PhD defence
The role of AGC kinases and auxin in male fertility
- T. Zhao
- Date
- Wednesday 22 October 2025
- Time
- Address
-
Academy Building
Rapenburg 73
2311 GJ Leiden
Supervisor(s)
- Prof.dr. R. Offringa
- Prof.dr. S. Balazadeh (Göttingen University)
- dr. T. Munnik (UvA)
Summary
The yield of major food crops depends on the success of sexual reproduction, male fertility is crucial for this process. Many factors contribute to male fertility, one of them is the length of flower filaments. Previous study showed PDK1-PAX/D6PK signaling regulates auxin transport, here my study showed that this signaling boosts male fertility by promoting auxin transport-dependent filament elongation.
As the male gametophyte, the development of pollen has been extensively studied in the past decades. Here, my study focuses on pollen germination and pollen tube growth. The correct timing of pollen germination strongly affects the grain yield. I found that the loss of function of two AGC kinases (PDK1/2 or AGC1.5/7) both led to precocious pollen germination on anther. Further study revealed that the AGC kinases-driven signaling cascade (PDK1-AGC1.5/7-ROPGEFs) determines the correct timing of pollen germination. Though the loss of PDK1 and PDK2 function caused an accumulation of auxin in pollen, my research indicated that this accumulation might merely be a side effect of impaired auxin transport, rather than the cause of precocious pollen germination.
Pollen tube growth is a typical polarized cell growth type in plants and this process serves to deliver gametes to the ovule for successful fertilization. Loss of function of PDK1/2 or AGC1.5/7 caused depolarized pollen tube growth. My study showed that AGC1.5/7 is also downstream of PDK1 regulating polarized pollen tube growth.
Together, these insights advance our understanding of plant reproduction and provide a framework for future studies on fertility regulation and crop improvement.
PhD dissertations
Approximately one week after the defence, PhD dissertations by Leiden PhD students are available digitally through the Leiden Repository, that offers free access to these PhD dissertations. Please note that in some cases a dissertation may be under embargo temporarily and access to its full-text version will only be granted later.
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