AaERF1 Positively Regulates the Resistance to Botrytis cinerea in Artemisia annua

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.

Natural products – modifying metabolite pathways in plants

“…Moreover, two A. annua methyl jasmonate-responsive transcription factors, regulating expression of the first two artemisinin biosynthetic genes, were recently identified [39], as well as an A. thaliana MYC factor, involved in transcriptional control of two C15-TPS genes [40]. Further reports established a tight correlation between the A. annua ERF/AP2 transcription factor AaORA and the expression of three artemisinin pathway genes [41]. Understanding transcriptional regulation of terpenoid biosynthesis has considerable implications for pathway manipulation in cell or tissue cultures of medicinal plants.…”

“…To date, however, the results of transcription factor overexpression in periwinkle hairy roots or cell lines remain inconclusive [43,44]. Concurrently, enhanced expression of AaORA in A. annua resulted in an approximately 50% increase in artemisinin accumulation, and a 35% boost in DHAA (dihydroartemisinic acid) content, respectively [41]. This limited augmentation of product levels suggests involvement of additional factors.…”

Metabolic engineering of terpene biosynthesis in plants using a trichome‐specific transcription factor MsYABBY5 from spearmint (Mentha spicata)

“…Few TFs have been reported from other plants that are involved in regulating terpene biosynthesis. They are Artemisia annua , AaWRKY1, AaERF1, AaERF2, AaORA1 and AabZIP1 (Lu et al ., ; Ma et al ., ; Yu et al ., ; Zhang et al ., ), cotton GaWRKY1 (Xu et al ., ), TaWRKY1 from Taxus chinensis (Wang et al ., ), rubber EREBP1 and HbWRKY1 (Chen et al ., ; Zhou et al ., ) and OsTGAP1 in rice (Miyamoto et al ., ).…”

A novel Gossypium barbadense ERF transcription factor, GbERFb, regulation host response and resistance to Verticillium dahliae in tobacco

“…Wounding is a common damage caused by biotic and abiotic stress, which could activate defense-related gene to prevent further damage. Some ERFs were also regulated by wounding, such as AaERF (Lu et al 2013) and LeERF1/2/ 4 (Tournier et al 2003). Our results showed that GbERFb was obviously up-regulated at 12 h post wounding.…”