中国葡萄主要品种对葡萄座腔菌的抗性评价

采用离体有伤接种绿枝条的方法分析了我国25个葡萄主要品种对葡萄座腔菌Botryosphaeria dothidea的抗/感程度并建立了抗性分级标准。根据接种发病后的病斑长度,利用系统聚类方法鉴定不同葡萄品种对葡萄座腔菌的抗性并进行分级,建立了葡萄对葡萄座腔菌的抗性评价方法和抗性分级标准。结果表明,我国25个主要葡萄品种对葡萄座腔菌的抗性存在明显差异,‘巨峰’、‘红宝石无核’、‘藤稔’、‘红地球’、‘香妃’、‘玫瑰香’、‘巨玫瑰’、‘霞多丽’、‘龙眼’、‘西拉’、‘品丽珠’、‘贝达’、‘峰后’、‘梅鹿辄’、‘美人指’、‘赤霞珠’和‘山葡萄洛桑’等17个品种对葡萄座腔菌表现为抗病,‘弗蕾无核’、‘5BB’、‘夏黑’和‘无核白鸡心’表现为感病,而‘维多利亚’、‘牛奶’、‘矢富罗莎’和‘摩尔多瓦’表现为高感。     

Identification of grapevine marker genes for early,non‐destructive Eutypa lata infection diagnosis

Eutypa lata is the causal agent of eutypa dieback, a highly damaging trunk disease affecting all grape‐growing areas, with currently neither an efficient curative treatment nor an early non‐destructive diagnostic method. The present work was carried out to discover grapevine genes expressed in response to the presence of E. lata that could be useful to develop an early (before visible foliar symptoms) and non‐destructive (using grapevine leaves) diagnostic tool. Microarray analyses were carried out from (i) infected plants showing characteristic E. lata foliar and vascular symptoms and positive pathogen recovery from vascular lesions (S⁺R⁺), (ii) infected plants showing no symptoms (S^?R⁺), and (iii) symptomless plants with negative pathogen recovery (S^?R^?). Vineyard and greenhouse‐grown plants, naturally or artificially infected respectively, and uninoculated controls were characterized and leaf RNA was hybridized with 15k operon grapevine oligonucleotide microarrays. Among the grapevine genes differentially expressed between S^?R⁺ and S^?R^? plants in greenhouse and vineyard conditions, 10 were highlighted as robust candidate genes for diagnosis: seven were specifically involved in response to infection and three were associated with symptom absence. Five were confirmed to be effective diagnostic marker genes usable in a qRT‐PCR‐based test performed on RNA extracted from grapevine leaves cultivated in either greenhouse or vineyard conditions. Furthermore, their expression profiles in response to infection with E. lata or other major grapevine fungi (Erysiphe necator, Plasmopara viticola, Botrytis cinerea) could be distinguished. The usefulness of these genes to develop an early and non‐destructive method for diagnosis of E. lata infection is discussed with regard to the advantages and drawbacks of previous E. lata diagnostic studies.     

Widespread latent infection of Cryptostroma corticale in asymptomatic Acer pseudoplatanus as a risk for urban plantations

Sooty bark disease (SBD) caused by the pathogen Cryptostroma corticale is currently one of the risks to the population of Acer pseudoplatanus in Europe. After a number of records of symptomatic and dead trees in Prague, assessment of the latent non‐symptomatic stage of SBD was questioned as a means to forecast the health risk of the A. pseudoplatanus population. We used two methods of early detection of C. corticale in non‐symptomatic trees: cultivation from wood tissue on agar plates and a culture‐free approach based on nested PCR with newly designed species‐specific primers. The pathogen was detected in 25% of 112 examined trees from seven localities in Prague, but the disease incidence might be higher if more A. pseudoplatanus trees in Prague were included and if the crown infections were considered. The presence of C. corticale was positively correlated with discoloured wood, but its presence did not depend on the occurrence of external symptoms. Infected trees were more frequently found in groups on steep sites at higher elevations. In addition, heavier NO_x pollution combined with more paths and roads increased the incidence of C. corticale.     

Phytophthora agathidicida: research progress,cultural perspectives and knowledge gaps in the control and management of kauri dieback in New Zealand

Kauri (Agathis australis), which is one of the world's largest and longest-living conifer species, is under threat from a root and collar dieback disease caused by the oomycete pathogen Phytophthora agathidicida. The noted incidence of kauri dieback has increased in the past decade, and even trees >1000 years old are not immune. This disease has profound effects on both forest ecosystems and human society, particularly indigenous Māori, for whom kauri is a taonga or treasure of immense significance. This review brings together existing scientific knowledge about the pathogen and the devastating disease it causes, as well as highlighting important knowledge gaps and potential approaches for disease management. The life cycle of P. agathidicida is similar to those of other soilborne Phytophthora pathogens, with roles for vegetative hyphae, zoospores and oospores in the disease. However, there is comparatively little known about many aspects of the biology of P. agathidicida, such as its host range and disease latency, or about the impact on the disease of abiotic and biotic factors such as soil health and co-occurring Phytophthora species. This review discusses current and emerging tools and strategies for surveillance, diagnostics and management, including a consideration of genomic resources, and the role these play in understanding the pathogen and how it causes this deadly disease. Key aspects of indigenous Māori knowledge, which include rich ecological and historical knowledge of kauri forests and a holistic approach to forest health, are highlighted.     

苹果枝枯病病原菌鉴定及生物学特性

正苹果(Malus pumila Mill.)是世界上栽培最为广泛的水果之一,由于其生态适应性强、营养价值高、耐贮性好及供应周期长,相当多的国家都将其列为主要消费果品[1],而我国是世界上苹果种植面积最大、产量最高的国家[2]。我国苹果枝干病害以苹果轮纹病和腐烂病为主,近年来随着气候环境的改变,一些新的病害也逐渐产生。2017年7月对烟台市几个苹果果园调查时,发现一种新病害。该病害主要危害苹果枝条,产生褐色坏死病斑,严重时导致枝条枯死,发     

Mortierella species from declining Araucaria araucana trees in Patagonia,Argentina

Since 2015, Araucaria araucana, an ecologically and economically important conifer native to Argentina and Chile, has suffered an unusual partial death of the crown throughout almost all of the distribution range in Argentina. No primary pathogen or pest was evident, associated with the phenomenon. Isolates of Mortierella, a poorly studied fungal genus in Patagonia, were obtained from the margins of necrotic phloem tissue of symptomatic trees. Five species of Mortierella were isolated from affected tissues. In inoculation tests, Mortierella alpina and M. aff. basiparvispora were pathogenic to A. araucana. These species caused necrosis of phloem, leading to chlorosis, foliar desiccation and eventually death, demonstrating that Mortierellales may play a role in the decline of the tree.     

Identifying Fraxinus excelsior tolerant to ash dieback: Visual field monitoring versus a molecular marker

Ash dieback (ADB) caused by the pathogen Hymenoscyphus fraxineus is the cause of massive mortality of Fraxinus spp. in Europe. The aim of this work was to check for the presence of the molecular marker for ADB tolerance in mapped healthy‐looking F. excelsior trees, and to compare its occurrence in trees exhibiting severe ADB symptoms. Monitoring of 135 healthy‐looking F. excelsior on the island of Gotland, Sweden, showed that after 3–4 years 99.3% of these trees had 0%–10% crown damage, thus remaining in a similar health condition as when first mapped. After 5–6 years, 94.7% of these trees had 0%–10% crown damage. Molecular analysis of leaf tissues from 40 of those showed the presence of the molecular marker in 34 (85.0%) trees, while it was absent in 6 (15.0%) trees. Analysis of leaf tissues from 40 severely ADB‐diseased trees showed the presence of the molecular marker in 17 (42.5%) trees, but its absence in 23 (57.5%) trees (p < .0001). The results demonstrated that monitoring of healthy‐looking F. excelsior is a simple and straightforward approach for the selection of presumably ADB‐tolerant ash for future breeding. The cDNA‐based molecular marker revealed moderate capacity on its own to discriminate between presumably ADB‐tolerant and susceptible F. excelsior genotypes.     

Genetic diversity and aggressiveness of Erwinia psidii on Eucalyptus spp. in Brazil

The genetic variability and aggressiveness of Brazilian Erwinia psidii isolates from Eucalyptus spp. was studied and compared with reference isolates from guava (Psidium guajava). Repetitive element sequence (rep)-based PCR markers of 101 isolates from Eucalyptus spp. and five from guava showed that the populations of E. psidii displayed a relatively low genetic variability. No correlation of genetic clustering based on rep-PCR analysis with geographic origin or host of origin was observed, indicating that genome rearrangements associated with adaptation to a particular host were not detected by these molecular markers. A higher genotypic richness was detected in the Mato Grosso do Sul population, probably reflecting a pathogen dissemination associated with the recent expansion in eucalypt plantations. Wilcoxon and ANOVA tests of disease severity data indicated differences in aggressiveness among isolates and an isolate × clone interaction. The area under the disease progress curve (AUDPC) and disease severity for some isolates were significantly different between two susceptible clones tested. Notably, isolate LPF681 from guava was not able to cause disease on a susceptible Eucalyptus urophylla clone, suggesting that some co-evolution between pathogen and host has taken place. The variability in aggressiveness and virulence among isolates of E. psidii observed in this study will be important for the establishment of appropriate screening approaches to select for disease resistance.     

葡萄 VvSUC 27基因的克隆及病原响应表达分析

由葡萄座腔菌科Botryosphaeriaceae真菌引起的葡萄溃疡病(Botryosphaeria dieback)是葡萄上的主要枝干病害之一, 严重影响葡萄产业的健康发展?其中, 致病力最强的为可可毛色二孢 Lasiodiplodia theobromae ?糖转运蛋白在调节植物对病原菌的免疫过程中起着至关重要的作用, 关于葡萄中糖转运蛋白参与植物免疫机制的研究尚未见报道?本试验从‘无核白’葡萄叶片中克隆得到蔗糖转运蛋白 VvSUC 27基因, 其开放阅读框全长1 515 bp, 预测蛋白质分子量为54 kD, 理论等电点(pI)为9.58?生物信息学预测该蛋白含有12个跨膜结构?实时荧光定量PCR(qRT-PCR)分析表明:氨基环丙烷羧酸和脱落酸处理后 VvSUC 27的表达水平持续上调; 水杨酸和茉莉酸甲酯处理后, VvSUC 27的表达呈现上调表现但无规律的变化特征; 激发子chitin和flg22处理后, VvSUC 27基因信号响应快速且明显; 感病品种‘夏黑’接种可可毛色二孢后, VvSUC 27被迅速诱导, 3 h时表达量达到最高, 而后逐渐减弱?本研究将为今后阐明可可毛色二孢与葡萄互作的分子机制提供参考依据?