◽  
Larisa Ryan ◽  
Emily Wu ◽  
...  
Keyword(s):  
Baby Boom ◽  
Ectopic Expression ◽  
Culture Conditions ◽  
Early Embryo ◽  
Marker Genes ◽  
Developmentally Regulated ◽  
Maize Transformation ◽  
Efficient Gene ◽  
Transformation Methods ◽  
Gene Excision

ABSTRACTUse 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. In addition, altering the ectopic 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 53.3%-68.4%; however, the transformation frequency was lower (12.9%-49.9%). 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 (3.6%-14%), 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.

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

2020 ◽  
Vol 56 (3) ◽  
pp. 265-279 ◽  
Author(s):  
George Hoerster ◽  
Ning Wang ◽  
Larisa Ryan ◽  
Emily Wu ◽  
Ajith Anand ◽  
...  
Keyword(s):  
Somatic Embryo ◽  
High Frequency ◽  
Selectable Marker ◽  
Baby Boom ◽  
Marker Gene ◽  
Single Copy ◽  
System A ◽  
Maize Transformation ◽  
Embryo Formation ◽  
Wide Range

AbstractThe 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-Pltppro), 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.”

Le baby-boom de l'art

1991 ◽  
Vol 100 (1) ◽  
pp. 79-88
Author(s):  
Christian Ruby
Keyword(s):  
Baby Boom

Does the ageing population correctly predict the need for medical beds?: Part one: fundamental principles

2021 ◽  
Vol 27 (8) ◽  
pp. 1-10
Author(s):  
Rodney P Jones
Keyword(s):  
World War Ii ◽  
Capacity Planning ◽  
Baby Boom ◽  
National Average ◽  
Ageing Population ◽  
Bed Occupancy ◽  
World War ◽  
Funding Formula ◽  
Hospital Bed ◽  
The World

The World War II baby boom, coupled with increasing life expectancy, will lead to increasing numbers of deaths for the next 40 years. The last year of life represents a large proportion (55%) of lifetime hospital bed occupancy. This is called the nearness to death effect. However, the nearness to death effect has not been factored into NHS capacity planning, which largely relies on age-based forecasting, often called the ageing population. In certain locations, deaths are predicted to rise far more rapidly than the national average of 1% per annual growth. These locations are highly susceptible to capacity pressures emanating from the nearness to death effect, which is not compatible with recent policies that aim to build smaller hospitals. This article is the first of a two-part series discussing these trends in deaths and bed demand, as well as the likely impact on NHS capacity and the implications for the NHS funding formula.

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