Title : Genetic suppression of indeterminate meristem growth reveals hidden plasticity between annual and perennial life histories in arabidopsis thaliana
Abstract:
Plants adopt annual or perennial life history strategies by integrating environmental cues such as photoperiod and temperature into developmental programs that control meristem fate. While woody perennials are thought to have evolved through complex genetic changes, recent evidence suggests that perennial traits can emerge from relatively minor regulatory modifications. In Arabidopsis thaliana, the annual model plant, the soc1 ful double mutant exhibits extreme meristem indeterminacy, floral reversion, and recurrent vegetative growth, resembling perennial-like behavior. To uncover genetic factors that suppress this indeterminate growth, I performed an EMS mutagenesis suppressor screen in the soc1 ful background. From ~500 M2 lines, I identified seven heritable suppressors, including a strong allele designated sig-1 (suppressor of indeterminate growth-1).
The sig-1 mutation markedly restores meristem determinacy and suppresses vegetative reversion, indicating the existence of a previously unrecognized regulatory layer controlling life history traits. Ongoing work focuses on cloning the SIG locus via fine mapping and functional validation, followed by phenotypic and molecular analyses to define its role in meristem identity, flowering time, and longevity. I will further test whether SIG interacts genetically or physically with SOC1 and FUL, and whether it integrates low-temperature and gibberellin signaling pathways known to modulate floral reversion. Together, this study demonstrates that perennial-like traits in an annual plant can be actively suppressed by specific regulatory genes, highlighting unexpected plasticity in plant life history programs and providing a conceptual framework for engineering perennial traits in annual crops.
