Pathogen-induced ERF68 regulates hypersensitive cell death and defense response in tomato (Solanum lycopersicum L.)
Date Issued
2016
Date
2016
Author(s)
Liu, An-Chi
Abstract
Ethylene response factors (ERFs) are a large plant-specific transcription factor family and play diverse important roles in various plant functions. However, most tomato ERFs are not characterized. In this study, we showed that expression of an uncharacterized member of tomato ERF-IX subgroup, ERF68, was significantly induced by treatments of different bacterial pathogens, ethylene (ET) and salicylic acid (SA), but only slightly induced by bacterial mutants defective in the type III secretion system (T3SS) or non-host pathogens. ERF68-GFP fusion protein localized in the nucleus. Transactivation and electrophoretic mobility shift assays (EMSA) further showed that ERF68 was a functional transcriptional activator and bound to the GCC-box. Moreover, transient overexpression of ERF68 led to spontaneous lesions in tomato and tobacco leaves and enhanced expression of genes involved in ET, SA, jasmonic acid (JA) and hypersensitive response (HR) pathways, while silencing of ERF68 increased tomato susceptibility to two incompatible Xanthomonas spp. These results reveal the involvement of ERF68 in effector-triggered immunity (ETI) pathway. To identify ERF68 target genes, chromatin-immunopreciptation combined high-throughput sequencing (ChIP-seq) was performed. Among the confirmed target genes, a few genes involved in cell death or disease defense were differentially regulated by ERF68. Our study demonstrates function of ERF68 in positively regulating hypersensitive cell death and disease defense by modulating multiple signaling pathways, and provides important new information on the complex regulatory function of ERFs.
Subjects
Tomato
ERF
cell death
disease
defense
Type
thesis
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