The 2HA line of Medicago truncatulahas characteristics of an epigenetic mutant that is weakly ethylene insensitive

BMC Plant Biology

Research Article

Ulrike Mathesius¹  Nicolas Goffard²  Bernard J Carroll³  Kim E Nolan⁴  Michael B Sheahan⁴  Ray J Rose⁴  Sergey Kurdyukov⁵ 

[1] Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia;Division of Plant Science, Research School of Biology, Australian National University, Canberra, Australia;Enterome Bioscience, Paris, France;School of Chemistry & Molecular Biosciences, University of Queensland, Brisbane, Australia;School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, Australia;School of Environmental & Life Sciences, University of Newcastle, Callaghan, NSW, Australia;Kolling Institute of Medical Research, Royal North Shore Hospital, St Leonards, NSW, Australia;

关键词: 2HA seed line;    Somatic embryogenesis;    Ethylene insensitivity;    Nodulation;    Root growth;    Medicago truncatula;    Epigenetics;    DNA methylation;    miRNA;   

DOI  :  10.1186/1471-2229-14-174

 received in 2014-02-20, accepted in 2014-06-12,  发布年份 2014

来源: Springer

【 摘 要 】

BackgroundThe Medicago truncatula 2HA seed line is highly embryogenic while the parental line Jemalong rarely produces embryos. The 2HA line was developed from one of the rare Jemalong regenerates and this method for obtaining a highly regenerable genotype in M. truncatula is readily reproducible suggesting an epigenetic mechanism. Microarray transcriptomic analysis showed down regulation of an ETHYLENE INSENSITIVE 3-like gene in 2HA callus which provided an approach to investigating epigenetic regulation of genes related to ethylene signalling and the 2HA phenotype. Ethylene is involved in many developmental processes including somatic embryogenesis (SE) and is associated with stress responses.ResultsMicroarray transcriptomic analysis showed a significant number of up-regulated transcripts in 2HA tissue culture, including nodule and embryo specific genes and transposon-like genes, while only a few genes were down-regulated, including an EIN3-like gene we called MtEIL1. This reduced expression was associated with ethylene insensitivity of 2HA plants that was further investigated. The weak ethylene insensitivity affected root and nodule development. Sequencing of MtEIL1 found no difference between 2HA and wild-type plants. DNA methylation analysis of MtEIL1 revealed significant difference between 2HA and wild-type plants. Tiling arrays demonstrated an elevated level of miRNA in 2HA plants that hybridised to the antisense strand of the MtEIL1 gene. AFLP-like methylation profiling revealed more differences in DNA methylation between 2HA and wild-type. Segregation analysis demonstrated the recessive nature of the eil1 phenotype and the dominant nature of the SE trait.ConclusionsWe have demonstrated that EIL1 of Medicago truncatula (MtEIL1) is epigenetically silenced in the 2HA seed line. The possible cause is an elevated level of miRNA that targets its 3’UTR and is also associated with DNA methylation of MtEIL1. Down regulation of MtEIL1 makes it possible to form nodules in the presence of ethylene and affects root growth under normal conditions. Segregation analysis showed no association between MtEIL1 expression and SE in culture but the role and mechanism of ethylene signalling in the process of plant regeneration through SE requires further investigation. The work also suggests that epigenetic changes to a particular gene induced in culture can be fixed in regenerated plants.

【 授权许可】

Unknown   
© Kurdyukov et al.; licensee BioMed Central Ltd. 2014. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.