β-Glucuronidase gene and green fluorescent protein gene expression in de-exined pollen of Nicotiana tabacum by microprojectile bombardment

Abstract

Gene constructs containing the β-glucuronidase (GUS) gene or green fluorescent protein (GFP) gene under the control of pollen-specific promoter Zm13-260 from maize were introduced by particle bombardment into de-exined pollen of Nicotiana tabacum. The de-exined pollen exhibited transient expression of the GUS or GFP gene as indicated by histochemical and fluorescent assay, respectively. The frequency of de-exined pollen transformation with the GUS or GFP gene was approximately 6 and 3 times higher, respectively, than that of pollen with intact walls, indicating that pollen deprived of the exine barrier responded better to foreign gene transfer than did the original. Cytological observation of GUS-expressing pollen grains showed that introduced gold particles were visible in the cytoplasm and vegetative nucleus as well as in the generative nucleus. GFP-expressing pollen tubes were observed in the style even after pollination.