Systems analysis of networks for pollen development

Systems analysis of tapetal regulatory networks required for pollen development

Pollen development is fundamental to plant fertilisation and seed formation, and is thus vital for food production. Controlling pollen fertility is critical in plant breeding and in hybrid production, with hybrid crops frequently out-yielding selfed lines by 20-30%. Developing a greater understanding of pollen development and the means to manipulate this for selective breeding, maximising fertilization and hybrid production are essential for increased productivity and sustainable agriculture. One of the most important anther tissues involved in pollen formation is the tapetum, which is in direct contact with the developing microspores and plays a major role in meiotic progression, microspore maturation and pollen wall formation. A number of transcription factors that are involved in regulating gene expression and function of the tapetum have been identified; one key transcription factor is ABORTED MICROSPORES (AMS). AMS expression is prolonged, from meiosis until tapetal degeneration during Pollen Mitosis II (PMII), implying multiple roles for AMS during anther development. We have identified ams transcriptional changes and confirmed late AMS targets, including an ABC transporter that is critical for pollen wall deposition and viable pollen formation, however AMS is also involved in additional earlier events in pollen development. We will conduct functional analyses of the AMS expression network to gain a greater insight on events occurring throughout tapetal development and aid understanding on the regulation and transfer of factors between the tapetum and developing microspores. Network inference and functional testing, combined with cell-specific mathematical modelling will be used to identify the principal players in the network and explore their regulatory relationships. This will facilitate a greater understanding of the relationship between the tapetum and developing microspores and of pollen formation in dicots and monocots.