Journal Article

Biphasic regulation of the transcription factor ABORTED MICROSPORES (AMS) is essential for tapetum and pollen development in Arabidopsis

Ivana Ferjentsikova, Dabing Zhang, Simon Pearce, John King, Caiyun Yang, Zoe A. Wilson, Leah R. Band, Alison C. Ferguson, Zheng Yuan

2017

Overview

Viable pollen is essential for plant reproduction and crop yield. Its production requires coordinated expression at specific stages during anther development, involving early meiosis-associated events and late pollen wall formation. The ABORTED MICROSPORES (AMS) transcription factor is a master regulator of sporopollenin biosynthesis, secretion and pollen wall formation in Arabidopsis. Here we show that it has complex regulation and additional essential roles earlier in pollen formation. An inducible-AMS reporter was created for functional rescue, protein expression pattern analysis, and to distinguish between direct and indirect targets. Mathematical modelling was used to create regulatory networks based on wild-type RNA and protein expression. Dual activity of AMS was defined by biphasic protein expression in anther tapetal cells, with an initial peak around pollen meiosis and then later during pollen wall development. Direct AMS-regulated targets exhibit temporal regulation, indicating that additional factors are associated with their regulation. We demonstrate that AMS biphasic expression is essential for pollen development, and defines distinct functional activities during early and late pollen development. Mathematical modelling suggests that AMS may competitively form a protein complex with other tapetumexpressed transcription factors, and that biphasic regulation is due to repression of upstream regulators and promotion of AMS protein degradation.

• Publisher: New Phytologist Trust,Wiley Subscription Services, Inc,John Wiley and Sons Inc
• Subject: aborted microspores (AMS) / anther development / Arabidopsis / Arabidopsis - drug effects / Arabidopsis - genetics / Arabidopsis - growth & development / Arabidopsis - metabolism / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Basic Helix-Loop-Helix Transcription Factors - metabolism / Biodegradation / Biosynthesis / Crop production / Crop yield / Dexamethasone - pharmacology / Fertility - drug effects / Gene expression / Gene Expression Regulation, Plant - drug effects / Gene regulation / Mathematical analysis / Mathematical models / Meiosis / Microspores / Model testing / Modelling / Models, Biological / Mutation - genetics / Pattern analysis / Plant reproduction / Pollen / Pollen - drug effects / Pollen - genetics / Pollen - growth & development / Pollen - metabolism / pollen development / Protein Binding - drug effects / protein degradation / Protein expression / protein synthesis / Proteins / Proteolysis - drug effects / Recombinant Fusion Proteins - metabolism / regulatory network modelling / RNA / Secretion / sporopollenin / tapetum / Transcription / transcription (genetics) / Transcription factors