Expression patterns of Arabidopsis ERF VIII-b subgroup genes during in vitro shoot regeneration and effects of their overexpression on shoot regeneration efficiency

Abstract

The Arabidopsis ESR1, which encodes a member of the ERF family, is thought to be a key gene for commitment to shoot differentiation in tissue culture. The Arabidopsis genome has more than a hundred genes encoding the ERF family and ESR1 belongs to the ERF VIII-b subgroup. We examined ESR1 and 5 genes structurally similar to ESR1 (ESR2, ESL1, ESL2, ESL3 and LEP) on their expression patterns during in vitro shoot regeneration. All these genes' transcript levels increased 1–2 days after shoot induction by incubation on shoot-inducing medium and then decayed by day 7. These genes' overexpression demonstrated that ESR1 and ESR2 clearly enhanced shoot regeneration when overexpressed, but other genes did not. These results suggest that all 6 examined genes may be involved in early events of shoot regeneration, although only ESR1 and ESR2 enhanced shoot regeneration by their overexpression.