Overexpression of the ethylene response factor SIERF1 gene enhances resistance of tomato fruit to Rhizopus nigricans

The tomato SIERF1 gene belongs to a distinct subfamily of the large ERF gene family. It is a downstream component in the ethylene signaling pathway in tomato, and is involved in plant defense and stress responses. Overexpression of the SIERF1 gene (SIERF1-OEs) in tomato dramatically enhanced the resistance of fruit to Rhizopus nigricans. In attempt to elucidate the mechanism basis of this observation, our study revealed a dual modulation. Firstly. SIERF1-OEs fruit showed a remarkable transcript accumulation of PR5 and PAL genes before infection with R. nigricans, which was not observed in wild-type (WT) fruit. Secondly. SIERF1-OEs fruit had higher activitiers of phenylalanine ammonia Iyase (PAL) and chitinase (CHI) in response to the fungal stress. These results show that SIERF1 positively modulated the ethylene-dependent pathogenesis defense pathway in tomato. That may be one of the mechanisms by which ERFs enhance plant tolerance to fungal invasion. (c) 2012 Elsevier B.V. All rights reserved.