Pine wilt disease causes cavitation around the resin canals and irrecoverable xylem conduit dysfunction
Pine wilt disease causes cavitation around the resin canals and irrecoverable xylem conduit dysfunction
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DOI：
10.1093/jxb/erx417
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发表时间：
2018-01
影响因子：
6.9
通讯作者：
K. Yazaki;T. Takanashi;N. Kanzaki;Masabumi Komatsu;D. Levia;Daisuke Kabeya;H. Tobita;M. Kitao;A. Ishida
中科院分区：
文献类型：
--
作者：
K. Yazaki;T. Takanashi;N. Kanzaki;Masabumi Komatsu;D. Levia;Daisuke Kabeya;H. Tobita;M. Kitao;A. Ishida
松树枯萎病（PWD）引起的不可逆水力功能障碍的生理机制尚不清楚。我们采用低温扫描电子显微镜（cryo-SEM）调查的时间和空间变化的水分分布在2年生的日本黑松幼苗的主茎的松材线虫（PWNs）感染。我们的实验是专门设计来比较幼苗之间的水分关系进行以下水处理和PWN组合：（i）浇水良好与长期干旱（无PWN）;和（ii）浇水良好与PWN与PWN（共四个处理）水胁迫。低温扫描电镜成像观察记载了受PWD影响的幼苗木质部管胞中斑片状空化的发展。随着干旱程度的加深，主茎木质部中有缘纹孔的纹孔膜随着水势的降低而被吸出，但没有木质部空化现象，表明管胞之间可能存在水力分割。这是第一项研究，以最终证明爆炸性和不可逆的空化发生在周围的液压脆弱的树脂管与PWD的进展。我们的研究结果提供了一个更全面的了解压力对植物-水的关系，最终可能更好地保护树木从PWD，并协助培育树木更耐受PWD。
Physiological mechanisms of irreversible hydraulic dysfunction in seedlings infected with pine wilt disease (PWD) are still unclear. We employed cryo-scanning electron microscopy (cryo-SEM) to investigate the temporal and spatial changes in water distribution within the xylem of the main stem of 2-year-old Japanese black pine seedlings infested by pine wood nematodes (PWNs). Our experiment was specifically designed to compare the water relations among seedlings subjected to the following water treatment and PWN combinations: (i) well-watered versus prolonged drought (no PWNs); and (ii) well-watered with PWNs versus water-stressed with PWNs (four treatments in total). Cryo-SEM imaging observations chronicled the development of patchy cavitations in the xylem tracheids of the seedlings influenced by PWD. With the progression of drought, many pit membranes of bordered pits in the xylem of the main stem were aspirated with the decrease in water potential without xylem cavitation, indicating that hydraulic segmentation may exist between tracheids. This is the first study to demonstrate conclusively that explosive and irreversible cavitations occurred around the hydraulically vulnerable resin canals with the progression of PWD. Our findings provide a more comprehensive understanding of stressors on plant-water relations that may eventually better protect trees from PWD and assist with the breeding of trees more tolerant to PWD.