AMS-dependent and independent regulation of anther transcriptome and comparison with those affected by other Arabidopsis anther genes

Xuan Ma,Baomin Feng,Hong Ma

doi:10.1186/1471-2229-12-23

Abstract

BackgroundIn flowering plants, the development of male reproductive organs is controlled precisely to achieve successful fertilization and reproduction. Despite the increasing knowledge of genes that contribute to anther development, the regulatory mechanisms controlling this process are still unclear.ResultsIn this study, we analyzed the transcriptome profiles of early anthers of sterile mutants aborted microspores (ams) and found that 1,368 genes were differentially expressed in ams compared to wild type anthers, affecting metabolism, transportation, ubiquitination and stress response. Moreover, the lack of significant enrichment of potential AMS binding sites (E-box) in the promoters of differentially expressed genes suggests both direct and indirect regulation for AMS-dependent regulation of anther transcriptome involving other transcription factors. Combining ams transcriptome profiles with those of two other sterile mutants, spl/nzz and ems1/exs, expression of 3,058 genes were altered in at least one mutant. Our investigation of expression patterns of major transcription factor families, such as bHLH, MYB and MADS, suggested that some closely related homologs of known anther developmental genes might also have similar functions. Additionally, comparison of expression levels of genes in different organs suggested that anther-preferential genes could play important roles in anther development.ConclusionAnalysis of ams anther transcriptome and its comparison with those of spl/nzz and ems1/exs anthers uncovered overlapping and distinct sets of regulated genes, including those encoding transcription factors and other proteins. These results support an expanded regulatory network for early anther development, providing a series of hypotheses for future experimentation.

Highlights

In flowering plants, the development of male reproductive organs is controlled precisely to achieve successful fertilization and reproduction
We found that many transcription factor genes were preferentially expressed during early anther development, such as Basic helixloop-helix (bHLH), Myeloblastosis-like gene (MYB), and MADS
Identification of genes regulated by Aborted microspores (AMS) To characterize genes involved in tapetum development and function near the time of meiosis, we isolated total RNA of stage 4-7 anthers from wild-type and the ams mutant plants for Affymatrix ATH1 microarray analysis

Summary

Introduction

The development of male reproductive organs is controlled precisely to achieve successful fertilization and reproduction. Male reproductive organs are called stamens, each of which consists of a filament and an anther [1]. Anther development is critical to achieve pollen formation and subsequent success of fertilization [3,4,5,6]. The SPOROCYTELESS (SPL)/ NOZZLE (NZZ) gene is one of the earliest genes that regulate anther cell fate determination [10,11]. SPL/NZZ is expressed as early as anther stage 2-5 and a mutation in SPL/NZZ leads to the failure of differentiation of parietal and sporogenous cells, and consequentially blocks the formation of anther wall and microsporocytes [15,16]

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Results

Conclusion