Institute of Fruit Tree Research, Guangdong Academy of Agricultural Sciences, Guangzhou, China.
Key Laboratory of South Subtropical Fruit Biology and Genetic Resource Utilization, Ministry of Agriculture, Guangzhou, China.
BMC Plant Biol. 2020 Aug 31;20(1):402. doi: 10.1186/s12870-020-02623-w.
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.
花粉的形成和发育对于作物的育性至关重要，是杂种发育的关键因素。先前的研究表明，拟南芥 TAPETUM DETERMINANT1（AtTPD1）及其水稻同源物 OsTPD1-like（OsTDL1A）对于细胞特化非常重要，并极大地影响花粉的形成和发育。然而，关于 TPD1 同源物在香蕉花粉发育中的作用知之甚少。
本研究鉴定并描述了二倍体香蕉（Musa itinerans）中 TPD1 同源物，并通过过表达最接近的同源物 MaTPD1A 来研究其在花粉发育中的作用。MaTPD1A 在雄蕊中高表达，并定位于质膜上。与野生型植物相比，MaTPD1A 过表达植株产生的花粉粒较少，果实更小且无种子。转录组分析表明，在植物激素、淀粉和蔗糖代谢以及亚麻酸代谢相关途径中，过表达 MaTPD1A 会受到影响，并且一些关键调控因子（如已知影响花药发育的 PTC1 和 MYB80）的表达在 MaTPD1A 过表达系中受到影响。
本研究结果表明，MaTPD1A 在二倍体香蕉花粉形成和果实发育中起重要作用，可能通过影响花粉发育的一些关键调控因子的表达来实现。
