NcFER1 and NcRbohC1 Regulate Pollen Germination on Waterlily Stigma After Pollination

The hybridization between hardy and tropical waterlilies is the main way to breed new varieties of waterlilies with strong cold resistance and rich flower colors. However, there is a hybridization barrier between hardy and tropical waterlilies, which seriously affects the breeding process of waterlilies. Therefore, it is necessary to study the mechanism of hybridization barriers in waterlilies. The results showed that the pollen of tropical waterlily could not germinate on the stigma of hardy waterlily. ROS (reactive oxygen species) play an important role in the recognition of pollen and stigma of waterlily during pollination and are involved in the regulation of pollen germination on the stigma of waterlily. Rbohs (respiratory burst oxidase homolog protein) is the main source of ROS, and NcFER1 (FERONIA) and NcRbohC1 are the main regulatory factors of ROS in waterlily's stigma. These results suggest that pre-fertilization barrier is the main cause of hybridization barrier between hardy and tropical waterlilies. NcRbohC1 may be the downstream element of NcFER1, and NcFER1 may regulate the metabolism of ROS in waterlily's stigma through the signaling pathway of FER-Rac/Rops-Rbohs, but its specific mechanism remains unclear.