Mulberry EIL3 confers salt and drought tolerances and modulates ethylene biosynthetic gene expression

Abstract

Ethylene regulates plant abiotic stress responses and tolerances, and ethylene-insensitive3 (EIN3)/EIN3-like (EIL) proteins are the key components of ethylene signal transduction. Although the functions of EIN3/EIL proteins in response to abiotic stresses have been investigated in model plants, little is known in non-model plants, including mulberry (<i>Morus</i> L.), which is an economically important perennial woody plant. We functionally characterized a gene encoding an EIN3-like protein from mulberry, designated as <i>MnEIL3</i>. A quantitative real-time PCR analysis demonstrated that the expression of <i>MnEIL3</i> could be induced in roots and shoot by salt and drought stresses. <i>Arabidopsis</i> overexpressing <i>MnEIL3</i> exhibited an enhanced tolerance to salt and drought stresses. <i>MnEIL3</i> overexpression in <i>Arabidopsis</i> significantly upregulated the transcript abundances of ethylene biosynthetic genes. Furthermore, <i>MnEIL3</i> enhanced the activities of the <i>MnACO1</i> and <i>MnACS1</i> promoters, which respond to salt and drought stresses. Thus, MnEIL3 may play important roles in tolerance to abiotic stresses and the expression of ethylene biosynthetic genes.