Do egg cell‐secreted aspartic proteases promote gamete attachment?

Response to Zhang et al., ‘do egg cell‐secreted aspartic proteases promote gamete attachment?’

“…Nevertheless, in order to consolidate our claim, we conducted new pollination experiments with 50-only pollen grains, in which almost no polytubey induced by fertilization recovery is observed at all (Figure 1A, B). We observed that 8.3% ± 2.8% ovules with one sperm cell and 2.0% ± 1.4% ovules with one sperm cell pair being detained outside the egg cell (Figure 1C, D), consistent with the results reported in Jiang et al (2022), clearly indicating that the persistent sperm cell/the pair of sperm cells in the ovule was not from the fertilization recovery-induced secondary pollen tubes, excluding the possibility raised in Zhang et al (2023a). As for the number of sperm cells in the image, it is, in our case, relatively easy to distinguish whether there is only one sperm cell or two sperm cells sitting beside the egg cell under NIKON A1R microscope with a 40× magnification objective lens (1.15 WI).…”