Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, Nova Scotia, Canada.
Engage Agro Corporation, Guelph, Ontario, Canada.
Pestic Biochem Physiol. 2018 Nov;152:122-130. doi: 10.1016/j.pestbp.2018.09.007. Epub 2018 Sep 23.
Phosphite (Phi)-based fungicides, such as the commercial product Phostrol™, are widely used in potato late blight control. However, the Phi translocation efficiency and the efficacy against pathogen are less discussed. In this study, the Phi concentration were quantified by high performance ion chromatography (HPIC) and the Phi translocation efficiency in potato tissues was evaluated using potato cultivar Russet Burbank with foliar application of the Phostrol solution both under greenhouse and field conditions. In the greenhouse trials, it was found that Phi was translocated from leaves to roots within 3 h and its concentration was significantly increased in the roots 24 h after the Phostrol application. In the field trials, the application rate of Phostrol affected the Phi translocation in potato tubers. To assess the efficacy of Phi against P. infestans, both the inhibition and infection tests were carried out. In the inhibition tests, three most common strains of P. infestans in Canada (US-8, US-23 and US-24) were inoculated on pea agar containing different levels of Phi. In the infection tests, both of detached leaves and whole tubers that received Phi were infected by the three strains of P. infestans. The in vitro tests indicated that the US-8 strain is the most tolerant whereas the US-23 strain is the most sensitive to Phi. Also, the in vivo tests demonstrated the dose-dependent translocation of Phi in potato leaves and tubers decreased the severity of infection by P. infestans. Moreover, potential defense mechanisms related to salicylic acid (SA) and jasmonic acid (JA) pathways that might be activated by Phi were also explored. Overall, the results of the study provided evidences that high Phi translocation efficiency encouraged late blight suppression in potato production.
亚磷酸盐（Phi）类杀菌剂，如市售产品 Phostrol™，广泛用于防治马铃薯晚疫病。然而，Phi 的转运效率和对病原菌的防治效果讨论较少。本研究采用高效离子色谱法（HPIC）定量测定 Phi 浓度，并采用叶面喷施 Phostrol 溶液的 Russet Burbank 马铃薯品种，在温室和田间条件下评估 Phi 在马铃薯组织中的转运效率。在温室试验中，发现 Phi 在 3 小时内从叶片转运到根部，Phostrol 处理后 24 小时，根部 Phi 浓度显著增加。在田间试验中，Phostrol 的施用量影响马铃薯块茎中 Phi 的转运。为评估 Phi 对晚疫病菌的防治效果，进行了抑菌和侵染试验。抑菌试验中，将加拿大三种最常见的晚疫病菌（US-8、US-23 和 US-24）接种于含不同 Phi 浓度的豌豆琼脂上。侵染试验中，用三种晚疫病菌分别感染接种 Phi 的离体叶片和完整块茎。体外试验表明，US-8 菌株对 Phi 最耐受，而 US-23 菌株对 Phi 最敏感。体内试验还表明，Phi 在马铃薯叶片和块茎中的剂量依赖性转运降低了晚疫病菌的侵染严重程度。此外，还探索了可能与水杨酸（SA）和茉莉酸（JA）途径相关的潜在防御机制，这些机制可能被 Phi 激活。总体而言，该研究结果提供了证据表明，高 Phi 转运效率有助于抑制马铃薯生产中的晚疫病。
