Nectar is the sweet fluid that many dicotyledenous plants use to attract insect pollinators. In 1994, we discovered that the nectar of tobacco plants also contains a limited array of nectar proteins. These proteins are called Nectarins to indicate their source. We have isolated and characterized several of these proteins. The figure at right shows an SDS PAGE analysis of raw nectar proteins. This analysis identified at least four Nectarins, which we termed Nectarin I through Nectarin IV. A more careful analysis reveals that there are 10 to 12 proteins in these nectars.

Lane 1, Molecular Weight Standards; Lane 2, raw tobacco nectar; Lane 3, Western Blot of nectar proteins probed with anti-Nectarin I.

Nectarin I is the most abundant of the nectar proteins.
	Nectarin I Findings Nectarin I belongs to a family of proteins termed Germin-like Proteins (GLPs) The enzymatic activity associated with Nectarin I is Superoxide Dismutase Nectarin I is widely conserved among dicotyledenous plants
	References relating to Nectarin I  1 Carter, C., Graham, R. and Thornburg, R.W. (1999) Nectarin I is a novel, soluble germin-like protein expressed in the nectar of Nicotiana sp Plant Mol. Biol. 41:207-216.  2 Carter, C. and Thornburg, R.W. (2000) Tobacco Nectarin I: Purification and characterization as a germin-like, manganese superoxide dismutase implicated in the defense of floral reproductive tissues. J Biol Chem 275:36726-36733.
	The Nectarin I gene was recently isolated and characterized. It can be accessed from the GenBank. Also a number of closely related genes can also be accessed there. Nicotiana plumbaginifolia nectarin I precursor (NEC1) gene, complete cds Lycopersicon esculentum mRNA for germin-like protein, complete cds Arabidopsis thaliana germin-like protein 7 (GLP7) gene, complete cds Arabidopsis thaliana germin-like protein 1 (GLP1) gene, complete cds

Nectarin V
	Although Nectarin V has been characterized, it has not yet been published. Once the manuscript is accepted, a link to it will be available here.