广西黑皮冬瓜疫病的病原菌鉴定及其生物学特性

 Isolate PD1 of Phytophthora was isolated from diseased black pericarp wax gourd in Guangxi in 2005. The morphological and biological characters of the isolate were examined, and its sequence of ribosomal DNA-ITS was analyzed. The range of growth temperature of the isolate was 10-37℃ and the optimal one was 31℃. The pathogen was sensitive to 10 mg/kg of malachite green, and its ability for starch utilization was weak. A wide host range of the pathogen was confirmed by artificial inoculation. The sizes of sporangia were (37.5-71.7) μm×(20.8-47.5) μm (av. 55.0 μm×30.4 μm). Microcycle conidiation of the pathogen was observed. The pathogen was identified as Phytophthora drechsleri Tucker based on its morphological and biological characters as well as ribosomal DNA-ITS sequence.     

阔叶十大功劳炭疽病初报

 A new leaf spot disease of Mahonia healei was found in Guangxi China, which was one of the limitations for the growth of M. healei. Based on the morphology, pathogenicity and the analysis of sequences of ribosome rDNA-ITS, the pathogen of M. healei anthracnose disease was identified as Colletotrichum gloeosporioides (Penz.)Sacc.     

2008年我国部分麦区小麦白粉病菌群体对温度的敏感性

 The sensitivity of 113 isolates of wheat powdery mildew (Blumeria graminis f. sp. tritici) sampled from 6 provinces or cities in 2008 to temperature was tested by detached leaf segment method with setting up 5 different temperatures indoor. The results showed the mean ET₅₀ (which represents the temperature that is required to obtain 50% of the maximum effect) of all isolates tested was 23.02℃. ET₅₀ values of 17.70% isolates were more than 24℃. The highest and the lowest ET₅₀ of isolates were 25.22℃ and 19.42℃, respectively. There were a certain differences for isolates sensitivity to temperature among different provinces or cites. It was also found that when temperature increased during 22-26℃, the latent period of isolates prolonged, and the latent period of different isolates was different at the same temperature, too. These results will provide a reference for the oversummering division of wheat powdery mildew, as well as the effect of climate to the disease.     

草莓轻型黄边病毒3'末端序列多态性研究

 The 930 bp segment in 3' terminal region of Strawberry mild yellow edge virus(SMYEV) genome was amplified by 3' rapid amplification of cDNA ends(RACE).Ten Chinese isolates were sequenced,and 7 of them were the same.Nucleotide and amino acid identities and phylogenesis were analyzed between Chinese isolates and 24 isolates from other regions of the world.Sequence analysis of the 878 nt stretch within 3' terminal region of SMYEV genome showed that nucleotide acid identities ranged from 79.5% to 100%,deduced amino acid sequences of coat protein gene identity were 86.4% to 100%.Phylogenetic analysis showed that all isolates of SMYEV fell into four clades.To a certain extent,the clades were related with the geological distribution of SMYEV.Chinese isolates SY01 and SY04 lay in the same clade with European and American isolates,but formed a small separate branch.Isolates SY03 and SY02,derived from Fragaria×ananassa cv.Changhong-2 and F.pentaphylla respectively,had a far relationship with other isolates and fell into one clade.They were likely to be the special isolates that existed only in China.     

甘蔗黄叶病毒复制酶基因的克隆及序列分析

 The gene of RNA-dependent RNA polymerase (RdRP) was cloned by RT-PCR from Sugarcane yellow leaf virus-Fuzhou isolate (CHN-FJ1) and then cloned into pMD18-T vector. The sequence showed that the fragment comprised 1 212 nucleotides including part gene of ORF1 and ORF2. The ORF2 was involved the RdRP gene consisted of 995 nucleotides and encoded putative protein of 331 amino acids. Compared the nucleo-tide sequence and encoded putative protein of CHN-FJ1 with the other isolates from different countries, they shared the homology above 92.0%. Phylogenetic tree suggested that the sixteen isolates were classified into four types according to the amino acid sequence of the RdRP. One of the groups contained CHN-FJ1 and the other isolates from China, American, Brazil, Australia and Colombia;however, there was the closest relation between CHN-FJ1 and BRA-YL1 isolate from Brazil.     

水稻纹枯病菌菌核上的真菌和细菌种类及其对水稻纹枯病菌生长的影响

 A total of 136 fungal and 86 bacterial isolates were isolated from the sclerotia of Rhizoctonia solani,collected from three different sources.These fungal isolates were identified as the following 12 genera:Alternaria,Aspergillus,Cladosporium,Coniothyrium,Curvularia,Gliocladium,Fusarium,Metarhizium,Peni-cillium,Phoma,Phytophthora and Trichoderma.Some isolates of Trichoderma and Gliocladium were found to inhibit the growth of R.solani strongly in vitro.Among the 86 bacterial isolates,20 of them could inhibit the growth of R.solani,whereas 5 isolates were found to promote the growth of mycelia and the formation of sclerotia of R.solani.These bacterial isolates with antagonistic actives to R.solani were identified as Bacillus and Pseudomonas.     

云南甘蔗宿根矮化病调查及种茎温水处理脱菌效果检测

 Based on the specific primer from the nucleotide sequences between 16S-23S rDNA, Polymerase chain reaction (PCR) approach for detecting Leifsonia xyli subsp. xyli (Lxx) was established. The approach was applied to detect Lxx from 30 cultivars collected from two main sugar cane producing areas in Yunnan and 10 hot-water treatment samples. The results showed that 80% of the cultivars were infected by Lxx and hot-water treatment was proved to be an efficient measure to control but not completely eliminate Lxx in sugar cane tissues. The PCR products amplified from six infected cultivars were cloned and sequenced, six sequences were acquired and analyzed. It indicated that the six sequences were identical and showed 100% similarity with the isolates from Brazil, Australia and Fujian, and 99.54% with the isolate from Louisiana.     

茄科蔬菜立枯丝核菌的融合群鉴定

 Sixty-five samples were collected from rhizosphere soil, hot pepper and tomato plants showing damping-off, root rot and stem rot in Taian, Shouguang of Shandong province and Zhouzhi, Taibai of Shaanxi province. Thirty-nine Rhizoctonia solani isolates were obtained from these samples. The results of anastomosis group (AG) identification and sequence analysis of 5.8S rDNA-ITS of the isolates showed that thirty-six isolates (92.3%) belonged to AG-4, while only three (7.7%) belonged to AG-5. The isolates of AG4 could further be divided into two subgroups of AG4-HG-Ⅰ and AG4-HG-Ⅲ. The 5.8S rDNA-ITS sequences of the selected isolates of the two subgroups had the 99%-100% identity with standard isolates of AG4-HG-Ⅰ and AG4-HG-Ⅲ (from GenBank). Among the analyzed isolates, AG4-HG-Ⅰ subgroup was the dominant with the frequency of 79.5%. Subgroup AG-4-HG-Ⅲ with the frequency of 12.8% was the second. This is the first report that subgroup AG4-HG-Ⅲ of R. solani isolated from Solanaceae vegetable crops in China.     

安徽省烟草黑胫病菌的交配型及其地理分布研究

 Total 69 isolates of Phytophthora nicotianae var. nicotianae were isolated and identified from tobacco black shank samples collected from different areas of Anhui province, and mating types of the oomycete were investigated by the method of partnership culture in vitro on L-tryptophan medium with β-sitosterol. The results showed that A2 mating type was the predominant in isolates of P. nicotianae var. nicotianae, next was A₀ mating type, A₁ and other mating types were not observed. It was suggested that sexual reproduction of P. nicotianae var. nicotianae might not take place frequently, and Anhui province might not be the original center of P. nicotianae var. nicotianae. The results indicated further that mating type geographical distribution of P. nicotianae var. nicotianae in Anhui province was in line with that in China. In addition, the significance of the test results and the possible reason for A₁ mating type being absent were discussed.     

荔枝炭疽病菌生物学特性的研究

 本文主要研究了温度、湿度、pH值、光照、营养对荔枝炭疽病菌(Colletotrichum gloeosporioides Penz.)生长、产孢和孢子萌发的影响。该菌菌丝生长的温度范围为8~38℃,最适28℃;产生分生孢子的温度范围为12~36℃,最适28~32℃;分生孢子萌发的温度范围为8~38℃,最适28~32℃。在pH 3~10的范围内该菌均能生长和产孢,菌丝生长最适pH 5~6;产生分生孢子最适pH3~4,分生孢子萌发最适pH 6~7。分生孢子在饱和湿度或水滴中萌发快,相对湿度低于85%时不能萌发。光照处理对该菌生长发育无显著性影响。葡萄糖、蔗糖、麦芽糖、果糖对分生孢子萌发有促进作用。分生孢子的致死温度为50℃ 10 min,菌丝体的致死温度为60℃ 30 min。     

链霉菌ZZSP-7的鉴定及其对草莓炭疽病的防效

为获得草莓炭疽病菌胶孢炭疽菌的优良拮抗菌,以草莓种植基地的土壤为拮抗菌来源,通过室内测定不同分离物对草莓炭疽病菌的抑菌活性,筛选抑菌率最高的菌株,在此基础上对所筛菌株进行分类鉴定,并评价其抑菌谱和防效。结果表明,从土壤中分离获得42株拮抗菌,筛选出5株对胶孢炭疽菌具有明显抑制作用的菌株。其中,菌株ZZSP-7的抑菌作用最强,5 d后的抑菌带宽达17.6 mm。经形态、生理生化及16S rDNA基因系统发育分析,确认菌株ZZSP-7为链霉菌Streptomyces sp.。菌株ZZSP-7抑菌谱广,对多种植物病原菌均具有良好的抑菌效果。盆栽试验结果表明,在盆栽中菌株ZZSP-7对“红颜”和“甜查理”两个品种草莓炭疽病菌的防效分别为78.64%和82.81%,具有进一步开发和利用的前景。     

橡胶树两种叶部病害拮抗木霉T008的筛选、鉴定及室内防效评价

采用平板稀释法从海南橡胶园16份根际土壤中分离获得6株拮抗木霉,通过对峙培养、非挥发性和挥发性物质及几丁质酶活测定,从中筛选出一株对橡胶树胶孢炭疽菌Colletotrichum gloeosporioides和多主棒孢菌Corynespora cassiicola均有较好抑制作用的菌株T008;采用分子生物学鉴定方法,...     

木薯炭疽病拮抗木霉菌筛选与室内防效研究

本文对木薯炭疽病的病原进行鉴定,筛选和鉴定拮抗该病原物的木霉菌,并测定了其室内防效.通过组织分离法和柯赫氏法则,明确了引起木薯炭疽病的病原菌为胶孢炭疽菌Colletotrichum gloeosporioides;采用平板对峙试验,从15株木霉菌中筛选获得3株对胶孢炭疽菌具有较强抑制作用的木霉菌LG004-52、LS0...     

辣椒炭疽病菌对嘧菌酯的敏感性测定

 从江苏和海南省随机采集分离获得45个辣椒炭疽病菌单孢菌株,根据孢子形态鉴定其病原菌为Colletotrichum gloeosporioides和C.capsici,其中C.gloeosporioides占总菌株数的64.4%.筛选出甘油琼脂(AEA)培养基和水琼脂(WA)培养基,分别作为产孢法和孢子萌发法测定辣椒炭疽病菌对嘧菌酯敏感性的适宜培养基.通过孢子萌发法测定2种病原菌45个菌株对嘧菌酯的敏感性范围在0.009~0.091μg/mL之间,平均EC₅₀为(0.047±0.040)μg/mL.其中29个C.gloeosporioides菌株和16个C.capsici菌株的平均EC₅₀值分别为(0.051±0.047)μg/mL和(0.041±0.024)μg/mL.研究发现旁路氧化酶抑制剂水杨肟酸(SHAM)对嘧菌酯抑制分生孢子萌发有协同增效作用,且嘧菌酯抑制辣椒炭疽病菌菌丝生长的能力较弱.     

建兰炭疽病拮抗放线菌的筛选及防治效果

为筛选获得对建兰炭疽病菌胶孢炭疽菌具有良好抑菌效果的放线菌，以野生山地兰花表层土壤为分离样本，从土壤样品中分离获得25株放线菌，初筛出6株对建兰炭疽病菌胶孢炭疽菌具有明显抑制作用的菌株，其中菌株SVFJ-07的抑菌效果最好，抑菌率达83.64%。经形态特征、生理生化特征及16S rDNA序列分析，确认菌株SVFJ-07为酒红链霉菌。该菌对多种真菌具有良好的抑菌效果。对建兰炭疽病的室内防效为70.06%，田间防效66.27%～68.54%。可见，酒红链霉菌SVFJ-07对建兰炭疽病菌胶孢炭疽菌具有较好的拮抗作用，生防应用前景良好。     

海南岛芒果果实真菌潜伏侵染的研究

 近五年来,通过对外表无任何症状和无伤口的健康芒果果实进行了分离培养、接种及贮藏试验证明了在我国海南岛地区,芒果也存在着真菌的潜伏侵染。除发现了两种炭疽菌外,还发现为色二孢菌和交链孢菌等真菌的潜伏侵染。在不同气候类型区,潜伏侵染的真菌种群及数量有差异。潜伏侵染的真菌大量存活于果皮和果蒂部位。     

红掌胶胞炭疽菌的分子检测

 胶胞炭疽菌是引起红掌炭疽病的病原菌。根据GenBank中炭疽属不同种的ITS序列差异,设计了胶胞炭疽菌的特异性引物E1/E2,由此建立的PCR检测体系可以从38个胶胞炭疽菌菌株中扩增得到329 bp的特异性条带,而扩增其它近似或相关菌株时没有相应的特异性条带。该检测体系对胶胞炭疽菌基因组DNA的扩增灵敏度达到10 pg。将引物E1/E2与ITS区通用引物进行套式PCR扩增后,检测灵敏度至少提高10 000倍。当土中胶胞炭疽菌分生孢子达到200个/g土时可检测出。进一步利用此检测体系对携带病原菌的灌溉水、发病组织进行检测,均能快速稳定地检测出病原菌。     

影响柿树炭疽菌孢子萌发、附着胞形成及致病性的环境因子

 在凹玻片上测定了不同浓度的葡萄糖溶液对柿树炭疽菌(Colletotrichum gloeosporioides)的分生孢子萌发和附着胞形成率的影响,结果表明:分生孢子萌发率随葡萄糖浓度升高而增加,但附着胞形成率下降,芽管长度增加,附着胞的直径几乎没有变化;随着时间的延长,孢子萌发率和附着胞形成率都有所增加。不同pH对分生孢子萌发和附着胞形成率的影响结果显示,分生孢子在pH 2.0~9.0的溶液中可以萌发,并产生附着胞;最适分生孢子萌发和附着胞形成的pH是在5.0~6.0。不同pH处理的致病试验结果说明。在23℃时病斑在pH 4.0~8.0条件下都可产生;致病试验结果也发现,17℃时,pH6.0处理能发病,但不形成分生孢子团,pH 5.0处理不发病;15℃时,pH 5.0和pH 6.0的处理都不能发病。温度对菌丝生长的影响显示,菌落生长最适温度是25℃左右,高温抑制菌落生长。寄主表面侵染结构扫描电镜观察结果表明,芽管长度变化很大,芽管可以纵向沿着脊或沟延伸,也可横向通过脊沟;附着胞均在沟底或近底部形成。