生长季苹果园冠层空气中斑点落叶病分生孢子飞散动态

通过对生长季苹果园冠层空气中苹果斑点落叶病菌分生孢子逐日和逐小时的捕捉，同时记载空气温度，相对湿度和降雨等气象数据，分析发现，6至7月份为整个生长季中孢子飞散的高峰期，影响孢子飞散的主要气象要素为降雨和风，一天中孢子飞散的动态是昼多夜少，9：00-22：00孢子飞散量占全天的87.2%，孢子飞散的最高峰为15：00-16：00，各小时孢子飞散与相对湿度呈显著负相关，而与温度呈显著正相关。     

山东省芍药红斑病病原菌鉴定

从山东菏泽和泰安两地感病芍药（Paeonia lactiflora Pall.）植株的叶片上进行了红斑病病原分离纯化和致病力检测,并对致病菌进行了形态学鉴定及rDNA-ITS 序列分析。研究结果表明,病样组织中可分离到两种疑似病原菌,分离比例为4.8︰1,初步鉴定为链格孢（Alternaria alternata）和细极链格孢（A. tenuissima）。进一步rDNA-ITS分析结果表明,两种病原菌5.8S rDNA及其两侧ITS区序列分别与GenBank中序列号为KF380822.1、HM467832.1的同源性最高,均为99%,由此确定两种病原菌分别为链格孢Alternaria alternata和细极链格孢A. tenuissima,其序列已在GenBank登录,登录号分别为KR912224和KR912225。因此,确定山东省芍药红斑病是由链格孢A. alternata和细极链格孢A. tenuissima两种病原菌引起的复合侵染。     

贡柑黑腐病病原菌生物学特性研究

摘要：在贡柑黑腐病病原菌分离鉴定的基础上,对其病原菌的生物学特性进行研究。结果表明,该病原菌（Alternaria citri Ellis & Everhart）在PDA培养基上生长最佳。菌丝生长和分生孢子萌发的适宜温度分别为21~30 ℃和18~30 ℃,适宜pH值分别为5~12和4~7。供试的6种碳源中,葡萄糖和可溶性淀粉较利于菌丝生长,蔗糖较利于孢子萌发;供试的6种氮源中,牛肉膏较利于菌丝生长,酵母膏较利于孢子萌发。光照条件对病原菌产孢影响不大,完全光照与光暗交替12 h较利于菌丝生长和孢子萌发。分生孢子致死温度为51 ℃水浴10 min。     

小麦链格孢叶枯病的病原学研究

 自70年代以来,在黄河中游麦区发生了一种病原菌未知的小麦叶枯病,1993年至1996年依据柯赫氏证病律进行了病原学研究。结果由陕西、甘肃和河南等省采集的田间病叶标样,发现了11个小麦链格孢(Alternaria triticina Prasada and Prabhu)分离菌株。在PCA平板上培养,该菌的初生分生孢子梗着生由(1~)2~5个孢子构成的短链,分生孢子褐黄色,宽卵球形、椭圆形,具3~8个横隔,0~5个纵隔或斜隔,分隔处缢缩,孢子体20~50 μm×10~15 μm,假喙柱形或膝状,5~47.5 μm×4~5μm。接种小麦叶片上出现长卵形、椭圆形褐色斑点,进而扩展成长条形和不规则形病斑,周边有亮黄色晕圈。严重发病常导致叶枯,叶片大部死亡。     

链格孢菌毒素对中国月季主要营养物质含量的影响

用链格孢菌毒素细交链孢菌酮酸(TeA)处理中国月季叶片后,用凯氏定氮法、烘干法、蒽酮比色法和电感偶合等离子发射光谱仪(ICP-OES)分别测定处理2、6、10、14、20 d后,处理部位叶片和位于处理叶片上方和下方的叶片中蛋白质、水分、可溶性糖和矿质元素的含量。结果表明：与健康叶片相比,用TeA处理后的叶片其蛋白质、水分和可溶性糖含量均明显下降,蛋白质含量变化较复杂,在处理6 d后,其含量显著增加,之后又随处理时间的增加而降低。蛋白质含量从208.41 mg/g降低至45.09 mg/g;水分含量从77.36%下降到69.56%,下降了7.79%;可溶性糖含量从12.58 mg/g降低到8.45 mg/g。中国月季用链格孢菌毒素TeA处理后多种矿质元素含量发生变化,Ca、Mg、K、S、P、Zn等元素含量降低,Al、Cu、Mn、Na等元素含量升高。并且TeA处理具有空间效应,对位于处理部位上方和下方的叶片的营养元素都有影响。     

一种快速、特异性检测小麦中链格孢菌（Alternaria alternata）的巢式 PCR 方法

为建立检测小麦中链格孢菌（Alternaria alternata ）的方法,从河南省小麦黑胚籽粒上分离得到7个优势 A．alternata 病原菌株,对其 rDNA 的内部转录间隔区序列（ITS）进行测序,序列比较表明,分离到的病原菌株与 GenBank 公布的 A．alternata 的 ITS 区序列一致性达到99％～100％。根据 Alternaria 属菌株（A．alternata、A．tenuis、A．tenuissima）和麦类根腐离蠕孢菌（Bipolaris sorokiniana ）的 ITS 序列比对结果,设计出1对 A．alternata 特异性引物 Aa1F/Aa1R。利用多种河南省小麦的主要病原真菌对该引物的特异性进行验证,只有在 A．alternata 中能特异性地扩增出1条443 bp 的 DNA 片段。以真菌通用引物 ITS1/ITS4为外侧引物、特异性引物Aa1F/Aa1R 为内侧引物进行巢式 PCR 扩增,能检测到 A．alternata DNA 的最低质量浓度为50 pg/μL。因此,建立的巢式 PCR 方法能够快速、特异地检测小麦中的 A．alternata。     

Occurrence of the F129L mutation in Alternaria solani populations in Germany in response to QoI application,and its effect on sensitivity

Early blight caused by Alternaria solani is a highly destructive disease of potatoes. Control of early blight mainly relies on the use of preventive fungicide treatments. Because of their high efficacy, azoxystrobin and other quinone outside inhibitors (QoIs) are commonly used to manage early blight. However, loss of sensitivity to QoIs has previously been reported for A. solani in the United States. Two hundred and three A. solani field isolates collected from 81 locations in Germany between 2005 and 2011 were screened for the presence of the F129L mutation in the cytochrome b gene; of these, 74 contained the F129L mutation. Sequence analysis revealed the occurrence of two structurally different cytb genes, which differed in the presence (genotype I) or absence (genotype II) of an intron, with genotype I being the most prevalent (63% of isolates). The F129L mutation was detected only in genotype II isolates, where it occurred in 97%. Sensitivity to azoxystrobin and pyraclostrobin was determined in conidial germination assays. All isolates possessing the F129L mutation had reduced sensitivity to azoxystrobin and, to a lesser extent, to pyraclostrobin. Early blight disease severity on plants treated with azoxystrobin was significantly higher for A. solani isolates with reduced fungicide sensitivity in the conidial germination assay compared with sensitive isolates. Data suggest an accumulation of F129L isolates in the German A. solani population over the years 2009–2011. It is assumed that the application of QoIs has selected for the occurrence of F129L mutations, which may contribute to loss of fungicide efficacy.     

Evaluation of tangerine hybrid resistance to Alternaria alternata

The Alternaria Brown Spot, caused by Alternaria alternata, is a major fungal disease in some kinds of tangerines, tangor, mandarins and pomelos. In Brazil as well as worldwide, A. alternata can cause necrosis in fruits, branches and leaves, causing substantial profit loss. In the present research, in laboratory conditions and in the field, we evaluated the resistance to the fungus, in leaves and fruits, for 22 varieties and hybrids of tangerines. To this end, we evaluated genotypes belonging to the Germplasm Bank of the Estação Experimental de Citricultura de Bebedouro. The resistant genetic materials (found in leaves and fruits) represented four varieties of clementines (Citrus clementina); six varieties of mandarins (two belonging to C. reticulata, two to C. tangerina, one to C. deliciosa and one to C. nobilis); one tangelo (C. tangerina × C. paradisi); two mandarin hybrids (one resulting from crossing C. nobilis × C. deliciosa and the other from crossing C. clementina × C. reticulata); one tangor hybrid (C. clementina) and two satsuma hybrids (C. unshiu × C. deliciosa). We also determined a relation between the inoculation of leaves and fruits. The resistance and susceptibility following inoculation in leaves and fruits supports a relationship between these organs and the physiological responses observed for the evaluated genotypes.     

马铃薯早疫病菌的分离鉴定和生物学特性研究

采用组织分离法对重庆市巫溪县马铃薯早疫病病原菌进行分离鉴定,并对该菌的生物学特性进行研究。结果表明：重庆地区马铃薯早疫病菌丝有横隔和分支|分生孢子梗单生或丛生|分生孢子倒棒状或手雷形,大小为（46.32～156.33）μm×（11.58～28.95）μm,具纵横隔膜。结合rDNA-ITS序列分析,确定为茄链格孢菌（Alternaria sonali Sorauer）。生物学特性研究表明,光照对菌丝生长影响不显著,但黑暗条件有利于产孢|菌丝生长最适温度为27～28 ℃,最适pH值为6|分生孢子萌发最适温度为30 ℃,最适pH值为7～8。营养特性研究表明,蔗糖、果糖、乳糖、麦芽糖和淀粉都比葡萄糖更有利于菌丝生长,其中蔗糖、果糖、乳糖效果较好|甘氨酸和硝态氮能促进菌丝生长,铵态氮抑制菌丝生长。     

枯草芽胞杆菌QM3防治番茄早疫病和促进幼苗生长的研究

［目的］ 枯草芽胞杆菌QM3是从青海牦牛粪中分离筛选的一株对番茄早疫病菌有显著抑菌效果的高效拮抗菌株,本文旨在进一步明确QM3对番茄早疫病的作用机制和在生物体内的防治效果。 ［方法］ 采用温室盆栽试验测定QM3发酵液对番茄早疫病的防治效果及对不同番茄品种的促生作用,并测定该菌株在番茄根际的定殖能力。［结果］ 不同处理的QM3发酵液均对番茄早疫病有明显的防治效果（p<0.05）,最高可达52.94%,且与化学农药联合使用防效更好,最高可达71.80%;经QM3发酵液处理后,番茄植株叶片数、株高及根部发育等指标有增加;此外,灌根接种QM3菌株后,根际总芽胞杆菌数量明显增加（p<0.01）。［结论］ QM3菌株是一株有益的促生根际细菌（PGPR）,具有应用于番茄早疫病生防的潜力。