Inspiration from apomictic species of Rutaceae: AGL11-FIE module induces autonomous development of maize embryo and endosperm without fertilization

Abstract

Apomixis is a form of asexual reproduction that produces offspring with the same genetic material as the female parent. Introducing apomixis into major food crops would revolutionize agricultural breeding by allowing the self-propagation of superior hybrids. We found that the MADS-box transcription factor D-class member AGAMOUS-like 11 (AGL11) plays a key role in the apomictic species Zanthoxylum bungeanum during somatic embryogenesis. Specific overexpression of the AGL11 gene in the nucellus induces somatic cells (nucellus cells) to differentiate into asexual embryos (adventitious embryos) and appear to be polyembryonic. FERTILIZATION-INDEPENDENT ENDOSPERM (FIE) acts as a switch to repress the development of the endosperm until fertilization, and knockdown of the FIE gene activates early cellularization of the central polar nucleus and produces a diploid endosperm independent of fertilization. AGL11-OE/fie-mutant maize was constructed by overexpressing AGL11 and knocking out the FIE gene in food crop maize, which produces asexual seeds by inducing somatic embryogenesis and autonomous endosperm. The AGL11-FIE module bypasses sexual reproduction and meiosis and induces asexual embryos and endosperm without fertilization, realizing the transformation of sexual reproduction into asexual reproduction. The results provided a reference for the self-production of hybrid seeds represented by maize.