The tapetal AHL family protein TEK determines nexine formation in the pollen wall

Nat Commun. 2014 May 8;5:3855. doi: 10.1038/ncomms4855.

Abstract

The pollen wall, an essential structure for pollen function, consists of two layers, an inner intine and an outer exine. The latter is further divided into sexine and nexine. Many genes involved in sexine development have been reported, in which the MYB transcription factor Male Sterile 188 (MS188) specifies sexine in Arabidopsis. However, nexine formation remains poorly understood. Here we report the knockout of TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK) leads to nexine absence in Arabidopsis. TEK encodes an AT-hook nuclear localized family protein highly expressed in tapetum during the tetrad stage. Absence of nexine in tek disrupts the deposition of intine without affecting sexine formation. We find that ABORTED MICROSPORES directly regulates the expression of TEK and MS188 in tapetum for the nexine and sexine formation, respectively. Our data show that a transcriptional cascade in the tapetum specifies the development of pollen wall.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism
  • Basic Helix-Loop-Helix Transcription Factors / genetics*
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Cell Wall / physiology
  • Flowers / genetics
  • Gene Expression Regulation, Plant
  • Pollen / genetics*
  • Pollen / metabolism
  • Pollen / physiology

Substances

  • AMS protein, Arabidopsis
  • Arabidopsis Proteins
  • Basic Helix-Loop-Helix Transcription Factors