Myb转录因子广泛参与调控植物生长发育以及应对环境胁迫,但有关其对晚疫病抗性调控机制的研究较少.本研究从本氏烟草中克隆获得一个含Myb-like结构域的蛋白编码基因,命名为NbMybl.该基因开放阅读框全长为753 bp,编码250 aa.实时荧光定量PCR(qPCR)结果显示NbMybl受致病疫霉(Phytophthora infestans)侵染诱导表达.亚细胞定位表明NbMybl定位在植物细胞核和细胞质中.利用病毒诱导的基因沉默技术,发现沉默NbMybl能够明显降低本氏烟草对致病疫霉的抗性.分析比较NbMybl沉默和非沉默对照烟草株系应对P.infestans侵染的转录组数据,发现差异表达基因(Dif-ferentially expressed genes,DEGs)8486个,其中上调基因 4202 个,下调基因 4284个.使用 KEGG(Kyoto Encyclopedia of Genes and Genomes)数据库进行基因富集分析,发现鉴定得到的DEGs中共有373个参与植物-病原菌互作,308个参与植物激素信号转导,216个参与植物MAPK信号途径.推测这些DEGs可能与沉默NbMybl降低本氏烟草抗病性有密切关联.qPCR检测部分DEGs的表达,发现其表达趋势与转录组数据一致.本研究为阐明NbMybl参与对抗致病疫霉侵染提供了理论依据.
Cloning and functional analysis of the Nicotiana benthamiana NbMybl gene related to late blight resistance
Myb transcription factors play important roles in the regulation of various biological processes in plants.However,the molecular mechanism underlying their roles in regulating late blight resistance remains elu-sive.Here,we report the cloning of NbMybl,a Myb-like gene from Nicotiana benthamiana,which has an open reading frame of 753 bp and encodes a protein of 250 aa.NbMybl contains a Myb-like DNA-binding domain.Real-time quantitative PCR(qPCR)revealed that NbMybl was induced by infection with Phytophthora infestans.Subcellular localization analysis showed that NbMybl is located in both the nucleus and the cytoplasm.Silencing of NbMybl by virus-induced gene silencing(VIGS)significantly increased the susceptibility of plants to P.infes-tans.Transcriptome profiling by RNA sequencing identified 8468 differentially expressed genes(DEGs)with fold change ≥ 2 and FDR＜0.01 between NbMybl silenced and non-silenced control lines in response to P.in-festans infection,and the result of RNA-seq was further validated by qPCR with 10 randomly selected DEGs.KEGG(Kyoto Encyclopedia of Genes and Genomes)enrichment analysis revealed that a total of 373 DEGs were involved in plant-pathogen interaction,308 DEGs and 216 DEGs were involved in MAPK signaling path-way and plant hormone signal transduction,respectively.We speculated that these DEGs might be closely related to the reduced resistance of NbMybl-silenced N.benthamiana lines to P.infestans.Our study provides valuable insights into the molecular mechanisms of NbMybl in regulating resistance to P.infestans.
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