Late blight caused by the oomycete Phytophthora infestans is the major yield-threatening disease in potato production. An isolate of the photosynthetic bacterium Rhodopseudomonas palustris, GJ-22, was previously evaluated for its ability to promote the growth and enhance the immune response of solanaceous plants. In the present study, GJ-22 was shown to significantly repress disease symptom development caused by P. infestans in potato tubers. Curzate (cymoxanil plus mancozeb), a widely used fungicide with high activity against P. infestans, was selected for use in combination with GJ-22. The sensitivity of GJ-22 to the fungicides cymoxanil and mancozeb was tested. The growth of GJ-22 was unaffected by up to 100 mg l⁻¹ cymoxanil or 50 mg l⁻¹ mancozeb in photosynthetic medium. In greenhouse and field experiments, the combined application of GJ-22 and curzate resulted in better disease control than the use of either agent alone. In addition, treatment with 1 × 10⁷ CFU ml⁻¹ GJ-22 plus 700 mg l⁻¹ curzate showed synergistic effects in the field trial. Our results highlight the potential to control potato late blight with the combination of R. palustris strain GJ-22 and curzate, providing environmentally friendly protection with a reduced level of fungicide application.

中文翻译：

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光合细菌Phodopseudomonas palustris GJ-22菌株和杀真菌剂的组合对马铃薯晚疫病的综合防治

由卵菌疫霉菌引起的晚疫病是马铃薯生产中主要的威胁产量的疾病。先前已评估了光合作用细菌大红假单胞菌（Rhodopseudomonas palustris）GJ-22的分离物促进植物生长和增强茄科植物免疫反应的能力。在本研究中，GJ-22被证明可以显着抑制马铃薯块茎中致病疫霉引起的疾病症状的发展。选择Curzate（cymoxanil加mancozeb），一种对付致病疫霉的高活性的广泛使用的杀菌剂，与GJ-22结合使用。测试了GJ-22对杀菌剂cymoxanil和mancozeb的敏感性。GJ-22的生长不受高达100 mg l ^-1的影响在光合作用培养基中使用cymoxanil或50 mg l ^-1 mancozeb。在温室和田间试验中，与单独使用任何一种药剂相比，GJ-22和curzate的组合施用可以更好地控制疾病。此外，在田间试验中，用1×10 ⁷  CFU ml ^-1 GJ-22加700 mg l ^-1的curzate处理显示出协同作用。我们的研究结果突出显示了结合使用R. palustris菌株GJ-22和curzate来控制马铃薯晚疫病的潜力，从而通过减少杀菌剂的使用量提供了对环境友好的保护。