Table_1_Trichoderma-Induced Ethylene Responsive Factor MsERF105 Mediates Defense Responses in Malus sieversii.DOCX

Trichoderma can induce plant hormone signal pathways mediating plant defenses, resulting in broad-spectrum resistance to phytopathogens. Herein, Malus sieversii seedlings were treated with Trichoderma biofertilizer and/or Alternaria alternata f. sp. mali, and transcriptome analysis revealed significant differential expression. There was a high similarity between the transcriptome expression profiles of Trichoderma-induced and A. alternata-infected M. sieversii samples for genes related to jasmonic acid (JA), ethylene, and salicylic acid (SA) signaling pathways. Additionally, Trichoderma biofertilizer activated numerous disease-resistant genes (ERF, NAC, bHLH, and STK) and defense response genes (DRP, ABC, and HSP). Among transcription factors, members of the ERF family were the most differentially expressed (18 ERFs), indicating that they may be closely related to defense responses. Among ERFs, differential expression of MsERF105 was the most significant (upregulated 27.6-fold compared to controls). MsERF105 was heterologously expressed in PdPap poplar (Populus davidiana × Populus alba var. pyramidalis Louche), and following infection with A. alternata (Aal), transgenic PdPap-MsERF105s plants displayed lower malondialdehyde (downregulated 41.4%) and reactive oxygen species (ROSs) levels, and higher reductase activities, especially superoxide dismutase (SOD; upregulated 77.5% compared to PdPap-ROK2 plants). Furthermore, the lesion areas of PdPap-MsERF105s leaves were significantly smaller (0.2%) than those of PdPap-ROK2 leaves (∼26.0%), and the cell membrane integrity was superior for PdPap-MsERF105s leaves. Thus, MsERF105 enhanced the resistance of PaPap poplar to Aal, presumably because MsERF105 activates the expression of PR1 and PDF1.2. In conclusion, Trichoderma biofertilizer modulated the differential expression of numerous disease resistance genes and defense response genes in M. sieversii in response to pathogen attack, and MsERF105 played important roles in this process.木霉菌（Trichoderma）可诱导介导植物防御反应的植物激素信号通路，进而赋予植物对植物病原菌的广谱抗性。本研究中，研究人员以塞威氏苹果（Malus sieversii）幼苗为实验材料，分别施加木霉菌生物肥、苹果链格孢苹果专化型（Alternaria alternata f. sp. mali），或联合施加两种试剂，转录组分析结果显示各组样本存在显著差异表达基因。木霉菌诱导与苹果链格孢侵染的塞威氏苹果样本中，与茉莉酸（JA）、乙烯、水杨酸（SA）信号通路相关的基因的转录组表达谱高度相似。此外，木霉菌生物肥可激活大量抗病基因（ERF、NAC、bHLH及STK）与防御反应基因（DRP、ABC及HSP）。在转录因子家族中，ERF家族成员的差异表达程度最为显著（共18个ERF基因），表明其可能与植物防御反应密切相关。在ERF家族基因中，MsERF105的差异表达最为显著，较对照组上调27.6倍。研究人员将MsERF105异源表达于PdPap杨（Populus davidiana × Populus alba var. pyramidalis Louche）中，接种苹果链格孢（A. alternata, Aal）后，转MsERF105的PdPap杨植株的丙二醛（malondialdehyde）与活性氧（ROS）水平均显著降低（丙二醛下调41.4%），还原酶活性则显著提升，其中超氧化物歧化酶（SOD）活性较PdPap-ROK2植株上调77.5%。进一步检测发现，转MsERF105的PdPap杨叶片病斑面积仅为0.2%，显著小于PdPap-ROK2植株叶片的约26.0%，且转基因组叶片的细胞膜完整性更佳。综上，MsERF105可增强PdPap杨对苹果链格孢的抗性，推测其机制为MsERF105激活了PR1与PDF1.2基因的表达。最终，本研究证实木霉菌生物肥可调控塞威氏苹果中大量抗病基因与防御反应基因的差异表达以响应病原菌侵染，而MsERF105在该过程中发挥了重要作用。