A highly efficient transform system for pear (<i>Pyrus pyrifolia</i>) through gene delivery to pollen

Utilizing pollen as a transgenic vector in agriculture has been markedly unsuccessful, particularly for fruit trees of the Rosaceae family. We chose a widely cultivated pear variety, 'Wonhwang' (<italic>Pyrus pyrifolia</italic> Nakai. cv. Wonhwang), which has been successfully used to transfer genes into mature pollen within just 4 min under negative pressure (−80 kPa). Despite irregular pollen morphology, the viability of this pear variety remained unaffected. Pollen carrying the green fluorescent protein (GFP) gene can complete pollination and fertilization, and the GFP gene was expressed in embryos. Furthermore, apple genes transformed into pollen can be expressed in the pollen tube, allowing verification of gene function. Transformed genes can also be expressed in seeds and seedlings. The most significant advantage of this method is that it does not require fresh pollen. This technique is the simplest and fastest reported transgenic method for transforming genes into pollen.