Expression of green fluorescent protein in pollen of oilseed rape (Brassica napus L.) and its utility for assessing pollen movement in the field

Transgene movement via pollen is an important component of gene flow from transgenic plants. Here, we present proof‐of‐concept studies that demonstrate the monitoring of short distant movement of pollen expressing a genetically encoded fluorescent tag in oilseed rape (Brassica napus L. cv. Westar). Transgenic oilseed rape plants were produced using Agrobacterium‐mediated transformation method with the pBINDC1 construct containing a green fluorescent protein (GFP) variant, mGFP5‐ER, under the control of the pollen‐specific LAT59 promoter from tomato. Transgenic pollen was differentiated from non‐transgenic pollen in vivo by a unique spectral signature, and was shown to be an effective tool to monitor pollen movement in the greenhouse and field. GFP‐tagged pollen also served as a practical marker to determine the zygosity of plants. In a greenhouse pollen flow study, more pollen was captured at closer distances from the source plant plot with consistent wind generated by a fan. Under field conditions, GFP transgenic pollen grains were detected up to a distance of 15 m, the farthest distance from source plants assayed. GFP‐tagged pollen was easily distinguishable from non‐transgenic pollen using an epifluorescence microscope.