Overexpression of the Apple (Malus × domestica) MdERF100 in Arabidopsis Increases Resistance to Powdery Mildew

Abstract

APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors play important roles in plant development and stress response. Although AP2/ERF genes have been extensively investigated in model plants such as Arabidopsis thaliana, little is known about their role in biotic stress response in perennial fruit tree crops such as apple (Malus × domestica). Here, we investigated the role of MdERF100 in powdery mildew resistance in apple. MdERF100 localized to the nucleus but showed no transcriptional activation activity. The heterologous expression of MdERF100 in Arabidopsis not only enhanced powdery mildew resistance but also increased reactive oxygen species (ROS) accumulation and cell death. Furthermore, MdERF100-overexpressing Arabidopsis plants exhibited differential expressions of genes involved in jasmonic acid (JA) and salicylic acid (SA) signaling when infected with the powdery mildew pathogen. Additionally, yeast two-hybrid and bimolecular fluorescence complementation assays confirmed that MdERF100 physically interacts with the basic helix–loop–helix (bHLH) protein MdbHLH92. These results suggest that MdERF100 mediates powdery mildew resistance by regulating the JA and SA signaling pathways, and MdbHLH92 is involved in plant defense against powdery mildew. Overall, this study enhances our understanding of the role of MdERF genes in disease resistance, and provides novel insights into the molecular mechanisms of powdery mildew resistance in apple.

GWAS Reveals a Novel Candidate Gene CmoAP2/ERF in Pumpkin (Cucurbita moschata) Involved in Resistance to Powdery Mildew

“…Likewise, all the remaining four SNPs (SNP 1, 2, 4, and 6) were nonsynonymous mutations and resulted in substituting different amino acid residues at AA105, AA302, AA321, AA402, respectively ( Figure 3 A,B). In line with these findings, many earlier reports substantiated the roles of the AP2/ERF transcription factor family genes for mediating the pathogen responses in diverse plant species [ 43 , 44 , 45 ].…”

“…The AP2/ERF group of transcription factors is the largest group of plant-specific TFs. This group is widely known for its multifarious roles, including plant development and biotic and abiotic stress regulation [ 1 , 43 , 44 ]. A recent report revealed that the C. moschata genome contains 212 AP2/ERF genes [ 68 ].…”

“…A recent report revealed that the C. moschata genome contains 212 AP2/ERF genes [ 68 ]. In the past, several ERF genes were characterized in the model land plant Arabidopsis thaliana for their functional association with plant pathogenic responses against Alternaria alternata , Botyosphaeria dothidea , Pseudomonas syringae PV tomato DC3000 (PstDC3000), Ralstonia solanacearum , and tobacco mosaic virus (TMV) [ 43 ]. Likewise, the ERF genes from one species were functionally characterized in other plant species for their roles in enhancing tolerance to pathogen attack.…”

“…Likewise, the ERF genes from one species were functionally characterized in other plant species for their roles in enhancing tolerance to pathogen attack. For instance, overexpression of Malus domestica ERF 100 (MdERF100) in A. thaliana [ 43 ]. Gossypium hirsutum ERF gene (GhB301) in Nicotiana benthamiana [ 69 , 70 ], Artemisia annua ORA (AaORA) gene in A. thaliana [ 71 ], Glycine max ERF5 (GmERF5) in soybean [ 45 ], and tobacco stress-induced gene 1 (Tsi1) in hot pepper [ 72 ] enhanced transgenic line tolerance to different pathogens.…”

Contrasting Roles of Ethylene Response Factors in Pathogen Response and Ripening in Fleshy Fruit

“…Overexpression of MdERF11 in apple ( Malus domestica Borkh) callus cells significantly increased their resistance to B. dothidea infection, whereas silencing MdERF11 resulted in reduced resistance. MdERF11 increases plant defense against B. dothidea by stimulating the SA biosynthesis pathway [ 122 ], and MdERF100 (in Malus domestica Gala) interacts directly with MdbHLH92 to mediate resistance to powdery mildew by upregulating the JA and SA signaling pathways [ 123 ]. Overexpression of VvERF1 in grape ( Vitis vinifera Kyoho) fruits reduced the susceptibility to B. cinerea infection [ 124 ].…”