During double fertilization, two sperm cells are delivered through the pollen tube to the egg cell and central cell, and fusion of these two pairs of gametes results in formation of the embryo and endosperm (Zhong et al. 2025). In Arabidopsis thaliana, gamete fusion occurs rapidly, completing about seven minutes after pollen tube rupture (Hamamura et al. 2011). Despite their importance in double fertilization, many aspects of sperm cell behavior and the molecular mechanisms involved remain unresolved. To our knowledge, calcium dynamics in sperm cells before or after double fertilization have not been well characterized, partly due to an enigmatic gene silencing phenomenon in sperm cells termed GESENI [gesénài] (GEne Silencing based on ENcoded protein’s Intracellular localization). This term means “incomprehensible” in Japanese (Ohnishi and Kawashima, 2023). Here, we describe a strategy that enables expression of transgenes susceptible to GESENI.