Pine wood nematodes (PWNs: Bursaphelenchus xylophilus) infect pine trees and cause serious pine wilt disease. Eastern white pine (Pinus strobus) has resistance to PWN. However, the detailed defense mechanisms of P. strobus against PWN are not well known. When P. strobus plants were infected with PWNs, the accumulation of stilbenoids, dihydropinosylvin monomethyl ether (DPME) and pinosylvin monomethyl ether (PME), were increased remarkably. DPME and PME had the high nematicidal activity. Interestingly, the nematicidal activity of the two compounds was resulted in a developmental stage-dependent manner. PME was more toxic to adult PWNs than juveniles, whereas DPME was found more toxic to juvenile PWNs than the adults. The genes involved in PME and DPME biosynthesis such as phenylalanine ammonia-lyase (PAL), 4-coumarate-CoA ligase (4CL), pinosylvin synthase (STS), and pinosylvin O-methyltransferase (PMT) were isolated using de novo sequencing of the transcriptome in P. strobus. In addition, transcription factors (bHLH, MYB and WRKY) related to stilbene biosynthesis were isolated. qPCR analyses of the selected genes (PAL, 4CL, STS, and PMT) including transcription factors (bHLH, MYB and WRKY) revealed that the expression level of the selected genes highly enhanced after PWN infection. Our results suggest that pinosylvin-type stilbenoid biosynthesis is highly responsive to PWN infection and plays an important role in PWN resistance of P. strobus trees.

中文翻译：

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松材线虫感染后松果tro中松果酚丁酯的积累和相关基因表达的增加。

松木线虫（PWN：Bursaphelenchus xylophilus）感染松树并引起严重的松萎病。东部白松（Pinus strobus）对PWN具有抗性。但是，P。strobus对PWN的详细防御机制尚不为人所知。当P. strobus植物被PWNs感染时，stilbenoids，二氢pinosylvin单甲基醚（DPME）和pinosylvin单甲基醚（PME）的积累显着增加。DPME和PME具有较高的杀线虫活性。有趣的是，这两种化合物的杀线虫活性是以发育阶段依赖性的方式产生的。PME对成年PWN的毒性比少年大，而DPME对成年PWN的毒性比成年大。参与PME和DPME生物合成的基因，例如苯丙氨酸解氨酶（PAL），4-香豆酸酯-CoA连接酶（4CL），松果体合成酶（STS）和松果体O-甲基转移酶（PMT）是通过对杆状线虫转录组的从头测序来分离的。另外，分离了与二苯乙烯生物合成有关的转录因子（bHLH，MYB和WRKY）。对包括转录因子（bHLH，MYB和WRKY）在内的所选基因（PAL，4CL，STS和PMT）的qPCR分析表明，PWN感染后所选基因的表达水平大大提高。我们的结果表明，pinosylvin型stilbenoid生物合成对PWN感染高度敏感，并在P. strobus树的PWN抗性中发挥重要作用。对包括转录因子（bHLH，MYB和WRKY）在内的所选基因（PAL，4CL，STS和PMT）的qPCR分析表明，PWN感染后所选基因的表达水平大大提高。我们的研究结果表明，pinosylvin型Stilbenoid生物合成对PWN感染高度敏感，并在P. strobus树的PWN抗性中发挥重要作用。对包括转录因子（bHLH，MYB和WRKY）在内的所选基因（PAL，4CL，STS和PMT）的qPCR分析表明，PWN感染后所选基因的表达水平大大提高。我们的结果表明，pinosylvin型stilbenoid生物合成对PWN感染高度敏感，并在P. strobus树的PWN抗性中发挥重要作用。