AUTHOR=Bai Shu-Nong , Rao Guang-Yuan , Yang Ji 

TITLE=Origins of the seed: The “golden-trio hypothesis”

JOURNAL=Frontiers in Plant Science

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.965000

DOI=10.3389/fpls.2022.965000

ISSN=1664-462X

ABSTRACT=<p>The seed is an evolutionary innovation in the plant kingdom. While human civilization depends heavily on seed production, how the seed trait emerged remains elusive. In this opinion article, a “golden-trio hypothesis” is proposed based on our investigations of <italic>LEC1</italic> gene functions in <italic>Adiantum capillus-veneris</italic>. This hypothesis posits that a “seed program” arose from spatiotemporal integration of three key components: assimilate flow, ABA-mediated stress responses, and stress-induced <italic>LEC1</italic> expression. Thus, the evolutionary innovation of seeds should be considered not a simple event resulting from new genes; rather, it represents the outcome of a series of physiological and morphological innovations that emerged prior to and regardless of the origin of the seed program. This new perspective could help us tackle some long-standing questions around the puzzling origin of seeds.</p>