Yu Wen Qing, Li Peng, Yan Feng Chao, Zheng Gui Ping, Liu Wen Zhi, Lin Wen Xi, Wang Yi, Luo Zhi Qing
College of Life Sciences, Shangrao Normal University, Shanrao, 334001, Jiangxi, China.
Heilongjiang Academy of Land Reclamation Sciences, Harbin, 150038, China.
Rice (N Y). 2021 Nov 4;14(1):91. doi: 10.1186/s12284-021-00532-6.
Protein elicitors can induce plant systemic resistance to pathogens. In an earlier study, we cloned an EsxA gene from the plant growth-promoting rhizobacterium Paenibacillus terrae NK3-4 and expressed it in Pichia pastoris. In addition to being important for the pathogenicity of animal pathogens, EsxA can also induce an immune response in animals. While, we found the exogenously expressed EsxA has the activity of elicitor, which can trigger hypersensitive response and reactive oxygen species burst in leaves as well as enhanced rice plant growth. The effects of EsxA on seedling blight (Fusarium oxysporum) resistance and gene transcription, including pathogenesis-related (PR) genes in rice were evaluated. The germination rate was 95.0% for seeds treated with EsxA and then inoculated with F. oxysporum, which was 2.8-times higher than that of F. oxysporum-infected control seeds that were not treated with EsxA (Con). The buds and roots of EsxA-treated seedlings were 2.4- and 15.9-times longer than those of Con seedlings. The plants and roots of seedlings dipped in an EsxA solution and then inoculated with F. oxysporum were longer than those of the Con seedlings. Theplant length, number of total roots, and number of white roots were respectively 23.2%, 1.74-times, and 7.42-times greater for the seedlings sprayed with EsxA and then inoculated with F. oxysporum than for the Con seedlings. The EsxA induction efficiency (spray treatment) on seedling blight resistance was 60.9%. The transcriptome analysis revealed 1137 and 239 rice genes with EsxA-induced up-regulated and down-regulated transcription levels, respectively. At 48 h after the EsxA treatment, the transcription of 611 and 160 genes was up-regulated and down-regulated, respectively, compared with the transcription levels for the untreated control at the same time-point. Many disease resistance-related PR genes had up-regulated transcription levels. The qPCR data were consistent with the transcriptome sequencing results. EsxA triggered rice ISR to seedling blight and gene differential transcription, including the up-regulated transcription of rice PR genes. These findings may be relevant for the use of EsxA as a protein elicitor to control plant diseases.
蛋白质激发子可诱导植物对病原体产生系统抗性。在早期研究中，我们从促进植物生长的根际细菌地衣芽孢杆菌NK3 - 4中克隆了EsxA基因，并在毕赤酵母中表达。EsxA除了对动物病原体的致病性很重要外，还能在动物体内诱导免疫反应。同时，我们发现外源表达的EsxA具有激发子活性，可引发叶片中的过敏反应和活性氧爆发，以及促进水稻植株生长。评估了EsxA对水稻抗枯萎病（尖孢镰刀菌）的效果以及对包括病程相关（PR）基因在内的基因转录的影响。用EsxA处理后再接种尖孢镰刀菌的种子发芽率为95.0%，比未用EsxA处理的尖孢镰刀菌感染对照种子（Con）高2.8倍。经EsxA处理的幼苗的芽和根分别比Con幼苗长2.4倍和15.9倍。用EsxA溶液浸泡后再接种尖孢镰刀菌的幼苗的地上部分和根比Con幼苗长。喷施EsxA后再接种尖孢镰刀菌的幼苗的株高、总根数和白根数分别比Con幼苗高23.2%、1.74倍和7.42倍。EsxA对枯萎病抗性的诱导效率（喷雾处理）为60.9%。转录组分析显示，分别有1137个和239个水稻基因的转录水平在EsxA处理后上调和下调。在EsxA处理48小时后，与未处理对照在同一时间点的转录水平相比，分别有611个和160个基因的转录上调和下调。许多与抗病性相关的PR基因转录水平上调。qPCR数据与转录组测序结果一致。EsxA引发了水稻对枯萎病的诱导系统抗性以及基因差异转录，包括水稻PR基因的转录上调。这些发现可能与将EsxA用作控制植物病害的蛋白质激发子有关。
