Localization of transcripts corresponding to the major allergen from olivepollen (Ole e I) by electron microscopic non-radioactive in situ RT-PCR

In situ reverse transcription-PCR of mRNAs corresponding to the olive major allergen (Ole e I) has been tested at the ultrastructural level in mature olive pollen. The transcripts were present in the cytoplasm of both the veg etative and the generative cells, frequently associated to ribosomes in the endoplasmic reticulum. No labeling was detected in the pollen wall, nor in vacuoles, lipid bodies, plastids or mitochondria. Localization of the majo r olive allergen at ultrastructural level showed the protein present mainly in the lumen of the. endoplasmic reticulum vesicles or pockets scattered i n the cytoplasm, and in the outer region of the pollen exine. The results c onfirm the rough endoplasmic reticulum as the cell system involved in both the synthesis and storage of this protein. This is the first report of in s itu RT-PCR on plant material at the ultrastructural level. The method descr ibed for mRNA amplification and detection is, confirmed as a valuable tool for studying gene expression in plant material, (C) 2001 Elsevier Science L td. All rights reserved.