Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea.
Environmental Microbiology Research Team, Nakdonggang National Institute of Biological Resources (NNIBR), Sangju 37242, Korea.
Genes (Basel). 2020 Aug 26;11(9):1000. doi: 10.3390/genes11091000.
The pinewood nematode (PWN) causes pine wilt disease, which results in substantial economic and environmental losses across pine forests worldwide. Although systemic acquired resistance (SAR) is effective in controlling PWN, the detailed mechanisms underlying the resistance to PWN are unclear. Here, we treated pine samples with two SAR elicitors, acibenzolar--methyl (ASM) and methyl salicylic acid (MeSA) and constructed an in vivo transcriptome of PWN-infected pines under SAR conditions. A total of 252 million clean reads were obtained and mapped onto the reference genome. Compared with untreated pines, 1091 and 1139 genes were differentially upregulated following the ASM and MeSA treatments, respectively. Among these, 650 genes showed co-expression patterns in response to both SAR elicitors. Analysis of these patterns indicated a functional linkage among photorespiration, peroxisome, and glycine metabolism, which may play a protective role against PWN infection-induced oxidative stress. Further, the biosynthesis of flavonoids, known to directly control parasitic nematodes, was commonly upregulated under SAR conditions. The ASM- and MeSA-specific expression patterns revealed functional branches for myricetin and quercetin production in flavonol biosynthesis. This study will enhance the understanding of the dynamic interactions between pine hosts and PWN under SAR conditions.
松材线虫（PWN）引起松材萎蔫病，导致全球范围内的松林遭受重大的经济和环境损失。尽管系统性获得抗性（SAR）在控制 PWN 方面非常有效，但对 PWN 抗性的详细机制尚不清楚。在这里，我们用两种 SAR 诱导剂——苯并噻二唑-7-甲酯（ASM）和甲基水杨酸（MeSA）处理松树样本，并在 SAR 条件下构建了感染 PWN 的松树的体内转录组。共获得 2.52 亿条清洁reads，并映射到参考基因组上。与未处理的松树相比，ASM 和 MeSA 处理后分别有 1091 和 1139 个基因差异上调。其中，650 个基因对两种 SAR 诱导剂表现出共表达模式。这些模式的分析表明，光呼吸、过氧化物酶体和甘氨酸代谢之间存在功能联系，这可能对 PWN 感染诱导的氧化应激起到保护作用。此外，黄酮类化合物的生物合成，已知其直接控制寄生线虫，在 SAR 条件下普遍上调。ASM 和 MeSA 的特异性表达模式揭示了类黄酮生物合成中杨梅素和槲皮素产生的功能分支。本研究将增强对 SAR 条件下松树宿主与 PWN 之间动态相互作用的理解。
