Phytopathology. 2014 Jun;104(6):614-23. doi: 10.1094/PHYTO-09-13-0268-R.
Incorporation of plant defense activators is an innovative approach to development of an integrated strategy for the management of turfgrass diseases. The effects of salicylic acid (SA), benzothiadiazole (BTH, chemical analog of SA), jasmonic acid (JA), and ethephon (ET, an ethylene-releasing compound) on development of gray leaf spot in perennial ryegrass (Lolium perenne L.) caused by Magnaporthe oryzae were evaluated. Gray leaf spot disease incidence and severity were significantly decreased when plants were treated prior to inoculation with SA, BTH, and partially by ET but not by JA. Accumulation of endogenous SA and elevated expression of pathogenesis-related (PR)-1, PR-3.1, and PR-5 genes were associated with inoculation of plants by M. oryzae. Treatment of plants with SA enhanced expression levels of PR-3.1 and PR-5 but did not affect the PR-1 level, whereas BTH treatment enhanced relative expression levels of all three PR genes. Microscopic observations of leaves inoculated with M. oryzae revealed higher frequencies of callose deposition at the penetration sites in SA- and BTH-treated plants compared with the control plants (treated with water). These results suggest that early and higher induction of these genes by systemic resistance inducers may provide perennial ryegrass with a substantial advantage to defend against infection by M. oryzae.
将植物防御激活剂纳入其中是开发草坪病害综合管理策略的一种创新方法。本研究评估了水杨酸（SA）、苯并噻二唑（BTH，SA 的化学类似物）、茉莉酸（JA）和乙烯释放化合物（ET）对稻瘟病菌引起的多年生黑麦草灰斑病发展的影响。在接种前用 SA、BTH 和部分 ET 处理植物可显著降低灰斑病的发病率和严重度，但 JA 处理则无效。植物接种稻瘟病菌后内源 SA 的积累和病程相关（PR）-1、PR-3.1 和 PR-5 基因的表达水平升高。用 SA 处理植物可增强 PR-3.1 和 PR-5 的表达水平，但不影响 PR-1 水平，而 BTH 处理则增强了这三个 PR 基因的相对表达水平。对接种稻瘟病菌的叶片进行显微镜观察发现，与对照（用水处理）植物相比，SA 和 BTH 处理植物的穿透部位有更高频率的胼胝质沉积。这些结果表明，这些基因通过系统抗性诱导剂的早期和更高诱导可能为多年生黑麦草提供对抗稻瘟病菌感染的显著优势。
