Molecular analysis of NOZZLE , a gene involved in pattern formation and early sporogenesis during sex organ development in Arabidopsis thaliana

Abstract

Sexual reproduction is a salient aspect of plants, and elaborate structures, such as the f lowers of angiosperms, have evolved that aid in this process. Within the f lower the corresponding sex organs, the anther and the ovule, form the male and female sporangia, the pollen sac and the nucellus, respectively. However, despite their central role for sexual reproduction little is known about the mechanisms that control the establishment of these important structures. Here we present the identification and molecular characterization of the NOZZLE (NZZ) gene in the f lowering plant Arabidopsis thaliana. In several nzz mutants the nucellus and the pollen sac fail to form. It indicates that NZZ plays an early and central role in the development of both types of sporangia and that the mechanisms controlling these processes share a crucial factor. In addition, NZZ may have an early function during male and female sporogenesis as well. The evolutionary aspects of these findings are discussed. NZZ encodes a putative protein of unknown function. However, based on sequence analysis we speculate that NZZ is a nuclear protein and possibly a transcription factor.

Global Expression Profiling Applied to the Analysis of Arabidopsis Stamen Development

“…Strains, Plant Growth, and Genotyping ap3-3 (Jack et al, 1992), nzz-1 (Schiefthaler et al, 1999), and ms1-1 (van der Veen and Wirtz, 1968) mutants, as well as wild-type plants of accession Landsberg erecta, were grown on a soil:vermiculite:perlite mixture under constant illumination at 20°C. T-DNA insertion lines (Supplemental Table S5; Alonso et al, 2003) for selected genes identified in this study were obtained from the Arabidopsis Biological Resource Center (Ohio State University).…”

“…In spl/nzz mutants, the nucellus and the pollen sac fail to form, indicating that SPL/NZZ, which encodes a putative transcription factor, plays a key role in the development of both male and female sporangia (Schiefthaler et al, 1999;Yang et al, 1999). ms1 mutants do not produce viable pollen but are otherwise phenotypically normal (Wilson et al, 2001;Ito and Shinozaki, 2002).…”

“…Genetic analyses have led to the isolation of several mutants with distinct defects in stamen development (Dawson et al, 1993;Sanders et al, 1999;Schiefthaler et al, 1999;Yang et al, 1999;Canales et al, 2002;Zhao et al, 2002;Reddy et al, 2003;Sorensen et al, 2003;Steiner-Lange et al, 2003;Albrecht et al, 2005). Cloning of the genes affected in these mutants resulted in the identification of key regulators of stamen formation.…”

The Arabidopsis CALLOSE DEFECTIVE MICROSPORE1 Gene Is Required for Male Fertility through Regulating Callose Metabolism during Microsporogenesis

“…In Arabidopsis, SPOROCYTELESS (SPL) and EXCESS MICROSPOROCYTE1 (EMS1) are two important genes regulating microsporogenesis (Schiefthaler et al, 1999;Yang et al, 1999;Zhao et al, 2002). In an effort to identify new genes for anther and pollen development, we compared gene expression profiles between wildtype and spl and ems1 mutant anthers (Wijeratne et al, 2007).…”

Spore formation in plants: SPOROCYTELESS and more

“…The specification of the sporocytes represents a critical step in the process of sporogenesis. The SPOROCYTE-LESS/NOZZLE (SPL/NZZ) gene which encodes a nuclear protein was identified as a key regulator of this stage of sporogenesis in Arabdiopsis [1,2]. In spl/nzz mutants, development of both male and female reproductive organs proceeds normally until the ACs are formed, but the ACs fail to differentiate into sporocytes.…”