葡萄对霜霉病抗性机理初探

经田间自然鉴定、接种鉴定及室内离体接种鉴定结果表明：葡萄对霜霉病抗性与品种叶内的含水量、可滴定酸、还原糖、淀粉、水解氨基酸、游离氨基酸含量无显著相关，与叶背气孔密度、气孔开闭程度也无相关，而外施高浓度蔗糖及邻苯二酚却显著降低霜霉菌的致病力。     

鲜食葡萄品种对霜霉病的抗性及抗病机理研究

采用田间自然发病调查，田间接种鉴定和离体葡萄叶圆片室内接种鉴定鲜食葡萄品种对霜霉病的抗性及其抗性机理研究表明，品种间对霜霉病的抗性存在显著差异。可依感病病级分为三类，低感品种有“z工伊豆”、“奥林匹亚”、“山东早红”、“森田尼”、“早玛瑙”。几乎所有的无核品种均高感霜霉病，葡萄对霜霉病的抗性与叶内可滴定酸、还原糖、游离氨基酸含量无显著相关，与叶背气也密度、气孔开度也无相关，而外施高浓度邻苯二酚却显著降低了霜霉病发病程度。     

水稻品种与水稻细菌性条斑病菌的互作机制

水稻叶片接种3d后，水稻细菌性条斑病菌开始在叶片上大量增殖；接种10d后，病菌数量开始保持相对的稳定，但感病品种上的菌量比抗病品种上的菌量在10倍左右，病斑在接种后第3d开始出现，接种10d以后，病斑在感病品种上能继续快速发展，而在抗病品种上开始受到抑制，通过对抗病和感病品种叶片上的气孔观测发现，感病品种的气孔密度和气孔长度一般都较抗病品种大，相关分析表明，气孔长度理发师品种抗性相关。接种后对PAL酶的活性测定结果表明，PAL酶的活性与品种抗性呈负相关关系。     

萝卜对芜菁花叶病毒的抗性和其叶内游离氨基酸含量的关系

 以6份抗感芜菁花叶病毒病的萝卜品种为材料,探讨了萝卜在不同叶龄期的抗病性以及不同品种的抗病性和叶内游离氨基酸含量的关系,分析了萝卜在幼苗期的抗病性和接种芜菁花叶病毒后20天时病叶和对照叶游离氨基酸含量比值的相关性,调查了接种芜菁花叶病毒后抗感病萝卜品种叶内游离氨基酸含量的变化情况。结果表明:抗病品种叶内含有较高的蛋氨酸,感病品种的含量较低;子叶期后,萝卜叶内天冬氨酸、蛋氨酸、脯氨酸及总游离氨基酸含量的迅速提高和抗病性的迅速增強呈平行关系;接种芜菁花叶病毒后,病叶蛋氨酸、酪氨酸含量和健叶差异不明显,其它各种氨基酸含量均有不同程度的上升。文中还对氨基酸作为抗性鉴定标准及鉴定的适宜时间进行了讨论。     

烟草叶片接种野火病菌后蛋白质表达差异

为了解烟草受野火病菌侵染后蛋白质表达变化情况,探讨烟草品种的抗病机制,本研究对烟草抗病品种‘K346’叶片进行人工接种,在接种后0～72h内分9次在接种点周围取无病原菌叶片组织提取叶片总蛋白,利用双向电泳技术分析接种处理叶片与未处理叶片的蛋白质表达差异,并选取6个减量表达蛋白点和4个增量表达蛋白点进行MALDI-TOF-MS质谱分析及数据库搜索鉴定,结果表明,6个减量表达蛋白包括参与植物呼吸代谢途径的ATP合成酶CF1α亚基、ATP合成酶CF1α链以及参与植物能量代谢循环途径的1,5-二磷酸核酮糖羧化酶/加氧酶相关蛋白;4个增量表达蛋白包括参与植物氨基酸代谢途径的谷氨酰胺合成酶、参与糖类和碳循环相关途径的高等植物光系统II氧复合物中Psbp A链蛋白、叶绿体景天庚酮糖-1,7-二磷酸酯酶和光捕获叶绿素a/b结合蛋白。经过蛋白质功能分析,推测烟草是通过加速植株生长、促进抗病相关糖和蛋白的表达、增强氨基酸代谢以及植株自身蛋白的修复等方式来提高抗病性。     

葡萄品种对霜霉病抗性鉴定的生化指标研究

 通过盆栽接种和田间自然发病鉴定,从22个供试葡萄品种中鉴定筛选到1个高抗霜霉病的品种超藤和8个中抗品种饭刚黑、信浓乐、弗雷无核、黑蜜、优选皮奥萘、高妻、京秀、峰后。相关性分析表明,22个供试葡萄品种接种前和接种后2d,PPO、PAL活性和CAT比活性与霜霉病病情指数呈极显著负相关,SOD活性与霜霉病病情指数相关不显著。PPO、PAL活性和CAT比活性与葡萄品种对霜霉病的抗性呈极显著正相关,可利用这3种酶的活性作为葡萄品种霜霉病抗性鉴定的辅助评价指标。     

生姜抗姜瘟病品种资源鉴定及其抗病生化机制

为鉴定生姜抗姜瘟病品种并明确其抗病生化机制,采用茎基部注射法和土壤灌根法接种测试22个生姜品种对姜瘟病的抗性水平,以高抗品种CDZIN012和高感品种CDZIN064为材料接种假茄科雷尔氏菌Ralstonia pseudosolanacearum,观察接种后抗、感品种的叶片气孔参数、蜡质含量等组织结构的变化,测定接种后过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)、过氧化氢酶(catalase,CAT)、超氧化物歧化酶(superoxide dismutase,SOD)活性,O₂^-、H₂O₂含量及病程相关蛋白几丁质酶和β-1,3-葡聚糖酶活性的变化。结果显示,22个生姜品种抗性差异明显,其中表现为高抗、中抗、轻抗、感病和高感的品种分别为1、4、4、7和6个;茎基部注射法接种后生姜植株发病更稳定,更适合生姜品种抗性鉴定;感病后抗病品种叶片气孔密度为36.8个/mm²,比感病品种少(46.9个/mm²),...     

油菜菌核病抗性鉴定方法的比较及抗源的筛选

采用已报道的七种油菜菌核病抗性鉴定方法,在同一条件下对两个感病和两个抗病品种进行鉴定比较。结果表明:草酸浸根(叶)法用于白菜型油菜鉴定效果不好;不同生育期的油菜对菌核病抗性有差异,应该以花期鉴定为主,苗期鉴定为辅;在花期以麦粒叶腋接种、琼脂块叶腋接种和牙签茎杆接种,接种后发病程度依次为牙签>麦粒>琼脂块;三种花期接种方法与大田接种鉴定的结果呈显著正相关(r>0.8000),这三种方法均能有效反映抗、感品种的差异,其中花期牙签茎杆接种法与大田接种鉴定法相关性达极显著水平(r=0.9140)。根据抗性鉴定方法比较的结果,选用花期牙签茎杆接种法,以中油821为对照,对四川农业大学油菜研究中心G1自交系的44份油菜育种材料进行鉴定、筛选,得到12份高抗材料,其中有5份材料的抗性极显著高于对照。     

烟草品种抗青枯病鉴定中相关因素分析

用烟草青枯病t1菌株对G3、红花大金元等品种分别作不同接种方法、不同菌量、不同年份和不同生育期接种试验以及与黄瓜花叶病（CMV）交叉接种试验，结果表明，参试品种在烟株旺长初期，用切根灌菌液接种与病区自然鉴定之间对青枯病抗性呈极显著正相关（r=0.9855)，接种体浓度以10^8scfu/ml为宜，不同抗感品种在不同年份重复鉴定中表现出不同程度的抗性波动，用相对抗病指数评价品种抗性，可减少误差。参试18个品种不同生育期与t1菌株的互作反应，分为苗感成株期抗病型和全期感病型两类。烟株生长初期交叉接种黄瓜花叶病毒（CMV）与青枯病菌明显减轻青枯病病情，但干扰了抗病性鉴定，查清了上述影响因素后，可以组装一套规范化的烟草品种抗青枯病筛选鉴定模式。     

水稻细菌性条斑病菌侵入途径研究

在温室和田间用8种接种方法对水稻的气孔、水孔及伤口接种水稻细菌性条斑病菌和白叶枯病菌,进行了3年的病菌侵入途径研究。结果表明,水稻白叶枯病菌通过气孔和各种伤口侵染植株。而水稻细条病菌通过气孔和微伤口引起发病,伤口和气孔同时被侵入,发病普遍而严重。通过对202个水稻品种的显微形态观测表明,气孔密度和开张度与品种发生细条病的轻重有一定关系,它们可作为品种形态抗性的一个参数。     

A single amino acid substitution in PthA of <Emphasis Type="Italic">Xanthomonas axonopodis</Emphasis> pv. <Emphasis Type="Italic">citri</Emphasis> altering canker formation on grapefruit leaves

The typical citrus canker lesions produced by Xanthomonas axonopodis pv. citri are erumpent, callus-like, with water-soaked margins. Three novel atypical symptom-producing variants of X. axonopodis pv. citri were described recently in Taiwan. Only the variant designated as A^f type produces typical erumpent canker lesions on Mexican lime (Citrus aurantifolia) but induces flat necrotic with water-soaked margin lesions on grapefruit leaves (C. paradisi). Two homologous pthA were cloned and characterized from strains XW19 (a typical canker lesion producing strain) and XW47 (a strain of A^f type). The pthA homolog from XW19 was transformed into XW47. The transformant of XW47 induced typical erumpent canker lesions on grapefruit leaves. Sequence analyses of transformants XW19 and XW47 revealed over 99% homology in nucleotide and deduced amino acid sequences compared with pthA homologs deposited in GenBank. The amino acid residues located at positions 49, 286, 742 and 767 of PthA were different between XW47 and XW19. The PthA mutants with a single amino acid substitution at each of these four positions were constructed by site-directed mutagenesis. Modified PthA (S286P) from XW47 in transformant 47SP induced erumpent canker lesions on grapefruit leaves, whereas another modified PthA (P286S) from XW19 in transformant 47PS only induced flat necrotic lesions. These results suggested that a single amino acid substitution from either serine to proline or proline to serine at position 286 of PthA can alter canker formation by X. axonopodis pv. citri on grapefruit leaves.     

几种生化物质与西瓜抗蚜性的相关性

为了初步探讨西瓜抗蚜性的营养与次生代谢物质防御效应,采用分光光度法测定并分析了几种生化物质与西瓜抗蚜性的相关性。结果表明,抗性品种黑皮、绿美人、黑美人和惠兰的游离氨基酸、脯氨酸和可溶性氮含量分别为2.22~2.27、0.23~0.26和1.88~3.03 mg/g,显著低于感性品种金美人、小玲、甜美人和花绿的3.24~3.83、0.67~0.87和5.26~5.82 mg/g;抗性品种的糖/氮比为5.38~7.94,显著高于感性品种;抗、感品种间可溶性糖和维生素C(Vc)含量无显著差异;瓜蚜为害4 d后的抗性品种叶组织中的总酚和单宁酸含量显著增加,感性品种显著降低;丙二醛含量增加幅度显著高于抗性品种。研究表明,西瓜品种抗蚜性与糖/氮比及总酚、单宁酸含量均呈显著正相关,与可溶性氮、游离氨基酸、脯氨酸及丙二醛含量均呈显著负相关,但与可溶性糖和Vc含量无显著相关性。     

八种十字花科寄主植物真叶和子叶的化学成分及其对小菜蛾生长发育及生理代谢的影响

为明确小菜蛾Plutella xylostella对寄主植物真叶和子叶的适合度,于室内测定8种十字花科植物改良青杂3号、改良露头青、陕油0913、甘杂1号、超级火箕青、四月慢、绿球66和中花尖叶芥蓝真叶和子叶的营养物质和次生代谢物质的含量,并测定取食后小菜蛾幼虫的取食选择性、发育历期、蛹重、保护酶和解毒酶活性。结果显示,8种寄主植物真叶的可溶性糖、总氨基酸、单宁、类黄酮和总酚含量之间差异显著,且大部分均显著高于其子叶,8种寄主植物子叶的可溶性糖、总氨基酸、单宁、类黄酮和总酚含量之间也差异显著。小菜蛾3龄幼虫偏好取食真叶;取食8种寄主植物真叶后成虫前期的发育历期为12.3～16.3 d,取食子叶后成虫前期的发育历期为14.3～18.6 d;取食子叶的蛹重明显低于取食其真叶;取食8种寄主植物真叶的小菜蛾幼虫体内超氧化物歧化酶（superoxide dismutase,SOD）、过氧化物酶（peroxidase,POD）、过氧化氢酶（catalase,CAT）、谷胱甘肽S-转移酶（glutathione S-transferase,GST）、羧酸酯酶（carboxylesterase,Car...     

Survey of mutations of a histidine kinase gene BcOS1 in dicarboximide-resistant field isolates of Botrytis cinerea

Previously, we cloned a putative osmosensing histidine kinase gene (BcOS1) and revealed that a single amino acid substitution, isoleucine to serine at codon 365, conferred dicarboximide resistance in field isolates of Botrytis cinerea. This point mutation (type I) occurred within the restriction enzyme TaqI site of the wild-type BcOS1 gene. Thus, a procedure was developed for detecting the type I mutation of the BcOS1 gene using a polymerase chain reaction (PCR) in combination with restriction fragment-length polymorphism (RFLP). Diagnosis by PCR-RFLP was conducted on the 105 isolates isolated from 26 fields in Japan. All dicarboximide-sensitive isolates (49 isolates) had the wild-type BcOS1 gene, and the 43 isolates with the type I mutation were resistant to dicarboximides without exception. These data indicate that dicarboximide-resistant isolates with type I mutation are widespread throughout Japan. However, other types of dicarboximide resistance were detected among isolates from Osaka; among the 24 resistant isolates from Osaka, 12 had the BcOS1 gene without the type I mutation. BcOS1 gene sequencing of these resistant isolates classified them into two groups, type II and type III. The type II isolates have three amino acid substitutions within BcOS1p (³⁶⁸Val to Phe, ³⁶⁹Gln to His, and ⁴⁴⁷Thr to Ser). The type III isolates have two amino acid substitutions within BcOS1p (³⁶⁹Gln to Pro and ³⁷³Asn to Ser). These amino acid changes are located on the amino acid repeat domain in BcOS1p. The three types of resistant isolates were all moderately resistant to dicarboximides without significant osmotic sensitivity, and their pathogenicity on cucumber leaves was also very similar to that of the wild-type isolate.     

Involvement of Iron and Ferritin in the Potato–Phytophthora infestans Interaction

This work shows that the infection of potato (Solanum tuberosum) detached leaves by the late blight pathogen Phytophthora infestans, was drastically reduced by adding deferoxamine, an exogenous iron chelator. Reactive oxygen species in leaves inoculated with P. infestans were also reduced after adding deferoxamine. A leaf ferritin cDNA fragment was obtained by PCR and used as probe for screening a tuber cDNA library. A cDNA (named StF1) encoding the iron-storing potato ferritin was cloned. StF1 is 915 bp in length and has an open reading frame of 230 amino acids that contains the information for the mature 28 kDa subunit of potato ferritin. StF1 was used as probe in northern blot hybridizations to analyze expression of the ferritin gene. In leaves, ferritin mRNA accumulated in response to pathogen attack. In tubers, ferritin mRNA increased upon treatment with the elicitor eicosapentaenoic acid. These results suggest that iron plays a role in the potato-P. infestans interaction.