云南地区月季白粉病发生及抗性鉴定

Occurrence and resistance identification of rose powdery mildew in Yunnan

【目的】明确不同月季品种资源对白粉病的抗性并筛选抗性资源,为防控月季白粉病和抗病月季品种培育提供理论依据。【方法】在云南地区月季生长的主要时期(5、8和11月),对国家林草植物新品种昆明测试站(嵩明)资源圃674份月季品种田间白粉病自然发病和抗性情况进行调查,每个品种随机选取5株调查病斑占叶面的百分率,根据病情指数进行抗性评价;采集大丰收月季白粉病新鲜病样(SM),对其进行分离纯化并观察其形态特征;提取月季白粉病基因组DNA并进行PCR扩增;采用NCBI将月季白粉病ITS序列与不同白粉病病原种进行BLAST同源比对,并基于该序列相似性构建不同寄主白粉病系统发育进化树;进行月季白粉病病原菌回接,对月季离体接种病原菌后进行抗性鉴定。【结果】对674份月季品种3个季节的田间白粉病自然抗性调查结果表明,春季(5月)表现为抗性的月季品种有211个,其中77个品种高抗,81个品种抗病,53个品种中抗,分别占11.42%、12.02%和7.86%;夏季(8月)表现为抗性的月季品种有129个,其中6个品种高抗,25个品种抗病,98个品种中抗,分别占0.89%、3.71%和14.54%;秋季(11月)表现为抗性的月季品种有120个,其中7个品种高抗,53个品种抗病,60个品种中抗,分别占1.04%、7.86%和8.90%。BLAST同源比对及系统发育进化树结果显示,SM菌株的基因片段与Podosphaera pannosa基因相似性均在99%以上,SM菌株与来自不同区域白粉菌AB525939.1(蔷薇)、DQ139429.1(月季)和KF571742.1(月季)的亲缘关系最近,月季白粉菌具有高度专性寄生的特点;对每个等级3个品种共18个月季品种的离体叶片人工接种结果表明,人工离体接种结果与田间抗性表现一致。【结论】月季白粉病田间抗性主要受遗传影响,大部分供试月季品种资源易感白粉病;云南地区春季月季植株的抗性等级高于夏季和秋季;筛选出榴花秋舞、姜乳酒、金色庆典、紫虎、巴西诺和丰花玫瑰6个高抗品种,可为月季白粉病抗性基因挖掘和抗病月季品种培育提供抗性种质。

【Objective】The purpose of the study was to identify the resistance of different rose variety resources to powdery mildew and screen resistant varieties,so as to provide theoretical basis for the prevention and control of rose powdery mildew and the breeding of resistant rose varieties.【Method】In the main growth period(May,August and No-vember)of rose in Yunnan,the natural incidence and resistance of powdery mildew in 674 rose varieties in the resource nursery of the national forestry and grassland plant new variety Kunming test station(Songming)were investigated.Five plants were randomly selected from each variety to investigate the percentage of disease spots on the leaf surface,and the resistance was evaluated according to the disease index.The fresh disease samples of rose powdery mildew(SM)were col-lected from Grand Gala,and they were isolated and purified.The morphological characteristics were observed.The ge-nomic DNA of rose powdery mildew was extracted and amplified by PCR.The ITS sequence of rose powdery mildew was aligned with the BLAST homology of different powdery mildew pathogens by NCBI,and the phylogenetic evolutionary tree of different hosts of powdery mildew was constructed based on the sequence similarity.Then the pathogen of rose powdery mildew was inoculated back and the resistance of rose was identified after in vitro inoculation of pathogen.【Re-sult】The results of the survey on the natural resistance of 674 rose varieties in the field to powdery mildew in three sea-sons showed that there were 211 rose varieties that showed resistance in spring(May),of which 77 varieties were highly resistant,81 varieties were resistant,and 53 varieties were moderately resistant,accounting for 11.42%,12.02%,7.86%respectively.In summer(August),there were 129 rose varieties showing resistance,of which 6 varieties were highly re-sistant,25 varieties were resistant,and 98 varieties were moderately resistant,accounting for 0.89%,3.71%and 14.54%respectively.In autumn(November),there were 120 varieties of rose showing resistance,including 7 highly resistant va-rieties,53 resistant varieties and 60 moderately resistant varieties,accounting for 1.04%,7.86%and 8.90%respectively.The results of BLAST homologous alignment and phylogenetic evolutionary tree showed that the gene fragments of SM strain had more than 99%similarity with the genes of Podosphaera pannosa.The SM strain was most closely related to the powdery mildew pathogen AB525939.1(rosebush),DQ139429.1(rose)and KF571742.1(rose)from different re-gions.Rose powdery mildew pathogen had the characteristics of highly obligate parasitism.The results of artificial inocu-lation of isolated leaves of 18 rose varieties(3 varieties of each grade)showed that the results of artificial inoculation in vi-tro were consistent with the field resistance phenotype.【Conclusion】The field resistance of rose powdery mildew is mainly affected by genetics,and most of the tested rose variety resources are susceptible to powdery mildew.The resis-tance level of plants in spring in Yunnan is higher than that in summer and autumn.Six highly resistant varieties are screened out,including Autumn Pomegranate Flower,Ginger Syllabub,Golden Celebration,Purple Tiger,Bassino and Fenghua Rose,which can provide resistant germplasms for the exploration of powdery mildew resistance genes in rose and the cultivation of disease-resistant rose varieties.