AaERF1 positively regulates the resistance to Botrytis cinerea in Artemisia annua.

Xu Lu,Ling Zhang,Fangyuan Zhang,Kexuan Tang,Qian Shen,Fei Zhang,Guofeng Wang,Weimin Jiang,Dawn Arnold

doi:10.1371/journal.pone.0057657

Abstract

Plants are sessile organisms, and they can not move away under abiotic or biotic stresses. Thus plants have evolved a set of genes that response to adverse environment to modulate gene expression. In this study, we characterized and functionally studied an ERF transcription factor from Artemisia annua, AaERF1, which plays an important role in biotic stress responses. The AaERF1 promoter had been cloned and GUS staining results of AaERF1 promoter-GUS transgenic A. annua showed that AaERF1 is expressed ubiquitiously in all organs. Several putative cis-acting elements such as W-box, TGA-box and Py-rich element, which are involved in defense responsiveness, are present in the promoter. The expression of AaERF1 can be induced vigorously by methyl jasmonate as well as by ethephon and wounding, implying that AaERF1 may activate some of the defense genes via the jasmonic acid and ethylene signaling pathways of A. annua. The results of electrophoretic mobility shift assay (EMSA) and yeast one-hybrid experiments showed that AaERF1 was able to bind to the GCC box cis-acting element in vitro and in yeast. Ectopic expression of AaERF1 could enhance the expression levels of the defense marker genes PLANT DEFENSIN1.2 (PDF1.2) and BASIC CHITINASE (ChiB), and increase the resistance to Botrytis cinerea in the 35S::AaERF1 transgenic Arabidopsis. The down-regulated expression level of AaERF1 evidently reduced the resistance to B. cinerea in A. annua. The overall results showed that AaERF1 positively regulated the resistance to B. cinerea in A. annua.

Highlights

The necrotrophic fungus Botrytis cinerea causes significant economic losses throughout the world as a destructive pathogen of a broad spectrum of plant species [1]
AaERF1 is Ubiquitously Expressed in A. annua The promoter sequence of AaERF1(JQ513909)was cloned by genomic walking (Figure 1A)
To observe the expression pattern of AaERF1 in details, the AaERF1 promoter was subcloned to the pCAMBIA1391Z vector (Figure 1B) and AaERF1 promoterGUS transgenic A. annua plants were generated

Summary

Introduction

The necrotrophic fungus Botrytis cinerea causes significant economic losses throughout the world as a destructive pathogen of a broad spectrum of plant species [1]. The AP2/ERF transcription factors are one of the most important families that are involved in plant response to biotic and abiotic stresses as well as in the development of various plant species [2]. In contrast to the AP2 and RAV subfamily members, the CBF/DREB and ERF subfamily proteins contain single AP2/ERF domain [5]. The genes in the CBF/DREB subfamily play a crucial role in the resistance of plants to abiotic stresses by recognizing the dehydration responsive or cold-repeat element (DRE/CRT) with a core motif of A/GCCGAC [6]. The ERF subfamily is often involved in the response to plant stresses like pathogenesis by modulating the expression of their target genes via binding to the cis-acting element AGCCGCC, known as the GCC box in their promoters [5]

Methods

Results

Conclusion