Characterization and Functional Analysis of Transcription Factor LoMYB80 Related to Anther Development in Lily (Lilium Oriental Hybrids)

Abstract

Anther development is very precise and complicated procedure. In this study, the gene LoMYB80 was isolated from lily (Lilium Oriental Hybrids cv. cultivar ‘Siberia’) anther. Multiple alignment and phylogenetic tree analysis showed that LoMYB80 belongs to the R2R3 MYB family. Furthermore, the protein of LoMYB80 shares a 44 amino acid sequence immediately adjacent to the R3 domain with other MYB80s. Subcellular localization showed that LoMYB80 was predominantly localized in the nucleus. The transcriptional activation experiment revealed that LoMYB80 belongs to the transcription activation factors and its transactivation activity depends on the last 70 amino acids located at the end of the C-terminal region. Real-time quantitative PCR analysis showed that LoMYB80 gene expression was significantly higher in anther than in other organs; the highest level was in anthers of 10-cm flower buds and then was in anthers of 4-cm buds. The relative expression in microspores/pollen of 10-cm buds was much higher than the whole anther in the same stage and also much higher than the microspore/pollen of 8- and 9-cm buds. The gene was mainly expressed in young anthers at the development stages from 6 to 10 by analyzing transgenic Arabidopsis lines which were transformed with LoMYB80 promoter::GUS reporter gene constructs. Complementation experiments revealed that transgenic ms188 mutant lines could produce normal pollen grains and display partial fertility. These results indicated that LoMYB80 was a regulator of lily anther development and pollen formation.