An Artificial Conversion of Roots into Organs with Shoot Stem Characteristics by Inducing Two Transcription Factors.

Shigeru Hanano,Shigeyuki Betsuyaku,Tsutomu Hosouchi,Yoshiyuki Ogata,Takahiro Nagase,Eiji Takita,Hiroo Fukuda,Daisuke Shibata,Kunihiro Suda,Hiroshi Masumoto,Hajime Tomatsu,Yuki Kondo,Nozomu Sakurai,Koichi Kobayashi,Keishi Ozawa,Ai Ohnishi,Hideyuki Suzuki

doi:10.1016/j.isci.2020.101332

Abstract

SummarySomatic plant cells can regenerate shoots and/or roots or adventitious embryonic calluses, which may induce organ formation under certain conditions. Such regenerations occur via dedifferentiation of somatic cells, induction of organs, and their subsequent outgrowth. Despite recent advances in understanding of plant regeneration, many details of shoot induction remain unclear. Here, we artificially induced shoot stem-like green organs (SSOs) in Arabidopsis thaliana roots via simultaneous induction of two transcription factors (TFs), ARABIDOPSIS THALIANA HOMEOBOX PROTEIN 25 (ATHB25, At5g65410) and the B3 family transcription factor REPRODUCTIVE MERISTEM 7 (REM7, At3g18960). The SSOs exhibited negative gravitropism and differentiated vascular bundle phenotypes. The ATHB25/REM7 induced the expression of genes controlling shoot stem characteristics by ectopic expression in roots. Intriguingly, the restoration of root growth was seen in the consecutive and adjacent parts of the SSOs under gene induction conditions. Our findings thus provide insights into the development and regeneration of plant shoot stems.

Highlights

De novo organogenesis, so-called regeneration, is widely conserved in both animals and plants and functions to restore structures or organs damaged or lost by various physical assaults, such as injury, diseases, or attack by predators (Ikeuchi et al, 2016; Pulianmackal et al, 2014)
The ATHB25/REM7 induced the expression of genes controlling shoot stem characteristics by ectopic expression in roots
The gene construct was introduced into Arabidopsis plants, and expression of the genes was simultaneously induced in the roots of young seedlings using a ß-estradiol-mediated induction system (Zuo et al, 2000)

Summary

Introduction

-called regeneration, is widely conserved in both animals and plants and functions to restore structures or organs damaged or lost by various physical assaults, such as injury, diseases, or attack by predators (Ikeuchi et al, 2016; Pulianmackal et al, 2014). In the initial process of regeneration, a pluripotent cell mass, termed a callus, is dedifferentiated from somatic cells, and the callus induces formation of shoots and other organs upon treatment with certain phytohormones (Pulianmackal et al, 2014; Skoog and Miller, 1957). Recent studies have reported that callus formation resembles lateral root development processes, suggesting that root stem cell regulators induce callus regenerative to shoot initials (Ikeuchi et al, 2016; Sugimoto et al, 2010). We report the shoot stem induction activated by two transcription factors (TFs) expressed around the shoot apical meristems (SAMs) under normal growth conditions and subsequent restoration of root growth in the consecutive and adjacent parts of the shoot stem-like organs (SSOs) even under the conditions of the gene activation

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Conclusion