, Volume 233, Issue 2, pp 423–431

Effect of sporophytic PIRL9 genotype on post-meiotic expression of the Arabidopsis pirl1;pirl9 mutant pollen phenotype

Rapid Communication

DOI: 10.1007/s00425-010-1324-5

Cite this article as:
Forsthoefel, N.R. & Vernon, D.M. Planta (2011) 233: 423. doi:10.1007/s00425-010-1324-5


Plant intracellular ras-group-related leucine-rich repeat proteins (PIRLs) are a novel class of plant leucine-rich repeat (LRR) proteins structurally related to animal ras-group LRRs involved in cell signaling and gene regulation. Gene knockout analysis has shown that two members of the Arabidopsis thalianaPIRL gene family, PIRL1 and PIRL9, are redundant and essential for pollen development and viability: pirl1;pirl9 microspores produced by pirl1/PIRL1;pirl9 plants consistently abort just before pollen mitosis I. qrt1 tetrad analysis demonstrated that the genes become essential after meiosis, during anther stage 10. In this study, we characterized the phenotype of pirl1;pirl9 pollen produced by plants heterozygous for pirl9 (pirl1;pirl9/PIRL9). Alexander’s staining, scanning electron microscopy, and fluorescence microscopy indicated that pirl1;pirl9 double mutants produced by pirl9 heterozygotes have a less severe phenotype and more variable morphology than pirl1;pirl9 pollen from pirl1/PIRL1;pirl9 plants. Mutant pollen underwent developmental arrest with variable timing, often progressing beyond pollen mitosis I and arresting at the binucleate stage. Thus, although the pirl1 and pirl9 mutations act post-meiosis, the timing and expressivity of the pirl1;pirl9 pollen phenotype depends on the pirl9 genotype of the parent plant. These results suggest a continued requirement for PIRL1 and PIRL9 beyond the initiation of pollen mitosis. Furthermore, they reveal a modest but novel sporophytic effect in which parent plant genotype influences a mutant phenotype expressed in the haploid generation.


Arabidopsis thaliana Gametophyte Gene knockout Genetic redundancy Paternal effect Pollen development 





Leucine-rich repeat


Plant intracellular ras-group-related LRR protein


Scanning electron microscopy

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  1. 1.Department of BiologyWhitman CollegeWalla WallaUSA
  2. 2.Program in Biochemistry, Biophysics and Molecular BiologyWhitman CollegeWalla WallaUSA

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