Overexpression of MaTPD1A impairs fruit and pollen development by modulating some regulators in Musa itinerans

Pollen formation and development is important for crop fertility and is a key factor for hybrid development. Previous reports have indicated that Arabidopsis thaliana TAPETUM DETERMINANT1 (AtTPD1) and its rice (Oryza sativa) homolog, OsTPD1-like (OsTDL1A), are required for cell specialization and greatly affect pollen formation and development. Little is known about the role of the TPD1 homolog in banana pollen development.

Here, we report the identification and characterization of TPD1 homologs in diploid banana (Musa itinerans) and examine their role in pollen development by overexpressing the closest homolog, MaTPD1A. MaTPD1A exhibits high expression in stamen and localizes in the plasma membrane. MaTPD1A-overexpressing plants produce no pollen grains and smaller and seedless fruit compared to wild-type plants. Transcriptome analysis showed that in plant hormone, starch and sucrose metabolism, and linolenic acid metabolism-related pathways were affected by overexpression of MaTPD1A, and the expression of several key regulators, such as PTC1 and MYB80, which are known to affect anther development, is affected in MaTPD1A-overexpressing lines.

Our results indicate that MaTPD1A plays an important role in pollen formation and fruit development in diploid banana, possibly by affecting the expression of some key regulators of pollen development.