Reproductive Strategies of the Female Gametophyte

Abstract

Reproduction refers to the biological process of producing offspring. Sexual reproduction in angiosperms is a complex and precise process of regulation, which requires the mutual recognition of male and female gametes. The pollen tube, as a medium for transmission of male gametes, is attracted by chemoattractant derived from synergid cells in a target ovule. We first identified that MYB98 plays an important role in pollen tube guidance by regulating the downstream LURE peptides. Moreover, we discovered that if the first pollen tube penetrates the ovule but fertilization fails, the second pollen tube is attracted by another synergid cell to increase the chances of fertilization as a “wise” back-up system (Fertilization Recovery System). Similar feedback mechanisms also occur to seed development after the pollen tube guidance. We further identified a phenomenon, the pollen tube-dependent ovule enlargement morphology (POEM), that the pollen tube contents (PTCs) enlarge ovules and initiate seed coat formation without fertilization. Furthermore, we identified the POEM in rice by knocked-out GCS1 genes in rice genome, which led to fertilization failure and to produce enlarged sugar grain. In this chapter, we discuss from the reproductive strategies of the plants to the agricultural application based on our previous discoveries.