Production of hybrid cells from single protoplasts of sunflower hypocotyl and broad bean guard cells by electrical fusion

The C4-directed enzymatic apparatus in guard cells is known to be coupled w ith a reduction in photorespiration resulting in a higher survival rate and yield potential of crops. This has led to searches for guard-cell-specific genes and promoters and methods for transferring them into C3-plants. To e xplore this possibility we performed somatic fusions between guard cell pro toplasts from Vicia faba and hypocotyl protoplasts from Helianthus annuus, using a technique which allows fusion of a single pair of individually sele cted protoplasts. We obtained fusions in 30-70% of attempts. Culture of the hybrid fusion products in a liquid nutrient medium, without conditioning o r feeder cells, produced microcolonies consisting of 8-9 cells within 9 day s of culture.