TsCYP94B1 regulates male fertility in androdioecious Tapiscia sinensis via jasmonic acid metabolism.

Tapiscia sinensis Oliv. (Tapisciaceae), a functionally androdioecious species, displays male individuals with higher pollen viability compared to hermaphrodites. This study elucidates the molecular basis underlying reduced pollen viability and abnormal tapetum development in hermaphroditic flowers. Integrated transcriptomic and functional analyses identified TsCYP94B1, a jasmonate-responsive gene overexpressed in hermaphroditic flowers, as the homolog of AtCYP94B1 from Arabidopsis thaliana that catabolizes bioactive JA-Ile into 12-OH-JA-Ile and 12-COOH-JA-Ile. Elevated TsCYP94B1 expression in hermaphrodites correlates with reduced JA-Ile levels, destabilizing JA signaling essential for male fertility. Heterologous overexpression of TsCYP94B1 in Arabidopsis mimicked JA-Ile deficiency phenotypes: delayed tapetum degradation, impaired pollen viability, and filament elongation defects. High-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) confirmed JA-Ile depletion in hermaphroditic flowers versus males. Crucially, exogenous methyl jasmonate (MeJA) partially restored stamen development and pollen viability, directly linking JA-Ile scarcity to reproductive impairments. We propose that TsCYP94B1 disrupts JA-Ile homeostasis through catalytic conversion, mediating incomplete tapetum degeneration and compromised pollen maturation in hermaphrodites. This mechanism highlights how spatiotemporal JA-Ile regulation via TsCYP94B1 underpins male fertility variation, offering key insights into the maintenance of androdioecy in T. sinensis.