title: Low frequency paternal transmission of plastid genes in Brassicaceae.
abstract: Plastid-encoded genes are maternally inherited in most plant species. Transgenes located on the plastid genome are thus within a natural confinement system, preventing their distribution via pollen. However, a low-frequency leakage of plastids via pollen seems to be universal in plants. Here we report that a very low-level paternal inheritance in Arabidopsis thaliana occurs under field conditions. As pollen donor an Arabidopsis accession (Ler-Ely) was used, which carried a plastid-localized atrazine resistance due to a point mutation in the psbA gene. The frequency of pollen transmission into F1 plants, based on their ability to express the atrazine resistance was 1.9 × 10(-5). We extended our analysis to another cruciferous species, the world-wide cultivated crop Brassica napus. First, we isolated a fertile and stable plastid transformant (T36) in a commercial cultivar of B. napus (cv Drakkar). In T36 the aadA and the bar genes were integrated in the inverted repeat region of the B. napus plastid DNA following particle bombardment of hypocotyl segments. Southern blot analysis confirmed transgene integration and homoplasmy of plastid DNA. Line T36 expressed Basta resistance from the inserted bar gene and this trait was used to estimate the frequency of pollen transmission into F1 plants. A frequency of <2.6 × 10(-5) was determined in the greenhouse. Taken together, our data show a very low rate of paternal plastid transmission in Brassicacea. Moreover, the establishment of plastid transformation in B. napus facilitates a safe use of this important crop plant for plant biotechnology.
authors.affiliation: Molekularbiologie der Pflanzen (Botanik), Department Biologie I, Ludwig-Maximilians-Universität München, Großhaderner Str. 2-4, 82152, Martinsried, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Schneider
authors.forename: Christian
authors.initials: C
authors.lastname: Stelljes
authors.forename: Caroline
authors.initials: C
authors.lastname: Adams
authors.forename: Stefan
authors.initials: S
authors.lastname: Kirchner
authors.forename: Gabi
authors.initials: G
authors.lastname: Burkhard
authors.forename: Sabine
authors.initials: S
authors.lastname: Jarzombski
authors.forename: Inge
authors.initials: I
authors.lastname: Broer
authors.forename: Patricia
authors.initials: P
authors.lastname: Horn
authors.forename: Ashraf
authors.initials: A
authors.lastname: Elsayed
authors.forename: Peter
authors.initials: P
authors.lastname: Hagl
authors.forename: Dario
authors.initials: D
authors.lastname: Leister
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Koop
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D001280:Atrazine / Q000494:pharmacology; D029688:Brassica napus / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005818:Genetic Engineering; D010641:Phenotype; D045332:Photosystem II Protein Complex / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics*; D018087:Plastids / Q000235:genetics* / Q000378:metabolism; D011058:Pollen / Q000235:genetics / Q000254:growth & development; D019076:Transgenes
chemical_list: D045332:Photosystem II Protein Complex; C422369:photosystem II, psbA subunit; D001280:Atrazine