Expression Profiling and Functional Characterization of LoNCED Gene in Pollen Abortion of Lilium spp.

Lilium spp. are widely cultivated for their ornamental value, but excessive pollen production poses commercial challenges. Male sterility, especially pollen-free cultivars, offers a promising breeding strategy to improve market appeal. ABA, a key hormone in regulating anther development, is influenced by the NCED gene. To investigate its role in male sterility, we isolated the LoNCED gene from both fertile and sterile lily progenies. After cloning and analyzing its tissue-specific expression, we explored its function through homologous transient overexpression and heterologous expression. Results showed that sterile progenies had significantly higher ABA levels, with LoNCED expression elevated in their anthers compared to fertile progenies. The LoNCED gene, with a 1812 bp open reading frame encoding 603 amino acids, encodes a hydrophilic protein (66.69 kDa) localized in chloroplasts and mitochondria. Sequence analysis revealed high similarity to NCED proteins from other species. Overexpression of LoNCED downregulated key anther development genes ( DYT1 , TDF1 , CYP703A2 , CALS5 , DEX1 ) and caused tapetum degradation, abnormal microspore development, and pollen sterility. Transgenic Arabidopsis plants overexpressing LoNCED exhibited incomplete anther development, premature tapetum degradation, and reduced pollen grain production. These findings highlight the critical role of LoNCED in regulating anther sterility in lilies.