Apomixis Overview

EASE-Image-2

An ovule showing EGFP expression in the Egg Apparatus, Photo by Dr. Wei Yang, CAMBIA

EASE stands for Egg Apparatus-Specific Enhancer and is a DNA sequence that can direct gene expression in the egg apparatus in Arabidopsis. The relevant research was published in the journal Plant Physiology in November 2005.

Despite a central role in plant reproduction, few gametophyte-specific genes and promoters have been isolated, particularly for the inaccessible female gametophyte (embryo sac). Using the Ds-based enhancer detector line ET253, we have cloned an egg apparatus-specific enhancer (EASE) from Arabidopsis thaliana.

The genomic region flanking the Ds insertion site was further analyzed by examining its capability to control gusA and GFP reporter gene expression in the embryo sac in a transgenic context. Through analysis of a 5′ and 3′ deletion series in transgenic Arabidopsis, the sequence responsible for egg apparatus-specific expression was delineated to 77 bp.

Our data showed that this enhancer is unique in the Arabidopsis genome, is conserved among different accessions, and shows an unusual pattern of sequence variation. This egg apparatus-specific enhancer works independently of position and orientation in Arabidopsis but is probably not associated with any nearby gene, suggesting either that it acts over a large distance or that a cryptic element was detected. Embryo-specific ablation in Arabidopsis was achieved by transactivation of a diphtheria toxin gene under the control of the EASE.

The nucleotide region that confers specificity of expression is described in WO 01/21785. This region, an enhancer, may be used to control expression of a toxin gene to generate female-sterile transgenic plants, or to promote expression of an embryogenesis gene to allow apomixis.

An open silique with EGFP expressing ovules, Photo by Dr. Wei Yang, CAMBIA

What is available in this project?

  • The EASE vector available is pWY-063.1
  • Read the November 2005 Plant Physiology publication: Yang W, Jefferson R A, Huttner E, Moore J M, Gagliano W B, Grossniklaus U (2005) An Egg Apparatus-Specific Enhancer of Arabidopsis, Identified by Enhancer Detection, Plant Physiology 139:1421-1432. Download this paper
  • Read what others have to say about this project, in the Public Discussion Forum

How do I access/use/obtain this technology?

  • Academic or non-profit research organisations can use the EASE sequence as part of an integrated toolkit to develop apomixis in a protected technology commons. The EASE element and other components of this technology will be accessible under terms aligned with the BiOS (Biological Open Source) License, with no restrictions other than covenants for sharing of improvements, relevant safety information and regulatory data and for preserving the opportunity for others to freely improve and use the technology.
    Please e-mail us for information.View the ‘shrink wrap’ Bios License agreement for EASE vector pWY-O63.1If you have further questions about this project, post your questions, ideas and suggestions on the Public Discussion Forum.