title: Identification and utilization of a new Erysiphe necator isolate NAFU1 to quickly evaluate powdery mildew resistance in wild Chinese grapevine species using detached leaves.
abstract: The most economically important disease of cultivated grapevines worldwide is powdery mildew caused by the biotrophic fungal pathogen Erysiphe necator. To integrate effective genetic resistance into cultivated grapevines, numerous disease resistance screens of diverse Vitis germplasm, including wild species, have been conducted to identify powdery mildew resistance, but the results have been inconsistent. Here, a new powdery mildew isolate that is infectious on grapevines, designated Erysiphe necator NAFU1 (En. NAFU1), was identified and characterized by phylogeny inferred from the internal transcribed spacer (ITS) of pathogen ribosomal DNA sequences. Three classical methods were compared for the maintenance of En. NAFU1, and the most convenient method was maintenance on detached leaves and propagation by contact with infected leaves. Furthermore, controlled inoculations of En. NAFU1 were performed using detached leaves from 57 wild Chinese grapevine accessions to quickly evaluate powdery mildew resistance based on trypan blue staining of leaf sections. The results were compared with previous natural epidemics in the field. Among the screened accessions inoculated with En. NAFU1, 22.8% were resistant, 33.3% were moderately resistant, and 43.9% were susceptible. None of the accessions assessed herein were immune from infection. These results support previous findings documenting the presence of race-specific resistance to E. necator in wild Chinese grapevine. The resistance of wild Chinese grapevine to En. NAFU1 could be due to programmed cell death. The present results suggest that En. NAFU1 isolate could be used for future large-scale screens of resistance to powdery mildew in diverse Vitis germplasms and investigations of the interaction between grapevines and pathogens.
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Yu-Rong
authors.initials: YR
authors.lastname: Gao
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Yong-Tao
authors.initials: YT
authors.lastname: Han
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Feng-Li
authors.initials: FL
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Ya-Juan
authors.initials: YJ
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China.
authors.forename: Yue-Jin
authors.initials: YJ
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology for Arid Areas and College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Yangling 712100, China. Electronic address: wenyq@nwsuaf.edu.cn.
authors.forename: Ying-Qiang
authors.initials: YQ
authors.lastname: Wen
mesh_terms: D000818:Animals; D017209:Apoptosis; D001203:Ascomycota / Q000302:isolation & purification / Q000502:physiology* / Q000648:ultrastructure; D060467:Disease Resistance; D010802:Phylogeny; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D018515:Plant Leaves / Q000276:immunology / Q000382:microbiology / Q000648:ultrastructure; D027843:Vitis / Q000276:immunology* / Q000382:microbiology / Q000648:ultrastructure
keywords: Detached leaves; Disease reaction; Erysiphe necator; Powdery mildew; Resistance; Wild Chinese grapevine