title: Heterologous expression of the BABY BOOM AP2/ERF transcription factor enhances the regeneration capacity of tobacco (Nicotiana tabacum L.).
abstract: Gain-of-function studies have shown that ectopic expression of the BABY BOOM (BBM) AP2/ERF domain transcription factor is sufficient to induce spontaneous somatic embryogenesis in Arabidopsis (Arabidopsis thaliana (L.) Heynh) and Brassica napus (B. napus L.) seedlings. Here we examined the effect of ectopic BBM expression on the development and regenerative capacity of tobacco (Nicotiana tabacum L.) through heterologous expression of Arabidopsis and B. napus BBM genes. 35S::BBM tobacco lines exhibited a number of the phenotypes previously observed in 35S::BBM Arabidopsis and B. napus transgenics, including callus formation, leaf rumpling, and sterility, but they did not undergo spontaneous somatic embryogenesis. 35S::BBM plants with severe ectopic expression phenotypes could not be assessed for enhanced regeneration at the seedling stage due to complete male and female sterility of the primary transformants, therefore fertile BBM ectopic expression lines with strong misexpression phenotypes were generated by expressing a steroid-inducible, post-translationally controlled BBM fusion protein (BBM:GR) under the control of a 35S promoter. These lines exhibited spontaneous shoot and root formation, while somatic embryogenesis could be induced from in-vitro germinated seedling hypocotyls cultured on media supplemented with cytokinin. Together these results suggest that ectopic BBM expression in transgenic tobacco also activates cell proliferation pathways, but differences exist between Arabidopsis/B. napus and N. tabacum with respect to their competence to respond to the BBM signalling molecule.
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Appalachian Fruit Research Station, Kearneysville, WV 25430, USA. srinivas@afrs.ars.usda.gov
authors.forename: Chinnathambi
authors.initials: C
authors.lastname: Srinivasan
authors.forename: Zongrang
authors.initials: Z
authors.lastname: Liu
authors.forename: Iris
authors.initials: I
authors.lastname: Heidmann
authors.forename: Ence Darmo Jaya
authors.initials: ED
authors.lastname: Supena
authors.forename: Hiro
authors.initials: H
authors.lastname: Fukuoka
authors.forename: Ronny
authors.initials: R
authors.lastname: Joosen
authors.forename: Joep
authors.initials: J
authors.lastname: Lambalk
authors.forename: Gerco
authors.initials: G
authors.lastname: Angenent
authors.forename: Ralph
authors.initials: R
authors.lastname: Scorza
authors.forename: Jan B M
authors.initials: JB
authors.lastname: Custers
authors.forename: Kim
authors.initials: K
authors.lastname: Boutilier
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D029688:Brassica napus / Q000235:genetics; D015870:Gene Expression; D018515:Plant Leaves / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000033:anatomy & histology / Q000235:genetics* / Q000254:growth & development*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C518629:BABY BOOM protein, Arabidopsis; D014157:Transcription Factors