Effects of postharvest treatments on recovery of Xanthomonas citri subsp. citri in infected grapefruit leaves

Studies were conducted to evaluate treatments that reduce recovery of Xanthomonas citri subsp. citri (Xcc) in infected grapefruit leaves. To investigate effects of temperature (0, 10, 40, and 50 °C), disinfectant (none or Pro-San), and treatment duration (0, 2, 10, and 20 min) on survival of Xcc in vitro, a split–split plot experimental design was utilized. Recovery of Xcc in vitro in the absence of Pro-San decreased with increasing treatment duration at 50 °C but not at temperatures <50 °C. Xcc in vitro was not detected after any treatment combination involving Pro-San. Decontamination of grapefruit leaves infected with Xcc in relation to disinfectant (none or Pro-San), temperature (0, 10, 40, 45, and 50 °C), treatment duration (0, 2, 5, 10, and 20 min), and assessment time (0, 2, 7, and 14 days post treatment [dpt]) was examined using a split–split–split plot design. Reductions in Xcc recovery generally increased with increasing treatment duration and temperature, and they were greater for treatments involving Pro-San. To examine the general trend of increased Xcc recovery with increasing dpt, nonlinear mixed regression analysis was used to fit a monomolecular model to relative Xcc recovery data. Results indicated that increases in relative Xcc recovery after 14 dpt were insignificant and unsubstantial. Treatment at 45 °C for 20 min or 50 °C for ≥5 min resulted in leaf tissue damage in some instances; in two cases, tissue damage was observed on untreated leaves 14 dpt. Experiments were conducted to investigate the relationships of tissue damage with leaf age and location of tissue damage in relation to point of inoculation. Tissue damage was observed on only the youngest, most supple leaves, and its localization did not appear to be related to naturally occurring citrus canker lesions or artificial inoculation sites. Results from these studies may be useful in formulation of future regulatory policies regarding trade of citrus foliage, especially those used as condiments.     

柑橘抗溃疡病转录因子CsAP2-09互作蛋白筛选与分析

以前期获得的柑橘抗溃疡病的正调控转录因子基因 CsAP2-09 超表达植株为材料，利用 GST融合蛋白沉降技术（GST pull-down）联合液相色谱串联质谱（LC–MS/MS）方法筛选并鉴定 CsAP2-09的互作蛋白。首先原核表达并纯化 GST-CsAP2-09 作为诱饵蛋白，然后与 CsAP2-09 超表达植株叶片总蛋白孵育、洗脱后进行 SDS-PAGE 验证，最后进行 LC–MS/MS 鉴定。得到 17 个互作蛋白，将蛋白进行注释、GO 分析、KEGG 分析，发现其中 5 个可能与植物抗病相关（如过氧化氢酶 Cs3g27280）。构建这 17个蛋白的互作网络，其中 14 个蛋白的互作关系得到已有数据的支持。对 CsAP2-09 与互作蛋白的共表达分析发现 CsAP2-09 超表达引起了 16 个蛋白表达上调和 1 个蛋白表达下调。     

In vitro growth of Gremmeniella abietina isolates (European race) at different temperatures

The mycelial growth of 24 isolates of types A and B of Gremmeniella abietina (Lagerb.) Morelet, collected in northern Finland and the Kola peninsula, Russia, was studied on malt agar plus pine needle extract at 18°C and 5°C. Great variation occurred within both types, and the results suggest that several isolates per stand are needed to represent one local isolate, if responses of G. abietina mycelia are studied on artificial media.     

桐庐县板栗溃疡病发生现状及防治对策

介绍了板栗溃疡病的病害种类、病原、症状和发生规律,提出了适地适树、良种壮苗造林、加强栗园管理、增强树势、及时清除病原、抓好防治的防治对策。     

Une méthode d'inoculation pour l'évaluation précoce du comportement du Mélèze vis a vis du Lachnellula willkommii

An inoculation method for early assessment of Larch resistance to Lachnellula willkommii . Efficiency of inoculation with mycelium and ascospores was compared on 4–13-year-old Larix decidua. Only mycelium induced high infection rates. Mycelial inoculum was contained in colonized sorghum-straw pieces and was introduced in 1 mm diameter holes drilled through the bark in April/May. The main infection was detectable as early as 18 months after inoculation and infection rate increased only until the 28th month after inoculation. The susceptibility of the branches did not depend on their age, their position in the trees, the age of inoculated shoots or the management of the trees. Susceptibility was even for the 1–2-yr-old parts of the stems and branches but the oldest parts of the stems were less susceptible. The inoculation method was effective for detecting differences in susceptibility among trees. One seedling from the Alps, and clone 3001–00035, which is the mother of resistant hybrids, were the least susceptible.     

鲁甸苹果腐烂病发生规律及药剂防治试验初报

苹果腐烂病的发生和蔓延，与苹果园的管理、树势强弱、年龄、坡向、林地生长状况、土壤质地等环境因子有着极为密切的关系。其综合防治措施有：调整产量、合理施肥、合理灌水、树体喷药、外科刮除病斑及涂药防治。     

树木溃疡病菌主要类群系统地位及茶蔗子葡萄座腔菌的种内一致性

报道利用微卫星引物[（GT）n、（CGA）n、（CCA）n、（GAA）n、（CAA）n、（GA）n]和小卫星引物M13进行的葡萄座腔菌属、盾壳霉属和疡壳孢属真菌的随机扩增微卫星多态性PCR（RAMs-PCR）遗传多样性结果：42个参试菌株被分为4个RAMs分类群；其中22个葡萄座腔菌属菌株和6个小穴壳菌属菌株分布于这4个类群中；RAMs分类群Ⅰ，Ⅱ，Ⅳ仅仅由葡萄座腔菌属和小穴壳菌属菌株构成，部分茶蔗子葡萄座腔菌，4个贝伦格葡萄座腔菌和所有的盾壳霉属和疡壳孢属菌株构成了RAMs分类群Ⅲ。研究结果显示通过形态学确定的茶蔗子葡萄座腔菌种内具有遗传不一致性．形态学上一致的28个茶蔗子葡萄座腔菌菌株识别为4个不同的表观群；造成苹果轮纹病菌和苹果干腐病菌的贝伦格葡萄座腔菌菌株与部分茶蔗子葡萄座腔菌在分子水平上非常相似；研究结果亦显示盾壳霉属与疡壳孢属真菌有着较近的系统关系。     

杨树溃疡病测报方法的初步研究

根据杨树溃疡病的发生规律,在测报期间内,病情指数(Dis)与相应时期的菌量(F_1、F_2、F_3)、积温(CT)、温湿比(TH)、温雨比(TR)及湿雨比(HR)有着密切的相关关系。应用多元统计方法建立的多元线性回归预测模型:Dis=19.0-2.8(F_3)~(1/2)+0.1F_1+0.0015(F_2)~3+4.15TH-0.042(CT)~(1/2)-0.4HR+3.5TR,可以预测一个月后的发病情况,模型经实际病情验证,有较高的准确性。     

农约“农抗120”田间应用技术研究

研究了农药“农抗120”对枯萎病的作用方式,认为以浸种和灌根方法使药剂进入植物体,可显著降低枯萎病的发病率,并据此研究了防治瓜、菜枯萎病的关键技术.通过田间试验,提出了对果树腐烂病、作物叶部病害等不同类型病害的防治策略和技术.     

一株拮抗番茄溃疡病菌的海洋放线菌的分类鉴定及活性测定

从大连海域采集的海泥样品中分离得到1株放线菌菌株PH33,根据其形态特征、培养特征、生理生化特性和16S rRNA序列分析结果,鉴定该菌株为小链霉菌(Streptomyces parvus)。采用琼脂块法和牛津杯法测定了菌株PH33对番茄溃疡病菌的拮抗能力。结果表明:抑菌活性物质在100℃水浴加热、pH 2条件下的抑菌活性均不变,pH 12条件下抑菌活性稍有下降;紫外线照射不影响其抗菌活性。说明该菌株在预防和控制番茄溃疡病的发生及危害方面有潜在的应用价值。