Global Expression Profiling Applied to the Analysis of Arabidopsis Stamen Development

Abstract

To obtain detailed information about gene expression during stamen development in Arabidopsis (Arabidopsis thaliana), we compared, by microarray analysis, the gene expression profile of wild-type inflorescences to those of the floral mutants apetala3, sporocyteless/nozzle, and male sterile1 (ms1), in which different aspects of stamen formation are disrupted. These experiments led to the identification of groups of genes with predicted expression at early, intermediate, and late stages of stamen development. Validation experiments using in situ hybridization confirmed the predicted expression patterns. Additional experiments aimed at characterizing gene expression specifically during microspore formation. To this end, we compared the gene expression profiles of wild-type flowers of distinct developmental stages to those of the ms1 mutant. Computational analysis of the datasets derived from this experiment led to the identification of genes that are likely involved in the control of key developmental processes during microsporogenesis. We also identified a large number of genes whose expression is prolonged in ms1 mutant flowers compared to the wild type. This result suggests that MS1, which encodes a putative transcriptional regulator, is involved in the stage-specific repression of these genes. Lastly, we applied reverse genetics to characterize several of the genes identified in the microarray experiments and uncovered novel regulators of microsporogenesis, including the transcription factor MYB99 and a putative phosphatidylinositol 4-kinase.

Arabidopsis SET DOMAIN GROUP2Is Required for H3K4 Trimethylation and Is Crucial for Both Sporophyte and Gametophyte Development

“…Among them, the MADS-like transcription factor gene SPL/NZZ is of particular interest. It acts upstream of many stamen-and ovule-expressed genes and is required for initiation of both microsporogenesis and megasporogenesis (Schiefthaler et al, 1999;Yang et al, 1999;Yu et al, 2005;Zhang et al, 2006;Alves-Ferreira et al, 2007;Wijeratne et al, 2007). Although knowledge is currently scarce about how SPL/NZZ regulates downstream processes, a gainof-function study suggested that SPL/NZZ might be involved in auxin homeostasis by repression of YUCCA genes in lateral organ development (Li et al, 2008).…”

The ABORTED MICROSPORES Regulatory Network Is Required for Postmeiotic Male Reproductive Development in Arabidopsis thaliana

“…MS1 encodes a plant homeodomain transcription factor that is briefly expressed from the late tetraspore to free microspore stage (Yang et al, 2007). Numerous expression changes have been detected in the ms1 mutant, particularly in genes associated with the deposition of pollen wall materials (Alves-Ferreira et al, 2007;Ito et al, 2007;Yang et al, 2007). Tapetal development was also shown to be altered in this mutant, with a lack of normal PCD and change to autophagic tapetal degeneration occurring (Vizcay-Barrena and Wilson, 2006).…”

“…Microarray comparisons were also made between genes previously shown to have altered expression in the ms1 mutant (Alves-Ferreira et al, 2007;Yang et al, 2007) and those with altered expression in ams. We observed that 152 of 361 genes downregulated in the ams mutant were also downregulated in the ms1 mutant (see Supplemental Data Set 4, Supplemental Figure 8, and Supplemental Table 4 online).…”

Analysis of TETRAKETIDE α-PYRONE REDUCTASE Function in Arabidopsis thaliana Reveals a Previously Unknown, but Conserved, Biochemical Pathway in Sporopollenin Monomer Biosynthesis

“…Pollen wall formation requires exquisite and coordinated spatiotemporal regulation of numerous biosynthetic genes by specific transcriptional regulators (Alves-Ferreira et al, 2007;Ito et al, 2007;Yang et al, 2007). In particular, many genes involved in exine biosynthesis in Arabidopsis have been shown to be repressed by the MS1 transcription factor in wild-type plants and to be overexpressed in the ms1 mutant (Ito et al, 2007;Yang et al, 2007).…”