ORIGINAL PAPER Distribution of cellulosic wall in the anthers of Arabidopsis during microsporogenesis Yuichi Matsuo • Shin-ichi Arimura • Nobuhiro Tsutsumi Received: 7 May 2013 / Accepted: 17 July 2013 Ó Springer-Verlag Berlin Heidelberg 2013 Abstract Key message Cellulose-specific staining revealed that tapetal cells and microsporocytes lose cellulosic walls before the onset of meiosis. Cellulosic wall degradation in microsporocytes might be independent of tapetal cells (or TPD1). Abstract Some cell types in a variety of angiosperms have been reported to lack cell walls. Here, we report that the tapetal cells of the anther of Arabidopsis thaliana did not appear to have a cellulosic wall based on staining with Calcofluor and Renaissance 2200. During sporogenous cell formation, cellulosic wall was present in all anther tissues. However, before meiosis it was almost absent on the tap- etal cells and on the microsporocytes. In a sporocyteless/ nozzle (spl/nzz) mutant, which lacks several components (microsporocytes, tapetum, middle layer and endothe- cium), cellulosic wall was detected in all anther cells. In another mutant, tapetum determinant1 (tpd1), which lacks tapetum and has more microsporocytes, cellulosic wall was almost absent on the microsporocytes before meiosis, similar to the wild type. These results suggest that the tapetum cells and microsporocytes lose cellulosic walls during microsporocyte formation, and that cell wall deg- radation occurs downstream of SPL/NZZ and is indepen- dent of TPD1. Keywords Arabidopsis Á Cell wall Á Sterility Á Microsporogenesis Á Tapetum Á Cellulose Abbreviations SPL/NZZ SPOROCYTELESS/NOZZLE TPD1 TAPETUM DETERMINANT1 Introduction In spite of its agricultural importance, the mechanism of anther development is not well understood. Anther devel- opment of Arabidopsis thaliana is divided into 14 stages (Sanders et al. 1999). All anther cell types (central microspore mother cells, inner tapetum, middle layer and outer endothecium) are present at stage 5. After meiosis of microspore mother cells, at stage 7, the tapetum secretes enzymes to hydrolyze the tetrad wall (Hird et al. 1993). The fact that male sterility is often accompanied by abnormal tapetal function shows that the tapetum has an important role in anther development. However, the mechanism of tapetal development and function during early anther development is largely unknown. The majority of cell types in plants have cell walls, some of the exceptions being tapetal cells, egg cells and sperm cells (Albersheim et al. 2010). In Helleborus, electron microscopy revealed that tapetal cell walls were thin when they are differentiated, that they become thick during microsporocyte formation and that they appear to be degraded during tetrad formation (Echlin and Godwin 1968). The increase in tapetal cell wall thickness was also visible before meiosis by electron microscopy in Avena, although fluorescent staining revealed that the cell wall had already lost their cellulose (Steer 1977). The difference between the result of electron microscopy and that of fluorescent staining is caused by the specificity of fluo- rescent staining for cellulose. So, fluorescent staining is Communicated by A.-C. Schmit. Y. Matsuo Á S. Arimura Á N. Tsutsumi (&) Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan e-mail: atsutsu@mail.ecc.u-tokyo.ac.jp 123 Plant Cell Rep DOI 10.1007/s00299-013-1487-1