NtWBC1, an ABC transporter gene specifically expressed in tobacco reproductive organs.
To identify genes specifically or predominantly expressed in the stigmas/styles and to establish their possible function in the reproductive process of plants, a tobacco stigma/style cDNA library was constructed and differentially screened, resulting in the isolation of several cDNA clones. The molecular characterization of one of these clones is described here. After sequencing the cDNA and the isolated genomic clone, it was determined that the corresponding gene encodes a protein containing an ATP-binding cassette, characteristic of ABC transporters. This gene, designated as NtWBC1 (Nicotiana tabacum ABC transporter of the White-Brown Complex subfamily), encodes a protein that contains the typical structure of the 'half-transporters' of the White subfamily. To establish the spatial expression pattern of the NtWBC1 gene, northern blot and real-time RT-PCR analyses with total RNA from roots, stems, leaves, sepals, petals, stamens, stigmas/styles, ovaries, and seeds were performed. The result revealed a transcript of 2.5 kb present at high levels in stigmas and styles and a smaller transcript (2.3 kb) present at a lower level in stamens. NtWBC1 expression is developmentally regulated in stigmas/styles, with mRNA accumulation increasing toward anthesis. In situ hybridization experiments demonstrated that NtWBC1 is expressed in the stigmatic secretory zone and in anthers, at the stomium region and at the vascular bundle. NtWBC1 is the first ABC transporter gene with specific expression in plant reproductive organs to be identified and its expression pattern suggests important role(s) in the reproductive process.
Otsu
Claudia Tomiko
CT
Depto. Biologia FFCLRP/Universidade de São Paulo, Av. Bandeirantes, 3900 Ribeirão Preto, SP 14040-901, Brazil.
daSilva
Idalete
I
de Molfetta
Jeanne Blanco
JB
da Silva
Lara Regina
LR
de Almeida-Engler
Janice
J
Engler
Gilbert
G
Torraca
Paulo Cesar
PC
Goldman
Gustavo Henrique
GH
Goldman
Maria Helena S
MH
D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D018745:Genome, Plant; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000235:genetics*; D012098:Reproduction; D016415:Sequence Alignment; D014026:Nicotiana / Q000235:genetics* / Q000378:metabolism
D018528:ATP-Binding Cassette Transporters; D010940:Plant Proteins