Transcriptomic analysis of Medicago truncatula calli with MtWOX9-1 overexpression

V E Tvorogova,K A Kuznetsova,Y A Fedorova,E Y Krasnoperova,L A Lutova,A A Kudriashov,E A Potsenkovskaya

doi:10.18699/vj19.542

V E Tvorogova, K A Kuznetsova + Show 5 more

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https://doi.org/10.18699/vj19.542

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Abstract

Somatic embryogenesis (SE) is the development of embryo-like structures from somatic plant tissues. This process rarely can be observed in nature, but for many plant species, in vitro protocols are developed, which allow to obtain somatic embryos formation directly from tissues of plant explant or from the embryogenic callus. SE is widely used for plant propagation and transformation; therefore, the search for SE stimulators and revealing of the mechanisms of their functioning are very important for biotechnology. Among the SE regulators, proteins of the WOX family play significant roles. WOX (WUSCHEL-RELATED HOMEOBOX) is a homeodomain-containing transcription factor family. Different WOX genes function in different plant organs and tissues, maintaining meristem activity and regulating cell proliferation and differentiation. Recently, we have shown that transcription factor MtWOX9-1, belonging to the WOX family, can stimulate SE in the Medicago truncatula callus culture. In this research, transcriptomic analysis of highly embryogenic calli with MtWOX9-1 overexpression was performed in comparison to wildtype calli. It was shown that MtWOX9-1 overexpression led to the activation of several groups of genes, including genes related to cell division, tissue differentiation, and seed development. Enriched GO pathways included several groups related to histone methyltransferase activity as well as DNA methylation and chromatin binding, suggesting major epigenetic changes that occur in call overexpressing MtWOX9-1. Using Medicago Truncatula Gene Expression Atlas, we also identified a group of genes coding for transcription factors that were both coexpressed with MtWOX9-1 in different plant organs and differentially expressed in our samples. These genes are putative targets of MtWOX9-1, and they may act in the same pathway with this regulator during SE.

Highlights

Somatic embryogenesis (SE) is a process of regeneration by which plants use somatic cells to grow embryo-like structures, which eventually can give rise to the new plant
In this study, we analyzed transcriptome of embryogenic calli, affected by overexpression of SE stimulator MtWOX9-1
It is important to note that in this study we used a single line with MtWOX9-1 overexpression, one cannot exclude the possibility that observed effects are related with specific location of transgenic insert in this line

Summary

Introduction

Somatic embryogenesis (SE) is a process of regeneration by which plants use somatic cells to grow embryo-like structures, which eventually can give rise to the new plant. This process isn’t observed often in nature, but when plant explants are cultivated in vitro, several factors can induce direct SE or SE from callus tissue. The most well-studied family members are WUS and WOX5 genes, which are expressed in the organizing and quiescent center cells of the shoot and root apical meristem (SAM and RAM), respectively, and regulate their development (Laux et al, 1996; Sarkar et al, 2007). We concentrated on studying the functions of the MtWOX9-1 gene, analyzing how its overexpression affects the expression profile of embryogenic callus

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