A critical stage in pollen development is the dissolution of tetrads into free microspores. Tetrads are surrounded by a wall composed primarily of β-1,3-glucan. At the completion of meiosis, tetrads are released into the anther locule after hydrolysis of the callose by a β-1,3-glucanase complex. The cDNA corresponding to a β-1,3-glucanase cloned from tobacco (Tag 1) represents a gene that is highly similar to other β-1,3-glucanases and is expressed exclusively in anthers from the tetrad to free microspore stage of pollen development. Tag 1 protein was overexpressed in E. coli, accumulating in insoluble inclusion bodies. Polyclonal antibodies against Tag 1 recombinant protein identify a single 33 kD protein accumulating only in anthers at tetrad and free microspore stages where β-1,3-glucanase activity is present. Transgenic plants expressing Tag 1 antisense RNA were produced. Although Tag 1 RNA and protein levels were greatly reduced, tetrad dissolution and pollen development were normal. These data indicate that under the conditions these tobacco plants were grown, wild type levels of Tag 1 protein are not necessary for male fertility.
Bibliographical noteFunding Information:
* E-mail corresponding author: firstname.lastname@example.org a This research was supported in part by the Minnesota Agricultural Experiment Station. Paper No.021210115.
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- Pollen development